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  • Inorganic Chemistry  (83,665)
  • 42.75
  • Limnology
  • Wiley-Blackwell  (83,665)
  • Exeter, UK  (31)
Collection
Years
  • 1
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11119 | 1256 | 2013-04-06 16:10:00 | 11119 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Axe Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Axe Salmon Action Plan (SAP). This strategy represents an entirely new approach to salmon management within the UK and introduces the concept of river-specific salmon spawning targets as a salmon management tool. This document is part of a national initiative to produce action plans for the management of all the main salmon rivers of England and Wales by 2003. The aim of this plan is (i) to assess the status of the salmon stocks and fisheries of the River Axe - including the use of Conservation Limits as part of this process, (ii) to identify factors which may be limiting stock and fishery performance and (iii) to propose remedial measures address these factors. The salmon stock of the River Axe was apparently in a healthy state in the 1950s, supporting net and rod fisheries with average annual catches of around 100 and 50 fish respectively. Catches declined through the 1970s and 1980s to the extent where no salmon were recorded in the late 1980s and early 1990s. This decline was probably due largely to the effects of agricultural pollution, which virtually extinguished the salmon stock of the River Axe. Water quality has subsequently improved, but has deteriorated again in recent years.
    Description: Environment Agency Archives North West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Axe ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fish catch statistics ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
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  • 2
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11125 | 1256 | 2013-04-06 15:59:47 | 11125 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Lyn Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Lyn Salmon Action Plan (SAP). This approach to salmon management within the England and Wales introduces the concept of river-specific Conservation Limits as a method of assessing the status of the salmon stock. The River Lyn Salmon Action Plan follows the format of those completed for the Rivers Exe, Axe, Avon & Erme, Teign, Torridge, Taw and Dart. It is the last of eight action plans that have been produced for salmon rivers within Devon Area. The River Lyn Salmon Action Plan contains a description of the river catchment and highlights particular features that are relevant to the salmon population and the associated fishery. The Lyn salmon stock is judged to be meeting its Conservation Limit. However, this assessment is uncertain as it is based on an estimate of rod exploitation rate, which in itself is also uncertain.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Lyn ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fish catch statistics ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 55
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  • 3
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11117 | 1256 | 2013-04-06 16:10:16 | 11117 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the Rivers Avon & Erme Salmon Action Plan Consultation document produced by the Environment Agency in 2003. This document is part of a national initiative to produce action plans for the management of all the main salmon rivers of England and Wales by 2003. The aim of this plan is (i) to assess the status of the salmon stocks and fisheries of the rivers Avon and Erme - including the use of Conservation Limits as part of this process, (ii) to identify factors which may limiting stock and fishery performance and (iii) to propose remedial measures address these factors. The report pays attention on the external consultation of the Rivers Avon & Erme Salmon Action Plan (SAP). While the stocks of both rivers have exceeded their respective conservation limits occasionally in individual years, only the Erme has achieved a period of statistical compliance since 1993. It is possible that this situation is largely normal, due to the steep nature of the rivers, obstructions to migration and dependence on suitable flow conditions occurring at the right time of year. The decline of the spring-running component of the stocks has left the populations dependent on autumn flows for the success of the late running component. Actions required to improve compliance with Conservation Limits are proposed and prioritised. The urgent actions relate to the need to improve the consistency with which adequate numbers of salmon reach and utilise fully all the accessible areas of the river systems. This document is intended to be dynamic, with opportunities for review occurring at regular intervals. For example, as the science of fisheries management improves, particularly in the setting of Conservation Limits, so the targets may be altered to reflect any improved methodology.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; Rivers Avon & Erme ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fish catch statistics ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 68
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  • 4
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11123 | 1256 | 2013-04-06 16:09:16 | 11123 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Exe Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Exe Salmon Action Plan (SAP). This strategy represents an entirely new approach to salmon management within the UK and introduces the concept of river-specific salmon spawning targets as a salmon management tool. The River Exe SAP follows the format of those completed for the Rivers Teign, Torridge, Taw and Dart. It is the fifth of eight action plans that will be produced for salmon rivers within Devon Area. The River Exe SAP contains a description of the river catchment and highlights particular features that are relevant to the salmon population and the associated fishery. The Exe salmon stock is judged to be meeting its Conservation Limit. However, this assessment is uncertain as it is based on an estimate of rod exploitation rate, which in itself is also uncertain. At present there is no means of accurately assessing the River Exe salmon run. In common with many other rivers, estimation of stock using catch statistics and rod exploitation rate is the model used, when direct assessment is not possible. The installation of a fish counter on the lower river, or the use of other direct counting methods, would help to provide a direct assessment of the annual run of salmon into the river. This would improve our ability to estimate the spawning escapement and hence assess compliance with the Conservation Limit.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Exe ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fish catch statistics ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 72
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  • 5
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11129 | 1256 | 2013-04-06 15:57:09 | 11129 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Teign Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Teign Salmon Action Plan (SAP). This approach to salmon management within the England and Wales introduces the concept of river-specific Conservation Limits as a method of assessing the status of the salmon stock. The River Teign Salmon Action Plan follows the format of those completed for the Rivers Torridge, Taw and Dart. It is the fourth of eight action plans that will be produced for salmon rivers within the Devon Area Fisheries, Recreation and Biodiversity Team. The River Teign SAP contains a description of the river catchment and highlights particular features that are relevant to the salmon population and the associated fishery. The Teign salmon stock is currently failing to meet its conservation limit. This failure is largely attributed to the reduction in the survival rate during the marine phase of the salmon life cycle. This is likely to constrain stocks to lower levels than have existed historically. Still further catch controls may contribute to a reduction in exploitation rates and allow stocks to recover to meet their conservation limit. Other important actions include the continuation of habitat improvement works which aim to maximise spawning habitat utilisation, spawning success, and juvenile survival and production.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Exeter ; River Teign ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fish catch statistics ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 53
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  • 6
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11131 | 1256 | 2013-04-06 15:56:47 | 11131 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Torridge Salmon Action Plan Final document produced by the Environment Agency in 2000. This final Salmon Action Plan (SAP) for the River Torridge catchment has been produced after consideration of feedback from external consultation. The SAP provides a list of the issues and actions which were agreed for a five-year programme to maintain and improve the River Torridge salmon stock. Some of these actions have already been delivered before finalising the SAP, but others have yet to be addressed. An attempt has been made to estimate the cost of the actions, identify possible sources of funding and the timescale under which they will be dealt with. The Torridge salmon stock has declined dramatically since the 1960s and is currently failing to meet the spawning target. The decline in the spring fish component has accounted largely for the overall decrease in stocks. The reasons for the decline are not fully understood, but the spring fish problem is recognised as a national issue. The rate of survival over the marine phase has reduced in recent years for both the grilse and multi-sea winter (MSW) components. This is undoubtedly a contributory factor, which may now constrain stocks to lower levels than have existed historically. Agricultural pollution is recognised as one of the main factors limiting freshwater production. This SAP aims to promote long term collaboration between the Agency and other interested parties in managing the River Torridge salmon stock and fisheries.
    Description: Environment Agency Archives North West
    Keywords: Fisheries ; Limnology ; Management ; England ; Exeter ; River Torridge ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
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  • 7
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    Devon River Board | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10866 | 1256 | 2013-03-26 13:40:44 | 10866 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the fourth River Dart Scale Reading Investigation Report on the 1965 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All it summarized in tables, and figures are included plotting weight distributions for each age classes and frequency distributions.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Freshwater fish ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
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    Format: 10
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  • 8
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10868 | 1256 | 2013-03-26 13:40:27 | 10868 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the sixth and final River Dart Scale Reading Investigation Report on the 1967 Season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All it summarized in tables, and figures are included plotting weight distributions for each age classes and frequency distributions. It also compares the results of previous reports and gives a full summary for the investigation (including previous reports).
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Freshwater fish ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
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    Format: 17
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  • 9
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    Devon River Board | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10867 | 1256 | 2013-03-26 13:40:36 | 10867 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the fifth River Dart Scale Reading Investigation Report on the 1966 Season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All it summarized in tables, and figures are included plotting weight distributions for each age classes and frequency distributions. It also compares the results of previous reports.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Freshwater fish ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
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  • 10
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    Devon River Board | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10869 | 1256 | 2013-03-26 13:42:19 | 10869 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the first River Dart Scale Reading Investigation Report on the 1962 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews briefly the theory and mechanics of the scale-reading technique, the life history of the salmon, and the methods used for the collection of scales and the examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in various tables and figures are also included, plotting weight distributions for each age classes and frequency distributions.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Freshwater fish ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
    Type: monograph
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  • 11
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10881 | 1256 | 2013-04-01 17:23:27 | 10881 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the River Dart Scale Reading Investigation Report on the 1972 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. In 1967 the final report on a five-year scale reading programme was summarised, at the time it was considered sufficient information to help with restocking programmes and the management of salmon population. But a further scale reading programme was started in an attempt to monitor changing patterns in salmon runs that may be caused by the new influences. It reviews the methods used for collection of the scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
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  • 12
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10892 | 1256 | 2013-03-26 13:28:07 | 10892 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the 5th Annual Report of the Rive Exe Scale Reading Investigation for the 1970 season by the Devon River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon population of the River Exe. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Exe ; River fisheries ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species ; Population density
    Repository Name: AquaDocs
    Type: monograph
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  • 13
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10893 | 1256 | 2013-10-27 13:08:58 | 10893 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the 6th Annual Report of the Rive Exe Scale Reading Investigation for the 1971 Season by the Devon River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon population of the River Exe. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Exe ; River fisheries ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species ; Population density
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
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  • 14
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11120 | 1256 | 2013-04-06 16:09:51 | 11120 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Axe Salmon Action Plan Final document produced by the Environment Agency in 2004. The River Axe Salmon Action Plan (SAP) has been produced after consideration of feedback from public consultation. The final plan provides a list of the agreed issues and actions for the next five years to maintain and improve the salmon stock of the River Axe. Efforts have been made to identify possible sources of funding, partners and timescales. It indicates how the plan will be managed, including the process for reviewing stock status, issues, actions and progress. Low marine survival is currently a major factor limiting salmon stocks throughout the United Kingdom. However, on the River Axe the freshwater environment is still the main factor limiting the recovery of the salmon stock. Most of the adults returning to the Axe at present are probably derived from hatchery reared smolts, although there has been some natural reproduction in recent years. Juvenile populations in the Yarty indicate that this is a tributary where salmon have started to re-establish a self-sustaining population. Actions to improve the quality of the freshwater environment, both in terms of water quality and sedimentation, are seen as the top priorities, and are required to allow the Axe to support a self-sustaining salmon population.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; Rivers Axe ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
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  • 15
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11121 | 1256 | 2013-04-06 16:09:43 | 11121 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Dart Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Dart Salmon Action Plan (SAP). This strategy represents an entirely new approach to salmon management within the UK and introduces the concept of river-specific salmon spawning targets as a salmon management tool. The north of the River Dart catchment is included in the Dartmoor candidate Special Area of Conservation (cSAC), designated under the Council EC Directive 92/43/EEC, the “Habitats Directive”. One of the conservation objectives for the cSAC is to maintain the habitat for Atlantic Salmon, Salmo Salar in favourable condition. The River Dart is an important salmon, sea trout and brown trout fishery with no significant coarse fishery. However, eels are ubiquitous throughout the catchment and are lightly exploited. The River Dart SAP contains a description of the river catchment and highlights particular features that are relevant to the salmon population and the associated fishery.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; Rivers Dart ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fish catch statistics ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
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  • 16
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11126 | 1256 | 2013-04-06 15:59:23 | 11126 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Lyn Salmon Action Plan Final document produced by the Environment Agency in 2003. This final Salmon Action Plan (SAP) for the River Lyn catchment has been produced after consideration of feedback from external consultation. It provides a list of the agreed issues and actions for the next five years to maintain and improve the River Lyn salmon stock. The actions presented within this Salmon Action Plan clarify the important issues and factors currently limiting the salmon stock on the river. The resolution of these issues should ensure that a sustainable salmon population will be maintained for future generations. An attempt has been made to cost these actions, identify possible sources of funding and to provide a timescale for action. This SAP aims also to promote long term collaboration between the Agency and other interested parties in managing the River Lyn salmon stock and fisheries.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Lyn ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
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  • 17
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10894 | 1256 | 2013-03-26 13:27:46 | 10894 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the 7th Annual Report of the Rive Exe Scale Reading Investigation for the 1972 Season by the Devon River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon population of the River Exe. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Exe ; River fisheries ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species ; Population density
    Repository Name: AquaDocs
    Type: monograph
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  • 18
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11124 | 1256 | 2013-04-06 16:08:24 | 11124 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Exe Salmon Action Plan Final document produced by the Environment Agency in 2003. This final Salmon Action Plan (SAP) for the River Exe catchment has been produced after consideration of feedback from external consultation. The actions presented within this Salmon Action Plan clarify the important issues and factors currently limiting the salmon stock on the river. An attempt has been made to cost these actions, identify possible sources of funding and to provide a timescale for action. This SAP aims also to promote long term collaboration between the Agency and other interested parties in managing the River Exe salmon stock and fisheries. The River Exe salmon population is currently judged to be passing its Conservation Limit. However, its apparent declining trend in egg deposition in the recent years and the high uncertainty in its stock assessment suggest the following actions as priorities: actions promoting good land management, maximising salmon natural spawning activity and protecting smolts throughout the Exe catchment. Also, the lack of information on salmon stocks and its habitat quality and availability is recognised as the main factor limiting the better management of salmon fisheries. The actions presented in this document are perceived as those required to address the important issues and factors limiting the salmon stock.
    Description: Environment Agency Archives North West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Exe ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
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  • 19
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11128 | 1256 | 2013-04-06 15:57:17 | 11128 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Taw Salmon Action Plan Final document produced by the Environment Agency in 2000. This final Salmon Action Plan (SAP) for the River Taw catchment has been produced after consideration of feedback from external consultation. The SAP provides a list of the issues and actions which were agreed for a five-year programme to maintain and improve the River Taw salmon stock. Some of these actions have already been delivered before finalising the SAP, but others have yet to be addressed. An attempt has been made to estimate the cost of the actions, identify possible sources of funding and the timescale under which they will be dealt with. The Taw salmon stock is currently failing to meet its spawning target. However, there was a period of compliance in the 1990s following a decade of failure through the 1980s. The freshwater environment of the Taw has improved in recent years. The actions presented in this SAP are perceived as those that are required to address, as far as possible, the important issues and factors currently limiting the salmon stock on the river. This SAP aims to promote long term collaboration between the Agency and other interested parties in managing the River Taw salmon stock and fisheries.
    Description: Environment Agency Archives North West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Taw ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11122 | 1256 | 2013-04-06 16:09:36 | 11122 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Dart Salmon Action Plan Final document produced by the Environment Agency in 2003. This final Salmon Action Plan (SAP) for the River Dart catchment has been produced after consideration of feedback from external consultation. It provides a list of the agreed issues and actions for the next five years to maintain and improve the River Dart salmon stock. The low marine survival (likely to be below 10%) is possibly to be the main cause for the River Dart salmon stock non-compliance with its conservation limit. Actions protecting smolts and maximising spawning activity of returning adults are seen as priorities to contribute to mitigate the low marine survival. Also the lack of information on salmon stock and its habitat is recognised as one main factor limiting the better management of salmon fisheries. Efforts will be focused on gaining more knowledge and improving modelling techniques. The actions presented in this document are perceived as those required to address the important issues and factors limiting the salmon stock. This SAP aims also to promote long term collaboration between the Agency and other interested parties in managing the River Dart salmon stock and fisheries.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Dart ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11118 | 1256 | 2013-04-06 16:10:08 | 11118 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the Rivers Avon & Erme Salmon Action Plan Final document produced by the Environment Agency in 2004. The Rivers Avon and Erme Salmon Action Plan (SAP) has been produced after consideration of feedback from public consultation. The final plan provides a list of the agreed issues and actions for the next five years to maintain and improve the salmon stocks and fisheries of both rivers. Efforts have been made to identify possible sources of funding, partners and timescales. It indicates how the plan will be managed, including the process for reviewing stock status, issues, actions and progress. Low marine survival is currently a major factor limiting the numbers of salmon returning to spawn in both the Avon and the Erme. Actions to improve the accessibility of spawning areas and to maximise the productivity of spawning and nursery habitats are seen as priorities, which should help to offset the low marine survival. The quality of the information available to assess salmon stocks is recognised as a limiting factor in the management of salmon fisheries. The SAP aims also to promote long term collaboration between the Agency and other interested parties in managing the salmon stocks and fisheries of the Avon and the Erme.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; Rivers Avon & Erme ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
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  • 22
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11127 | 1256 | 2013-04-06 15:57:29 | 11127 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Taw Salmon Action Plan Consultation document produced by the Environment Agency in 2000. The report pays attention on the external consultation of the River Taw Salmon Action Plan (SAP). This approach to salmon management within the England and Wales introduces the concept of river-specific Conservation Limits as a method of assessing the status of the salmon stock. The River Taw Salmon Action Plan (SAP) includes a description of the current status of the rod and net fisheries and historical trends. The Taw salmon stock has declined since the 1960s and is currently failing to meet the spawning target. The decline in the spring fish component has accounted largely for the overall decrease in stocks. The reasons for the decline are unclear, but the spring fish problem is recognised as a national issue. The rate of survival over the marine phase has reduced in recent years for both the grilse and MSW components. This is undoubtedly a contributory factor, which may now constrain stocks to lower levels than have existed historically.
    Description: Environment Agency Archives North West
    Keywords: Fisheries ; Limnology ; Management ; England ; Cornwall ; River Taw ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fish catch statistics ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
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    Environment Agency | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/11130 | 1256 | 2013-04-06 15:58:59 | 11130 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-06-28
    Description: This is the River Teign Salmon Action Plan Final document produced by the Environment Agency in 2003. This final Salmon Action Plan (SAP) for the River Teign catchment has been produced after consideration of feedback from external consultation. This final plan provides a list of the agreed issues and actions for the next five years to maintain and improve the River Teign salmon stock. An attempt has been made to cost these actions, identify possible sources of funding, partners and the timescale under which they will be dealt with. It indicates how the plan will be managed, i.e., implemented and reviewed, and, summarises progress of on-going actions. The low marine survival (likely to be below 10%) is possibly the main cause for the River Teign salmon stock non-compliance with its conservation limit. Actions protecting smolts and maximising spawning activity of returning adults are seen as priorities to contribute to offset the low marine survival. This SAP aims also to promote long term collaboration between the Agency and other interested parties in managing the River Teign salmon stock and fisheries.
    Description: Environment Agency Archives North West
    Keywords: Fisheries ; Limnology ; Management ; England ; Exeter ; River Teign ; Inland waters ; Freshwater fish ; Migratory species ; Salmon Action Plan ; Fishery data ; Fishery management ; Fishery regulations ; Nature conservation ; Water quality ; Spawning targets
    Repository Name: AquaDocs
    Type: monograph
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  • 24
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    Devon River Board | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10870 | 1256 | 2013-03-26 13:41:33 | 10870 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the second River Dart Scale Reading Investigation Report on the 1963 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in tables, and figures are alo included plotting weight distributions for each age classes and frequency distributions. The report also remarks the similarity of the results with those for 1962.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Freshwater fish ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
    Type: monograph
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  • 25
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    Devon River Board | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10871 | 1256 | 2013-03-26 13:40:55 | 10871 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the third River Dart Scale Reading Investigation Report on the 1964 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in tables, and figures are also included plotting weight distributions for each age classes and frequency distributions. After three years of the investigation a pattern is emerging which shows that the Dart salmon population is mainly composed of four year old fish, which have spent two years in the river and then two year or little longer at sea.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Freshwater fish ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
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  • 26
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10890 | 1256 | 2013-03-26 13:35:47 | 10890 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the River Erme Fisheries Survey, 1965 by the Devon River Authority.The survey was carried out during April and May 1965, with the principal object being the determination of the abundance and distribution of salmonid fish in the River Erme in relation to the discharge from Stowford Paper Mills, Ivybridge. It contains a brief introduction of general aspects of the catchment, chemistry, pollution, biology and fisheries in the river, methodology that looks at the selected transects and techniques for sampling, results and recommendations. It contains tables with totals of all salmonid fish found at each section, size distribution of trout, surface area of section and population density.
    Description: Environment Agency Archives North West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Erme ; River fisheries ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species ; Population density
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  • 27
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10872 | 1256 | 2013-03-26 13:52:39 | 10872 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the first River Dart Fisheries Survey produced by the Devon River Authority; which was carried out from May to October 1965. The objective was to examine the distribution and relative abundance of salmonid fish in the River Dart, in order to assess the possibility or desirability, of increasing salmon smolt production of the river by artificial propagation or other means.Description, chemical, pollution and biological conditions of the River Dart along with fisheries catches, water extraction and spawning are briefly cited. The method includes the choice of sections and sampling techniques. The results go through the number/type/class of fishes counted while the survey took place, distribution patterns within the different transects/brooks, competition between salmon parr and trout and estimations of population. The section on the discussion and recommendations is introduced by a brief explanation of the bases for the Artificial Propagation Programme and the River Dart specific case-study. The annexes contains River Dart and tributaries maps, fish size distribution tables and figures, tables with totals of salmonid fish found and population density tables.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; Rivers ; River fisheries ; Freshwater fish ; Salmon fisheries ; Salmo salar ; Salmo trutta ; Fishery surveys ; Fish populations ; Population structure ; Stock assessment
    Repository Name: AquaDocs
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  • 28
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10873 | 1256 | 2013-03-26 13:52:09 | 10873 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the second River Dart Fisheries Survey produced by the Devon River Authority; which was carried out from April to July, 1969. The objective was to examine the distribution and relative abundance of salmonid fish in the River Dart, in order to assess the possibility or desirability, of increasing salmon smolt production of the river by artificial propagation or other means.In addition to the tributaries examined in the 1965 survey, further sections were studied on the River Hems and Holy Brook and reference should be made to the River Survey Report, 1965 for introductory information. The method includes the choice of sections and sampling techniques. The results go through the number/type/class of fishes counted while the survey took place and distribution patterns within the different transects/brooks. The discussion tries to remark the importance of understanding the differences between 1965 and 1969 surveys. The Appendix contains tables with totals of salmonid fish found and distribution sizes for each section, population density tables and a map with new surveyed sections.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; Rivers ; River fisheries ; Freshwater fish ; Migratory species ; Salmon fisheries ; Salmo salar ; Salmo trutta ; Fishery surveys ; Fish populations ; Population structure ; Stock assessment
    Repository Name: AquaDocs
    Type: monograph
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  • 29
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    South West Water Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10874 | 1256 | 2013-03-26 13:51:40 | 10874 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the River Dart Fisheries Survey 1974 report produced by the South West Water Authority. The survey was carried out between July and October 1974 to assess the extent of the 0+ and 1+ Salmo salar L. population in the Dart catchment and thereby assess directly the success of the 1973/74 and 1972/73 spawning season. The survey showed that there were large numbers of salmon parr distributed throughout the upper reaches of the Dart, reflecting the successful spawning of the 1973/74 and 1972/73 season. It contains tables with survey sections locations, presence/absence for each section and location maps with spawning grounds and sampling stations.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; Rivers ; River fisheries ; Freshwater fish ; Migratory species ; Salmon fisheries ; Salmo salar ; Salmo trutta ; Fishery surveys ; Stock assessment ; Spawning ; Population structure ; Stocking
    Repository Name: AquaDocs
    Type: monograph
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  • 30
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    University of Exeter, Hatherley Biological Laboratories | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10884 | 1256 | 2013-03-26 13:39:45 | 10884 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the Report to the Devon River Board on the investigations in the Walla Brook (1955-58). This report provides information on the nature and quantification of the bottom fauna, the population of fish and their habits and behaviour throughout the year, and the relation of this fish population to the potential stock-carrying capacity of the river. It includes a bottom fauna list with occurring invertebrates and an Addendum to the report.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; Rivers ; River fisheries ; Salmon fisheries ; Environmental monitoring ; Population dynamics ; Migratory species ; Water quality
    Repository Name: AquaDocs
    Type: monograph
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  • 31
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    Devon River Authority | Exeter, UK
    In:  dis@fba.org.uk | http://aquaticcommons.org/id/eprint/10880 | 1256 | 2013-03-26 13:40:06 | 10880 | Environment Agency, UK (Freshwater Biological Association)
    Publication Date: 2021-07-01
    Description: This is the River Dart Scale Reading Investigation Report on the 1971 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. In 1967 the final report on a five-year scale reading programme was summarised, at the time it was considered sufficient information to help with restocking programmes and the management of salmon population. But a further scale reading programme was started in an attempt to monitor changing patterns in salmon runs that may be caused by the new influences. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All are summarized in tables, and figures are also included plotting weight distributions for each age classes and frequency distributions.
    Description: Environment Agency Archives South West
    Keywords: Fisheries ; Limnology ; Management ; England ; South West ; River Dart ; River fisheries ; Salmon fisheries ; Fish populations ; Population structure ; Population dynamics ; Migratory species
    Repository Name: AquaDocs
    Type: monograph
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  • 32
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 55-62 
    ISSN: 0009-2940
    Keywords: Diastereoselective hydrogenation ; Folic acid ; Immobilized optically active rhodium(I)/diphosphane catalysts ; Leucovorin ; HPLC analysis of 5-formyltetrahydrofolic acid derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the hydrogenation of the C=N bonds in the pyrazine ring of the vitamin folic acid (1) optically active rhodium(I)/diphosphane complexes immobilized on supports such as silica gel or Al2O3 were used. The reduction was carried out at 50 bar hydrogen pressure in an aqueous solution buffered to pH 7. Thus, 5,6,7,8-tetrahydrofolic acid (2) was obtained which contains a new asymmetric center at C-6 of the pterine system. Therefore, in combination with the (S) configuration of the natural L-glutamic acid part of the molecule two diastereomers with (6S,S) and (6R,S) configuration arise. The relatively unstable tetrahydrofolic acid (2) was converted into its 5-formyl derivative folinic acid (4) by treatment with methyl formate/formic acid in a 5:1 mixture of DMSO/pyridine. The Ca salt of folinic acid (4) is the widely used drug leucovorin. The diastereomers were separated by silica gel HPLC. To the column bovine serum albumine (BSA) is covalently bound. With optically active rhodium(I)/diphosphane catalysts, immobilized on silica gel supports, a diastereoselectivity of up to 90% could be achieved in the hydrogenation of folic acid (1).
    Additional Material: 1 Ill.
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  • 33
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 83-88 
    ISSN: 0009-2940
    Keywords: Torsional (Z/E) isomerization ; Selectivity, regio- and stereo- ; Allylsilanes ; Allylic oxidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alk-2-enylpotassium compounds having the endo conformation are synthetically very valuable precursors of (Z)-olefinic derivatives substituted at the outward allylic position. They may be generated by „stereoconservative‘ metalation of the readily available (Z)-alk-2-enes by using the superbasic mixture of butyllithium and potassium tert-butoxide or by metalation under similar conditions of stereorandom mixtures of alk-2-enes or alk-1-enes followed by torsional isomerization of the concomitantly formed exo conformers to the thermodynamically more stable endo species. The principal factors that dictate the rate and the extent of the endo/exo equilibration are the substrate geometry, the solvent, the temperature, the reagent stoichiometry, and catalysis.
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  • 34
    ISSN: 0009-2940
    Keywords: Phosphaalkynes ; Triorganoaluminium compounds ; Cooligomerization ; Cage compounds ; Aluminium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When the trialkylaluminium reagents 5 are allowed to react with phosphaalkynes 4 in n-pentane, a highly selective phosphaalkyne cyclotrimerization with incorporation of two organometallic units occurs (→ 6). The tetracyclooctane derivatives 6a-e represent the first examples of phosphorus-aluminium-carbon cage compounds. The polycyclic products 6 are able to function as ligands in transition-metal complexes (→ 7), which is illustrated by the reactions of 6b, c with nonacarbonyldiiron and pentacarbonyl(tetrahydrofuran)tungsten, respectively.
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  • 35
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 283-289 
    ISSN: 0009-2940
    Keywords: Zinc ; Sulfonate ligands ; Perchlorates ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts are reported to incorporate sulfonate and perchlorate anions as ligands in zinc complexes of tripodal ligands. Using tris(benzimidazolylmethyl)amine (BIMA) only the aqua complexes [ (BIMA)Zn-OH2](RSO3)(ClO4) and [(BIMA)Zn-OH2](RSO3)2(R=CH3, CF3, p-tolyl) were accessible. Using substituted pyrazolylborates (Tp*), the same three sulfonate anions were found to be ligands in the complexes Tp*Zn-OSO2R. Spectroscopic evidence for perchlorate coordination in Tp*ZnClO4 · 2 DMSO conflicts with crystallograpic evidence against it in Tp*ZnClO4 · pyridine. The crystal structures of [(BIMA)Zn-OH2](CH3SO3)2, TpCum,MeZn-OS02CH3, TPtBu,MeZn-OSO2C6H4-p-CH3, and [TpCum,MeZn · NC5H5]ClO4 were determined.
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    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 295-298 
    ISSN: 0009-2940
    Keywords: Rhenium ; Oxides ; Alkyl ligands ; Dirhenium compounds ; Metal-metal interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Most alkylrhenium(VII) oxides, e.g. ((cyclo)-C3H5)Re03 (2) are rather sensitive to temperature and moisture with the prominent exception of methyltrioxorhenium (1). The corresponding alkylrhenium(VI) oxides of formula [RR′(O)- Re(μ-O)]2 [R=R′=(cyclo)-C3H5 (3), iPr (4); R=CH3, R′=C2H5 (5), R=CH3, R′=iPr (6)] are much more stable in this regard. They can be handled in air at room temperature. They were synthesized from Re207 and dialkylzinc precursors, fully characterized and are available in much higher yields than their ReVII congeners. Mixed tetraalkyltetraoxodirhenium(VI) complexes (R # R′) synthesized from 1 and dialkylzinc compounds form as a mixture of cis/trans isomers. They are oily liquids at room temperature. The Re=O and Re-Re stretching force constants as a measure of the bond strengths, were determined from IR and Raman data.
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  • 37
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 479-488 
    ISSN: 0009-2940
    Keywords: Heterobimetallic complexes ; Carbene complexes ; Alkynes ; Coupling reaction ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sequential reaction of the dimethylamino(trimethylsilylethylnyl)carbene complexes [(CO)5M'=C(NMe2)C≡CSiMe3] [M' = W (1a)] with KF/THFMeOH, nBuLi and transition metal halides, [XMLn], affords heterobimetallic propynyliden complexes of the type [(CO)5M'=C(N-Me2)C≡CMLn] [MLn = Ni(PPh3) Cp (4a, b). Ni(PMe2Ph)2- {Mes) (Mes=2,4,6-C6H2Me3) (5a), Rh(CO)(PPh3)2 (6a), Fe(CO)2Cp (7a,b)]. In contrast, reaction of 1a with MeLi · LiBr and [IFe(CO)2Cp] yields the novel N-metallated complex [(CO)5W=C{N(ME)Fe(CO)2Cp}C≡CSiMe3] (8a). The complexes [(CO)5M'=C(NMe2)C≡CMLn=Fe(CO)2Cp (7a, b), Ru(CO)2Cp (10a,b), Ru(CO)(PPh3)Cp (11a), Mn(CO)5 (12a), Re(CO)5 (13a)] are accessible by Pd-catalyzed coupling of the C-stannylated carbene complexes [(CO)5M'=C-(NMe2)C≡CSnBu3] (9a, b) with [XMLn]. The related monomethylaminocarbene complexes [(CO)5M'=C(NHMe)C≡ CSnBu3] (16a, b), obtained by stannylation of [(C))5M'=C(NHMe)C=CH] (15a, B) with Bu3SnNEt2, react with [IFe(CO)2Cp] to give the bimetallic complexes [(CO)5M'=C(NHMe)C≡CFe(CO)2Cp] (17a, b). The complexes 4a, 5a, 7a and 10a were characterized by X-ray structural analysis. The spectroscopic and structural data suggest that the two metal centers in 4-7, 10-13, and 17 interact only weakly.
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    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 515-520 
    ISSN: 0009-2940
    Keywords: Water-soluble ligands ; Diazo compounds ; Photolysis ; Cleavage reactions ; Zinc ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The single-crystal X-ray structure analysis of the diazosulfonate p-H2N-C6H4-N=N-SO3Na 3 features a Z configuration of the diazo moiety and a nitrogen-sulfur bond. Each sodium atom is coordinated by one diazosulfonate substitutent in a chelating manner. Upon reaction of 3 with excess salicylaldehyde, the highly water-soluble Schiff base ligand 6 is obtained in good yield. Treatment of ZnCl2 with 2 equiv. of 6 gives the zinc complex 7. In all cases, the solubilizing diazosulfonate groups can be cleaved off photolytically, which offers an opportunity to precipitate the molecules from their aqueous solutions.
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  • 39
    ISSN: 0009-2940
    Keywords: Mercury ; Lanthanides ; Lanthanoid(II) complexes ; (N-2,6-Diisopropylphenyl)(N-trimethylsily)amide complexes ; Bis(trimethylsilyl)amide complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Mercury(II) amide complex Hg[N(SiMe3)(2,6-iPr2C6H3)]2 (1) was prepared by reaction of HgBr2 with Li[N(SiMe3) 2,6-iPr2C6H3)] in diethyl ether solvent. Redox transmetallation reactions of 1 with elemental samarium, europium or ytterbium in THF solvent (THF = tetrahydrofuran), generated the novel divalent complexes Ln[N(SiMe3)(2,6-iPr2C6H3]2(THF)2 with Ln = Sm (2), Eu (3) and Yb (4). 4 was also synthesized by reaction of elemental ytterbium, HgPh2 and HN(SiMe3)(2,6-Me3)2]2(THF)2 [Ln = Sm (5), Yb (6)] by reaction of the metals with HgPh2 and HN(SiMe3)2. Thermal desolvation of 4 under high vacuum gave Yb(N)(SiMe3)2,6-iPr2C6H3)]2 (THF) (7), whereas under identical conditions 6 yielded the solvent-free complex [Yb[N{SiMe3)2]2]2. (8). The new compounds 1-4 and 7 are hydrocarbon soluble and 171Yb-NMR spectra were recorded for 4, 6, 7 and 8. X-ray crystal structure determinations of 2 and 4 revealed four-coordinate, distorted tetrahedral metal environments augmented by weak Ln…ipso-C(aryl) interactions.
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  • 40
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 443-452 
    ISSN: 0009-2940
    Keywords: Ab initio calculations ; Azides ; Density functional calculations ; Covalent azides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The experimental and theoretical chemistry of covalently bound azides is an area that has seen considerable renaissance over the past 10 years. This review is not exhaustive in scope but rather focuses on and highlights certain aspects in this field. In particular, the stability and dissociation of HN3 is discussed at a very high level of theory (CASSCF and MCSCF-CI) and compared and contrasted with experimental data and results from „medium“-level ab initio computations (MP2, B-LYP). From these results credence is given to those values calculated for larger systems and heavy elements for which very high level computations are not possible. The experimentally well-characterized covalent halogen azides (XN3, where X = F, Cl, Br, I) as well as the heavy-element group-15 compound Sb(N3)3 are discussed. The review also includes discussion of the bond properties of the highly unstable N-bound azides ON-N3 and (FSO2)2N-N3. In the final chapter attention is drawn to the recently predicted and eventually experimentally verified elusive species OCN-NCO, which is isoelectronic to the hitherto unknown diazide N6.
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  • 41
    ISSN: 0009-2940
    Keywords: Tin ; Lead ; 119Sn NMR ; Salt metathesis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of Na2[M2(CO) 10] (M = Cr, Mo, W) with SnHal2 (Hal = Cl, Br) is a well established procedure for the synthesis of anions of type A, [{(CO)5M)SnHal3]-. Conditions are described which, for the same type of procedure, result in the additional formation of dianions of type B, [{(CO)5M}2SnHal2]2-. Procedures for separating these two types of anions in the form of their stable [Ph4P]+ or [nBu4N]+ salts by appropriate salt metathesis are presented. The structures of theses species have been characterized by X-ray analysis of three salts containing type A anions and two salts containing type B anions. The reactivity of the type B salts containing the bulky cations [Ph4P]+ or [nBu4N]+, respectively, is remarkably low; the salts are, however, transformed into highly reactive sodium salts by further metathesis with Na[BPh4]. In such salts the halide substitutents are easily exchanged as shown by the synthesis of ]})CO(5Cr}2oxinato]- (4)- from [Na-(THF)x]2[{(CO)5Cr}2SnCl2] and sodium 8-oxoquinolate, Na[C9H6NO]. The structure of the anion, 4 is compared to the structure of [[(CO)5Cr)SnCl2· THF] and sodium 8-oxochinolate. The preparation of the dinuclear anions [{(CO)5Cr}2E(OOCCH3)2]2- (E = Sn, 2g; E = Pb, 3) is accomplished by the reaction of [Ph4P]2[Cr2(CO)10] with the corresponding acetates E(OOCCH3)2. While 2g and 3 are formal analogues of the type-B anions, their structures reveal an asymmetrical η2-coordination of the two acetato ligands, in each case ending up in a 4+2 coordination for the main group centres, instead of the four-coordination observed for [{(CO)5M}2SnHal2]2-, All compounds have been characterized by usual spetroscopic and analytical techniques. X-ray analyses have been performed for selected examples. 119Sn-NMR data are presented for all of the compounds which contain tin-centred ligands.
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  • 42
    ISSN: 0009-2940
    Keywords: Phosphorus heterocycles ; 1H-Phosphirenes ; Nucleophilic substitution reactions at 1H-phosphirenes ; Metal-complexation of functionalized 1H-phosphirenes ; Carbonyl complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The halogen atoms in the 1-chloro-1H-phosphirenes, 5a-c, are easily substituted on reaction with organolithium and Grignard reagents, 14a-p, with formation of the corresponding O-, N-, C-, Si-, and Ge-substituted 1H-phosphirenes, 15a-t. C1/H exchange reactions also occur on reaction with lithium metal hydrides (5a → 17). Furthermore, substitution reactions are also realized with the alkali metal borates, 18a-g (→19a-g); the same is true for reactions with trimethylsilyl cyanide and azide (→22a-d). Some of the substitution products have been characterized in the form of their metal complexes, 16, 23, 24, and 25.
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  • 43
    ISSN: 0009-2940
    Keywords: Germatranes ; Organotrihalogenogermanes ; Organometallic (Si, Ge, Sn) reagents ; Transmetallation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trialkylstannyl esters of tris(2-hydroxyalkyl)amines, N(CH2CHROSnAlk3)3 (9-11 (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(R2)COOR3 (12-17) (X = Cl or Br; R1, R2=H, Me, Ph, SiMe3, COOEt; R3=Me, Et) to give esters of α-germatranylcarboxylic acids, N(CH2CHRO)3GeC(R1)(R2)-COOR3 (1-8), in high yields. The synthesis of esters 12-17 is reported. Esters of α-germatranyldiphenylacetic acid 24 and 25 can be obtained by treatment of diphenylketene with Et3SnOMe to give in situ Et3SnC(Ph2)COOMe (23), followed by reaction with GeCl4 to give in situ Cl3GeC(Ph2)COOMe (22 and further reactions with 9 or 11, respectively. Reduction of germatrane 6 with LiAlH4 in diethyl ether leads to cleavage of the germanium-carbon bond with subsequent formation of (2-hydroxyethyl)trimethylsilane. The crystal structures of 3, 6 and 7 are reported. 1-Acyloxygermatranes 26 and 27 are obtained by treatment of 1-methoxygermatrane (28) with diphenyl- and dichloroacetic acid, respectively.
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  • 44
    ISSN: 0009-2940
    Keywords: Tin - Nitrogen cage compounds ; Sn—X—Sn intramolecular bridges ; Distannylamine pyridine adduct ; Tin ; Moessbauer spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(dimethylchlorostannyl)amine (2a) reacts with pyridine in a 3:4 molar ratio to produce the tin-nitrogen containing bicyclo[3.1.1]heptane (3) with elimination of the adduct Me2SnCl2·2 py. Treatment of the distannylamine 2,6-[Pr2H3N(SnMe2Cl)2 (4) with pyridine, however, leads to the formation of the 1:1 pyridine adduct 4 and this can be regarded as a model to explain the route to 3. The molecular structures of 3 and 5 were determined by multinuclear magnetic resonance spectroscopy in solution, as well as by X-ray structure analysis of their crystals. Typical structural features for both compounds are intramolecular Sn—X—Sn bridges. Support for the structures comes from MS fragmentation patterns, IR spectra, and the Mössbauer spectra.
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  • 45
    ISSN: 0009-2940
    Keywords: 1,2,4-Diazaphospholes ; Phosphiranes, alkylidene- ; 2-Phosphabutadienes ; Phosphorus heterocycles ; pyrazolines, thermolysis ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 5-alkylidene-4,5-dihydro-3H-1,2,4(λ3)-diazaphospholes (4-phosphapyrazolines) are thermally much more stable than related compounds without the exocyclic double bond. Thermolysis reactions typically occur in the range 110-150°C in toluene solution, and different, mostly competing, reaction pathways are observed. Thermal extrusion of nitrogen from 8a-g gives rise to β-phosphanaylsiloxyalkenes 10, benzo[c]-phosphole derivatives 11, 14 and 115, (β-siloxyalkylidene)-Phosphiranes 12, and dihydro-1,3-oxaphospholes 13. The thermolysis of 5-alkylidene-4,5-dihydro-4-trimethylsilyl-3-trimethylsilyloxy-3H-1,2,4-dizaphospholes 17 afforded three products, including the highly substituted and stable 2-phosphabutadienes 18 formed by nitrogen extrusion and rearrangement. Finally, the 4-chloro-3-trimethylsilyloxy-substituted heterocycle 21 was transformed at 170°C into 4H-1,2,4-diazaphosphole 23. The structures of 13c and 18a were determined by single-crystal X-ray diffraction.
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  • 46
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 795-799 
    ISSN: 0009-2940
    Keywords: Boron ; Alkylations ; N ligands ; Dodecaborate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of the ammine-undecahydro-closo-dodecaborate(1-) anion with alkyl halides have been studied in detail. The degree of alkylation of the nitrogen was found to be dependent upon the steric demands of the alkyl groups. The derivatives were characterized by NMR and infrared spectroscopy. Four compounds were crystallized for single crystal X-ray diffraction studies. The tetrahedral coordination of the nitrogen atom of the bis-alkylated derivatives was found to deviate towards planarity with increasing steric hindrance of the substitutents. - The syntheses, crystal structures, and spectral properties of four N-alkyl derivatives of [H3N—B12H11]-, ammine - undecahydro-closo-dodecaborate(1-) (3), are reported. Alkylation of 3 with ethyl iodide was achieved in dimethyl sulfoxide using potassium hydroxide as base. This led to orthorhombic crystals of [N(nC4H94][(CH3CH2)3N—B12H11] (4). The reaction of 3 with benzyl chloride resulted in the bisbenzylated product, isolated as triclinic crystals of [PPN][(C6H5CH2)2 NH—B12H11] (5). The alkylation of 3 with 2-bromopropane gave a mixture of the mono- and bisalkylated products. The monoalkylated derivative [PPN][(CH3)2CH)NH2-12H11] (6, crystallized in the triclinic space group p1) and the bisalkylated product [PPN]{[(CH3)2NH—B12H11) (7, monoclinic, P21./c) were separated on the basis of their different water solubilities. The solid-state structures of the compounds 4-7 revealed a slight distortion of the B12 icosahedron. The length of the B(1)-N(1) bond was found to be dependent on the steric requirements of the attached amine, e.g. primary amine 〈 secondary amine 〈 tertiary amine. This is demonstrated by the variation in the B—N bond length; from 157.8(2) pm for 6, 158.5(5) pjm for 5, 160.0(3) pm for 7, to 163.7(6) pm for 4.
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  • 47
    ISSN: 0009-2940
    Keywords: Hexafluoroacetone ; Phosphorus, pentacoordinated ; Diphosphane diselenide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of the isoprene - PCl3 adduct 1 with magnesium powder, or with Si2Cl6, furnished P-chloro-3-methyl-phosphol-2-ene, 2, in satisfactory yield. Further reduction of 2 with Si2Cl6 gave the new trichlorosilyl-3-methylphosphol-2-ene, 3. The reaction of 2 with magnesium powder, with 3, or with 1/2 equivalent of Si2Cl6 provided the new γ3P-γP-diphosphane 1,1′-bi(3-methylphosphol-2-ene) 4. Reduction of 4 with Si2Cl6 led to 3. Oxidation of 4 with selenium gave the 1,2-diphosphane diselenide, 5. The oxidation of 4 with hexafluoroacetone led to a mixture of products, from which a novel tricyclic phosphorane 6 was separated. the structure of 196 was determined by X-ray diffraction; the coordination geometry at phosphorus in distorted trigonal bipyramidal, with a very long equatorial P - C(CF3)2 bond of 193.2(2) pm.
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  • 48
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 823-834 
    ISSN: 0009-2940
    Keywords: Phosphaalkynes ; Phosphaalkyne cyclotetramers ; Cage compounds ; Valence isomerization ; Cyclotetramerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In contrast to their all-carbon analogues, phosphaalkyne cyclooligomers only became accessible a few years ago. A milestone in the chemistry of cyclotetramers was the synthesis and structural characterization of the tetraphosphacubane 5, obtained as a thermolysis product of tert-butylphosphaacetylene (1). Since then, the construction of eleven cyclotetramers has been achieved, covering seven different frameworks (A-G). As a consequence of the use of kinetically stabilized phosphaalkynes as starting materials, all known cyclotetramers bear sterically demanding substituents (tert-butyl, tert-pentyl, 1-adamantyl). Cyclotetramerizations are not only achieved by thermolysis of 1, but also by alternative and selective routes such as transition-metal-mediated, Lewis acid- and base-induced processes, as well as by cycloadditions to phosphaalkyne cyclotrimers. Interestingly, these tetramers can be interconverted by various valence isomerizations. The results of thermal and photochemically-induced rearrangements are in good agreement with MO calculations carried out for the parent compounds. Phosphaalkyne cyclotetramers exhibit a highly interesting reactivity and other peculiar features. One outstanding example is the tetraphosphacubane 5, which shows unusual structural and spectroscopic properties as a result of its unique bonding arrangement.
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  • 49
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 843-849 
    ISSN: 0009-2940
    Keywords: P ligands ; Phosphorus heterocycles ; 2-Phosphanylphosphinines ; Dinuclear complexes ; Metal carbonyls ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2-phosphanyl-4,5-dimethylphosphinines 1-5 are powerful bridging ligands able to stabilize metal-metal single and triple bonds between low-valent transition metal centres. Their reaction with Mn2(CO)10 in refluxing xylene yields the corresponding Mn2(CO)8 complexes 6 and 7. Reaction with [Fe2Cp2(CO)4] under UV irradiation similarly yields the Fe-Fe-bridged Fe2Cp2(CO)2 complexes 8 and 9. An additional observation is that the 2-phosphininyl-3,4-dimethylphosphaferrocene 10 is formed upon reaction of the 2-phospholylphosphinine 5 with [Fe2Cp2(CO)4] at high temperature under CO pressure. A clean addition occurs at the Mo≡Mo triple bond of [Mo2Cp2(CO)4] to give the Mo-Mo single-bonded complexes 11-15. The thermolysis of these complexes succeeds when the phosphanyl group is a phosphonite P(OEt)2 (13) or P(OAr)2 (14), affording cleanly the Mo2Cp2(CO)4 triple-bonded complexes 16 and 17, respectively. The metal-metal triple bonds of these complexes readily add two molecules of CO to reform 13 and 14, or one molecule of tBu-N≡C to give 18 and 19. The X-ray crystal structure analysis of the MO2C2(CO)4 complex 13a, with the 2-P(OEt)2- phosphinine, shows a gauche orientation of the two Cp rings and very short P-Mo bonds of 2.3565(4) and 2.406(2) Å to the phosphinine and P(OEt)2 groups, respectively.
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  • 50
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1235-1240 
    ISSN: 0009-2940
    Keywords: Phosphorus ; Phase transitions ; Molecular crystal ; Crystal growth ; Low-temperature crystal structure ; Librational motion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: White phosphorus occurs in three modifications. The α form, which exists at roomtemperature, transforms reversibly to the β form at -77°C. The α · β transformation may be strongly delayed. Quenching the α form to -185°C followed by slow warming results in an exothermic reactions with formation of the γ form which transforms into the β form at -120°C in an endothermic reaction. A transition β · γ is not observed. The γ form is characterized by its powder diagram. The structure of the β form is redetermined from a single crystal at -185°C (P., α = 547.88(5), b = 1078.62(11), c = 1096.16(11)pm, α= 94.285(8), β = 99.695(7), γ = 100.680(7)., V = 623.79(10) · 106 pm3, Z = 6 formula units per cell). The P4 molecules exhibit pronounced librational motion in spite of the low temperature of investigation. The arrangement of the centers of the tetrahedra corresponds to the atom positions in the γ-plutonium structure, which is discussed in relation to the bcc structure.
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  • 51
    ISSN: 0009-2940
    Keywords: Asymmetric catalysis ; Cycloadditions ; Lewis acids ; Polymers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A dimethylpolysiloxane chain is covalently bound to the monomeric Lewis acid catalyst (1R)-(+)-oxovanadium(1V) bis[3- heptafluorobutanoylcamphorate] [(+)-5a] at the C-10 position of the camphor moiety yielding the novel chiral polymeric (1S)-( +)-oxovanadium(1V) bis[3-heptafluorobutanoylcamphorate] -dimethylpolysiloxane [( +)-6a][1]. The Lewis acid promoted hetero Diels-Alder reaction of trans-l-methoxy-3-(trimethylsilyloxy)- 1,3-butadiene (1) and benzaldehyde (2) is studied in the presence of the enantiomerically pure monomeric (5a, 5b) and polymeric (6a, 6b) catalysts. The monomeric and polymeric catalysts of identical chirality[1] invoke opposite enantioselectivities toward the formation of 2-phenyl- 2,3-dihydro-4H-pyrone (4). This remarkable result is corroborated by numerous control experiments. Thus, it is demonstrated that the environment of the active site of the catalyst is changed when the complex is fixed to a polymeric chain. In contrast to 5 and 6, the monomeric 12 and polymeric 13 europium(III) tris[3-heptafluorobutanoylcamphorates] of identical chirality invoke the same enantioselectivity toward the formation of 4. The concept of polymer attachment is utilized to recover the catalyst from the reaction mixture by precipitation and to recycle it for subsequent catalytic runs.
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  • 52
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 899-902 
    ISSN: 0009-2940
    Keywords: Cp3Zr complexes ; Cationic organometallic Lewis acid ; d0-Configured metal complex ; Acetonitrile ; crystal structure analysis of Zirconium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The organometallic salt [Cp3Zr(N≡C-CH3)]+ [CH3B-(C6F5)3]- (3a) has been prepared by treatment of Cp3ZrCH3 with B(C6F5)3 followed by the addition of acetonitrile. X-ray crystal structure analysis of 3a shows that its cation consists of three uniformly coordinated η5-cyclopentadienyl ligands about the zirconium atom. The acetonitrile ligand is end-on coordinated. In the linear [Zr] -N≡C-CH3 unit the C≡N triple bond [N-C2 1.126(5) Å] is slightly shorter than in the free acetonitrile molecule [dC≡N = 1.141(2) Å], the structure of which was determined as a reference by X-ray diffraction of a crystal obtained by IR-laser-induced zone melting on the diffractometer.
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  • 53
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 947-950 
    ISSN: 0009-2940
    Keywords: Copper ; N ligands ; Copper(I) complexes ; (Imine)copper(I) complexes ; Ketimines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of [(MeCN)4Cu]BF4 with two or three equivalents of benzophenoneimine lead to the formation of [(Ph2C=NH)2]BF4 (1) and [ (Ph2C=NH)3Cu]BF4 (2), respectively. A further equivalent of the ligand does not coordinate to the cation of complex 2. The crystal structures of both compounds were determined. 1 shows a linearly two-coordinated copper(I) center with a Cu-N distance of 1.877(2) Å. In compound 2 a distorted trigonal planar coordination of copper is observed with N-Cu-N angles of 114.5(2), 112.9(2) and 132.4(2)°, corresponding to two nearly equal Cu-N distances [Cu-N2 1.947(5) and Cu-N3 1.934(5) Å] dnd a significantly longer third one (Cu-N1 2.011(5) Å]. A comparison of these data with recently determined structures of bis(benzophenoneimine)silver(I) and -gold(I) complexes shows that the covalent radii of the monovalent coinage metals decrease in the order Ag(I) 〉 Au(I) 〉 Cu(I).
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  • 54
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Air oxidation of (Oxydi-2,1-phenylene)(2-phenoxyphenyl)stibane (1) gives the phenoxystibane oxide [(2-PhOC6H4)O(C6H4)2Sb]2O2 (2). Single crystals of (o-Tol2Sb)4- O4(O2)2 (3) were obtained by air oxidation of o-TolSb-(SiMe3)2. Crystal structures of 2 and 3 are reported.
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  • 55
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 975-980 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Phenoxide complexes ; Alkoxide complexes ; Terminal alkoxide ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The zinc hydroxide complexes Tp*Zn-OH of highly substituted pyrazolylborate ligands react with phenols, and alcohols, of sufficient acidity, in a condensation reaction with release of H2O. Starting with phenols the following were attached:phenolate, p-nitropehnolate, o-vanillinate, o-hydroxymethylphenolate, o,o-bis(hydroxymethyl) -p-methylphenolate. Whilst aliphatic alcohols and benzyl alcohol did not react, their derivatives, with highly electronegative substituents could be incorporated. Thus, the arylmethoxides OCH2C6F5 and OCH2C6H4NO2-p, as well as the alkoxides OCH2CF3 and OCH2CCl3, were attached. 2-Mercaptoethanol was bound via its thiolate function. The crystal structures of TpCum,Me ZN-OC6H4NO2-p,TpCum,Me ZN-OCH2-C6F5, TpCum,Me ZN-OCH2CF3, TpCum,Me ZN-OCH2CCl3 and TpCum,MeZn-SCH2CH2OH were determined.
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  • 56
    ISSN: 0009-2940
    Keywords: Platinum ; Nitrocyanamide ; Nitrosodicyanomethanide ; 1,1,3, 3-Tetracyano-2-azapropenide ; 1,1,2,3,3-Pentacyanopropenide ; Hydrido complexes ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new coordination compounds trans-[Pt(H)X(PPh3)2] with NCN- and C(CN)2-functionalized anions (X- = [N(O)C(CN)2]-, [NO2NCN]-, [N{C(CN)2}2]-, [NCC{C-(CN)2}2]-, have been characterized by 1H-, 31P-, 13C-NMR, and IR spectroscopy and elemental analyses the crystal structures of trans-[Pt(H)N(O)C(CN)2(PPh3)2], trans- [Pt(H)N{C(CN)2}2(PPh3)2], and trans-[Pt(H)NCC{C(CN)2}2-(PPh3)2) have been determined by X-ray diffraction. Remarkably, [N(O)C(CN)2]- is coordinated through the central nitrogen atom, while [N{C(CN)2}2]- and [NCC(C(CN)2]2]- are bonded through terminal nitrogen atoms of a C(CN)2 unit.
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  • 57
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1021-1027 
    ISSN: 0009-2940
    Keywords: Zinc ; Chirality ; Cross-coupling ; Phosphorylations ; Catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This Microreview on the chemistry of organozinc reagents starts by briefly showing the methods of preparation of organozinc compounds and then discusses the considerable synthetic utility of zinc organometallics for the formation of new carbon-carbon bonds in the presence of transition-metal catalysts. Finally, the use of organozinc chemistry for the preparation of polyfunctional and chiral phosphanes is described.
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  • 58
    ISSN: 0009-2940
    Keywords: Bis(tetramethylipiperidino)aluminum halides ; Alkoxy((tetramethylpiperidino)aluminum halides ; 27Al-NMR spectra ; Aluminum ; Amides ; Synthetic methods ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Lithio-2,2,6,6-tetramethylpiperidine [Li(tmp)] reacts with AlX3 (X = Cl, Br) in diethyl ether/ n-hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ-OEt)], (la, X = Cl; 1b, X = Br). However, when the reaction is allowed to proceed in n-hexane alone, an almost quantitative yield of compounds tmp2AlX (2a, X = Cl; 2b, X = Br; 2c, X = I) is obtained. According to 27AI-NMR spectroscopy, mass spectroscopy, cryoscopy, and X-ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF4 yielding the fluoride-bridged dimer (tmp2AlF), 2d, as shown by X-ray crystal structure determination.
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1461-1465 
    ISSN: 0009-2940
    Keywords: Kolbe-Schmitt reaction ; Solid-state structures ; Sodium phenoxide ; Solvent Complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solvent-free sodium phenoxide (NaOPh) crystallises as a polymer and forms a polymeric chain in the [0 0 1] direction. The low coordination of the sodium atoms, as evident in the crystal structure, is confirmed by the easy coordination of oxoligands (α-donors). Hence, the four-membered ring chain of the solvent-free sodium phenoxide is separated by oxoligands, and forms partial structures as the polymer fragments. Thus, NaOPh crystallises in THF with the formation of an Na6O6 core, consisting of two face-fused heterocubes, and in N, N, N′, N′-tetramethyl urea (TMU) with the formation of a Na4O4 heterocubane. The solvent-free NaOPh-CO2 complex obtained from the addition of CO2 to a solution of sodium phenoxide is, when exposed to a temperature of 80°C, subject to an irreversible phase transition, as demonstrated by FT-IR and DTA studies. The complex formed at 80°C is, apparently, another intermediate of the Kolbe-Schmitt reaction.
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  • 60
    ISSN: 0009-2940
    Keywords: Naphthalenes ; Phosphanes ; Phosphorus heterocycles ; Protecting groups ; Strained molecules ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1.8-dilithionaphthalene 1 reacted with bis(dimethylamino)-chlorophosphane to form 1,8-bis[(diethylamino)phosphanyl]-naphthalene 2, whose structure was confirmed by X-ray crystal structure analysis; there are two independent molecules, in which the P(NEt2)2 groups adopt an eclipsed conformation. Reaction of 2 with gaseous HCl gave in low yield 1,8-bis-(dichlorophosphanyl)naphthalene 3, which was characterized by 1H- and 31P-NMR spectroscopy, mass spectrometry and elemental analysis. Attempted recrystallization of 3 led to oxidative hydrolysis which furnished 4, an anhydride of a bis(chlorophosphonic acid), whose structure was elucidated by X-ray crystal structure analysis. The geometry of 4 reveals a relief of strain from the bis (aminophosphane) 2; the naphthalene groups are less distorted and the P atoms are displaced less far from the naphthalene best plane.
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  • 61
    ISSN: 0009-2940
    Keywords: Gold ; Silver ; Diphosphane ; Diphosphane Disulfide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinylidenebis(diphenylphosphane) reacts with gold(I) or gold(III) compounds to give dinuclear {[{Au(C6F5)]2[(PPh2)2C=CH2{] or [Au{PPh2C(=CH2)Ph2P)]2(ClO4)2] or mononuclear complexes ([Au(C6F5)3(PPh2C(=CH2)Ph2P)]}, respectively. The latter reacts with gold(I) or silver(I) compounds to afford dinuclear [[Au(C6F5)3[PPh2C(=CH2)Ph2P}AuX], X=Cl or C6F5) or trinuclear species {[{Au(C6F5)3{PPh2C(=CH2)Ph2P{]2M]ClO4, M=Au or Ag}. No addition of nucleophiles to the C=C double bond is observed in these complexes, which contain the diphosphane acting as bridging or monodentate ligand. (SPPh2)2C=CH2 reacts with AgClO4 to give [Ag{SPPh2C(=CH2)Ph2PS}]2-(ClO4)2or[Ag[PPh2C(=CH2)Ph2P]2]ClO4. The crystal structure of [Au(C6F5)3{PPh2C(=CH2)Ph2P}Au(C6F5)] has been established by X-ray crystallography, and confirms the expected square planar and linear geometry for the Au111 and Au1 centres, respectively.
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  • 62
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1547-1550 
    ISSN: 0009-2940
    Keywords: Phosphane ; 1,3α., 5,7β-Tetrakis(trifluoromethyl)-6,-9-dioxa-2-phosphabicyclo[3.3.1]nonane-3β, 7α-diol ; 1,7-Trifluoromethyl-3,5-methyl1-2,4.8-trioxa-6-phosphaadamantane ; Phosphorus heterocycles ; Ketones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A two-step formal insertion of 1,1,1,5,5,5-hexafluoro- (2a) and 1,111-trifluoropentane-2,4-dione (2b) into the P-H bonds of phosphane gave the primary a-hydroxyphosphanes 3 and 4, precursors for the resulting secondary phosphanes, 6,9-dioxa-2-phosphabicyclo[3.3.l]nonane (6a) and 2,4,8-trioxa-6-phosphaadamantane (7), both formed diastereospecifically. The molecular structures of 6a and 7 were established by single-crystal X-ray structure analysis which revealed two independent molecules for 6a in the unit cell possessing a chair-boat conformation with a C-P-C angle of 95.4(2)°, and a characteristic heteroadamantane geometry for 7, with the corresponding angle being smaller by 4.9°.
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  • 63
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1605-1609 
    ISSN: 0009-2940
    Keywords: Axial-chiral complexes ; Biaryls ; Carbene complexes ; Circular dichroism ; Chromium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Axial-chiral mono- and biscarbene complexes of chromium containing the 1,1-binaphthyl skeleton have been obtained in both racemic and enantiopure forms in a one-pot reaction starting from lithiated 2,2-dimethoxy-1,1-binaphthyl (1) and hexacarbonyl chromium via the Fischer route. An X-ray structure analysis of the biscarbene complex 2 reveals that the biscarbene functionalization significantly increases the dihedral angle defined by the biaryl planes. The enantiopure complexes have been characterized by CD spectroscopy.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1261-1267 
    ISSN: 0009-2940
    Keywords: Single-component metallocene catalyst ; Olefin insertion ; Organometallic ions pairs ; (Alkene)metallocene complex ; Metallocene betaines ; C-C coupling ; Zirconium ; Homogeneous catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of the (butadiene)ML2 complexes 1 [ML2 = Cp2Zr (a), Cp2Hf (b), and (.-C5H4CH3)2Zr (c)] with B(C6F5)3 gives the 1:1 addition products (CH2CHCHCH2-B(C6F5_3)ML2 (3a-c). At -40°C the betaine complex 3a inserts one equivalent of methylenecyclopropane to give the regioisomeric insertion products 5a and 6a in a 60:40 ratio. These products exhibit the cyclopropylidene moiety in the α- and β-positions, respectively, relative to zirconium. The corresponding hafnocene complexes 5b and 6b are obtained in a 70:30 ratio starting from 3b. The reaction of 3(a-c) with allene gives a single insertion product (7a-c) in each case where the exo-methylene group is in the α-position to the metal center ([2,1]-insertion). The complexes 5-7 are chiral. They all exhibit a pronounced ·-interaction of the internal -C4H=C5H- double bond of the s̰-ligand chain with the metal center in addition to a metallocene/-C6H2-[B] ion pair interaction. The relative contributions of the cationic metallocene end of the dipolar complexes 5-7 are quite dependent on the steric and electronic properties of the respective metallocene units involved. This is revealed by a comparison to typical 13C-NMR parameters of the complexes 5-7 with a pair of suitable model complexes, namely the ethylene insertion product 4 into the betaine system 3a and its THF adduct 4.THF.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1279-1294 
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Aminolytic cleavage of oxetanes ; Tripod molybdenum compounds ; Mixed donor set ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of neopentane-based tripod ligands CH3C(CH2X)(CH2Y)(CH2Z( 3 (X = NR2, NHR; Y = PR2; Z = PR2, SR, S-) in a convergent manner is described. The procedure is based on the aminolytic cleavage of functionalized oxetanes CH3C(CH2OCH2)CH2R 1 by primary or secondary amines, leading to functionalized amino alcohols CH3C(CH2NHR)(CH2OH)(CH2R) or CH3C(CH2NR2)-(CH2OH)(CH2R) 2. The appropriate activation of the R (e.g. OR) and OH groups present in 2 allows for substitution vs. SR or PR2 donor functions. Depending on the nature of the groups present in each reaction step, various protection and groups present in each reaction step, various protection and deprotection steps have to be taken in the course of this type of preparation of the tripod ligands 3. By reaction with (CH3CN)3Mo(CO)3, ligands 3 form Mo(CO)4 derivatives 4 or Mo(CO)3 derivatives 5, depending on the reaction conditions. In compounds 4, the ligands are coordinated in a bidentate mode with the soft donor atoms (P, S) coordinated and the hard donor function playing the role of the dangling arm. In the trihapto bonding mode present in 5, all three donor functions, two soft (P, S) and one hard (NHR′, NR′2), are coordinated. The two types of coordination compounds may be interconverted: 4e (X = NMe2′ Y = PPh2, Z = SiPr) with a non-coordinating CH2NMe2 group is transformed into 5c upon photolytic decarbonylation. Under 1 bar CO at 20°C, 5c reverts to 4e. X-ray structure analysis of a series of compounds of types 4 and 5 reveals characteristics of the relevant conformational patterns. All compounds have been fully characterized by the standard analytical techniques (NMR, MS), as well as elemental analysis.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1333-1338 
    ISSN: 0009-2940
    Keywords: Gold ; Gold(I) complexes ; Phosphinite complexes ; Phosphite complexes ; Configuration determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of compounds (R3P) AuMe with diphenylphosphinous acid Ph2P(O)H affords methane and neutral complexes of the type (R3P(O)Ph2 (1a: R = Me; 1b: R = Ph, lc: R = o-Tol). 1a, b are obtained in high yield, but the yield of lc is lower owing to a side-reaction which leads to a different product: Ph2P(OH)-Au-P(O)Ph2 (2). The crystal structure of 1a was determined by a single-crystal X-ray diffraction study. The compounds is a monomer with a linear P-Au-P′ axis and the phosphane and phosphinite ligands in a staggered conformation. In solution (CHCl3, CH2Cl 2/) compounds 1a-c undergo a ligand redistribution, establishing equilibria that involve ionic isomers of the type [R3P)2Au]+ [Au-(P(O)Ph2)2]-, which are readily identified through their NMR data. The analogous reaction of (R3P)b AuMe with dimethylphosphite (MeO)2P(O)H gives methane and the corresponding dimethylphosphites of the type (R3P)AuP(O)(OMe)2 (3a: R = Me; 3b: R = Ph; 3c: R= o-Tol). The crystal structure of 3b has also been determined. It features a linear structure with an eclipsed conformation of the ligands. In polar solvents (CHCl3, methanol) there is again an eqilibrium between neutral and ionic isomers, the latter comprising bis(phosphane)gold cations [(R3P)2Au]+ and {Au[P(O)-(OMe)2]2)- anions, as confirmed by NMR spectroscopy and mass spectrometry.
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  • 67
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1353-1359 
    ISSN: 0009-2940
    Keywords: 113Cd NMR ; Multidentate ligand ; Multinuclear metal complex ; Piperazine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eleven novel piperazine containing open-chain ligands L1-L11 were designed to offer symmetrical and asymmetrical complexation sites for metal ions and were synthesized by repetitive synthetic method. The divergent use of aromatic bishalomethyl and mono-N-alkylated piperazine compounds as spaces led toa series of long (up to M. W. = 836) oligomeric multidentate N-ligands. Due to the lack of solid state methods for structure analysis, an NMR technique using 113 Cd nucleus as a probe in solution state was utilised. 113 Cd chemical shifts were observed to be dependend on the coordination site and similar coordination sites in different ligands gave characteristically similar 113 Cd chemical shifts. As a result 113 Cd-NMR spectroscopy proved to be an excellent tool to distinguish between the structures of the different complexation sites on a nearly quantitative level.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1365-1374 
    ISSN: 0009-2940
    Keywords: N ligands ; Chelates ; Coordination modes ; Ligand effects ; Structure-activity relationships ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monoanionic bi- and tridentate ligand systems emulating the structural features of the well-known poly(pyrazolyl)borates are created by bridging heteroaromatic rings with formally negatively charged p-block elements. Their properties and versatility are exemplified by their complexes with main group metals. Due to their N(σ)-donating and π-interacting ability, as well as the flexibility of the substituent bonding, these ligand systems have the potential to adapt both geometrically and electronically to the coordination requirements of the complexed metal. Within these complexes, the heteroaromatic substituents operate as charge spacers between the formally anionic center and the metal cation without encapsulating either site. This provides possible applications in the creation of reactive soft/hard bimetallic reagents, the realization of multinuclear arrays, and the design of preorganized CVD precursors, particularly en route to III/V-semiconducting thin films.
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  • 69
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1411-1416 
    ISSN: 0009-2940
    Keywords: Phosphane-boranes ; Boranes ; Phosphanes ; Umpolung, attempted ; Bond polarity ; Configuration determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of (Me2S)BH2Br and (Me2S)BHBr2 with equimolar quantities of 1,2-bis(diphenylphosphanyl)ethene (1) or -benzene (2) lead to cyclic, cationic bis(phosphane)boranes [4[(1)BH2]+ Br-; 6: [(2)BH2]+ Br; 7: [(2)BHBr]+ Br-]. The Br counterions can be exchanged in metathesis reactions (e.g. with AgBF4 to afford 4a). The tritertiary phosphane bis[2-(diphenylphosphanyl)phenyl]phenyl-phosphane (3), reacts with (Me2S)BHBr2 to give bicyclic dicationic tris(phosphane)borane 8, [(3)BH]2+ Br-, which can be converted into the bis(hexafluorophosphate) 8a using NH4PF6. All compounds have been characterized by analytical and NMR-spectroscopic data. The crystal and molecular structures of 5 - 7 have been determined by single-crystal X-ray diffraction. The five-membered rings C2P2B have an envelope conformation and show no sign of electron delocalization. Attempts to deprotonate the B—H functions in 5 - 8 have not been successful. Clearly, the two (5 - 7) or three phosphonium centers (8) adjacent to the boron atom are not sufficient to induce an “umpolung” of the B—H group
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  • 70
    ISSN: 0009-2940
    Keywords: Metal - metal bonds ; Insertion reactions ; Group-13 monochlorides ; Main-group elements ; Nickel ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dinuclear compound [{(η5 - Cp)Ni(PEt3)}2] (1) containing an unbridged Ni-Ni bond reacts with the heavier group 13 monochlorides [{CH(SiMe3)2)2}AlIIICl], InCl, and TlCl by scission of the metal-metal bond. In the case of InCl and TlCl the chloro-bridged dimmers [{(η5-Cp)Ni(PEt3)2ECl2Ecl}2] (E = In 2, Tl 5) were formed. The Tl compound 5 is unstable and decomposes via disproportionation a and formation of the halogen-free Tl [III] compound [{(η5-Cp)Ni(PEt3)}3Tl] (6). 2 can be dehalogenated with activated magnesium to yield the halogen-free In [III] compund [{(η5-Cp}Ni(PEt3)}3In] (4). The Ga analogue of 4 and 6 [{(η5-Cp)Ni(PEt3)}3Ga] (7) is accessible by a conproportionation of 1 with Ga metal in refluxing THF. In contrast to InCl and TlCl the aluminium (III) monochloride [{CH(SiMe3)2}2AlCl] reacts with 1 by a ligand redistribution reaction and formation of the salt [{(η5-Cp)Ni(PEt3)2]+-[{CH(SiMe3)2]2AlCl]2-. (8). Elemental Hg or Mg amalgam show the same activity as elemental Ga towards 1 and insert into the Ni—Ni bond by forming the linear Hg-bridged complex [(n3-Cp)Ni(PEt3)]2Hg] (9). The molecular structures of 2, 4, 8, and 9 were determined by X-ray crystallography. The In atom in 4 has a distorted trigonal-planar configuration with the central In atom being surrounded by three [(n5-Cp)Ni(PEt3)] fragments. 4 represents the first Ni-In cluster containing exclusively unsupported In - Ni bonds, as well as the first carbonyl-free Ni - In cluster. On the basis of spectroscopic data the same structure is assigned to the Ga and Tl analogues of 4. The Ni—Hg—Ni arrangement in 9 is exactly linear, as determined by X-ray crystallography.
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  • 71
    ISSN: 0009-2940
    Keywords: Schiff bases ; Polyene dialdehydes ; α-Amino acids ; Pantamethylcyclopentadienyl complexes ; P ligands ; Iridium ; Palladium ; Platinum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Schiff bases 1—11 were synthesized from α-amino acids or o-aminophenol and crocetindialdehyde, 2,7-dimethyloctatrienedial, terephthalaldehyde, or β,β′ -p-phenylendiacroleine. The reactions of these Schiff bases with chloro-bridged complexes [(R3P)(Cl)M(η-Cl)]2 (M = Pd, Pt) and [(C5Me5)(Cl)Ir(°Cl)]2 gave the dinuclear complexes 12-31.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1495-1498 
    ISSN: 0009-2940
    Keywords: Deltacyclenes ; Deltacyclanes ; P-H addition reactions ; Chiral phosphanes ; Enantioselective catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The suitability of enantiomerically pure deltacyclenes as building blocks in the synthesis of expanded phosphanes was examined. Different substituted deltacyclenes were irradiated with diphenylphosphane and three bisphosphanyl derivatives. With these P—H addition reactions, new chiral deltacyclane-derived phosphorus ligands were synthesized. They were tested in the Rh-catalyzed asymmetric hydrogenation of (Z)-(ã)-N-acetamidocinnamic acid and in the Pd-catalyzed asymmetric allylation of 1,5-dimethylbarbituric acid.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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    Topics: Chemistry and Pharmacology
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  • 74
    ISSN: 0009-2940
    Keywords: Chromium ; Chromium(0) complexes ; Cyclooctatetraene complexes ; Photochemistry ; Cycloadditions ; Photochemical [6+2] cycloadditions ; Dienes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tricarbonyl(η6-1,3,5,7-cyclooctatetraene)chromium (1) yields upon UV irradiation in ether at 233 K with 2,3-dimethyl-1,3-butadiene (2) or 2-methyl-1,3-butadiene (3) by [6+2] cycloadditions the correspondingly substituted tricarbonyl(η6-bicyclo[4.2.2]deca-2,4,7-triene)chromium complexes 4, 5a and 5b. With ammonium cerium(IV) nitrate the organic ligand of complex 4, 9-isopropenyl-9-methyl-bicyclo[4.2.2]-deca-2,4,7-triene (6) is liberated. The complexes 4, 5a and 5b were characterised by IR and NMR spectroscopy, the ligand 6 by NMR spectroscopy.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 49-54 
    ISSN: 0009-2940
    Keywords: 4-(p-Bromoselenobenzoyl)morpholine ; 4-[(p-(Dimethylamino)selenobenzoyl]morpholine ; Hindered rotation ; Hammett treatment ; Selenoamides ; Amides ; Selenium compounds ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solid-state structures of (p-bromoselenobenzoyl)morpholine (2a) and [p-(dimethylamino)selenobenzoyl]morpholine (2b) were determined by X-ray diffraction. Both molecules show a flat selenoamide group. The larger contribution of resonance stabilization by the aromatic ring carrying the p-dimethylamino substituent is reflected by the smaller interplanar angle Θ between the aromatic ring and the selenoamide group [53.3(1)° vs. 81.1(1)°] and by the shorter length of the C=Se bond [1.824(5) Å vs. 1.840(3) Å]. The Gibbs free energy of activation of C-N bond rotation (ΔG≠rot) of five p-substituted (selenobenzoyl)morpholines was determined by dynamic 13C NMR. The activation barriers were found to range from 61.6 kJ/mol (X = NNMe2) to 75.1 kJ/mol (X = H). The ΔG≠rot values of the corresponding (thiobenzoyl)morpholines were found to be from 3.2 kJ/mol (X = NMe2) to 5.0 kJ/mol (X = H) lower. In both cases, ΔG≠rot showed an excellent linear Hammett correlation with s̰+p.
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  • 76
    ISSN: 0009-2940
    Keywords: Lithium ; Zine ; Dibenzylzinc ; Tmeda complexes ; Heteroleptic alkylzinc amide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of lithium phenyl(trimethylsilyl)methanide with phenyl(trimethylsilyl)methylzinc chloride-tmeda in the presence of tmeda yields the addition product, a bis(tmeda)-lithium dialkylchlorozincate. The elimination of lithium chloride leads to the formation of a tmeda adduct of bis[phenyl-(trimethylsilyl)methyl]zinc. The metathesis reaction of phenyl(trimethylsilyl)methylzinc chloride-tmeda with lithium tris(trimethylsilyl)silylamide allows the isolation of the corresponding heteroleptic tmeda complex of an alkylzinc amide. The metalation of phenyl(trimethylstannyl)methane with butyllithium yields the transmetalation product benzyllithium. From the metathesis reaction of this lithium base with anhydrous zinc(II) chloride in the presence of tmeda, the tmeda adduct of dibenzylzinc crystallizes. The molecular structures of (tmeda)Li—CH(GeMe3)Ph, (tmeda)Zn(CH2Ph)2, (tmeda)Zn[CH(SiMe3)Ph]2, and (tmeda)Zn[CH(SiMe3)-Ph[N(H)Si(SiMe3)3 are reported. Whereas lithium bonds in an η3-fashion, the zinc atom forms a σ(Zn—C) bond. The extremely wide Zn—N—Si angle in (tmeda)Zn[CH(SiMe3)-Ph[N(H)Si(SiMe3)3 of 157° is remarkable.
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  • 77
    ISSN: 0009-2940
    Keywords: Rhodium ; Chelate complexes ; Hydrido complexes ; Bridging ligands ; P Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mononuclear starting materials [Rh(η4-C8H12)(k2-P,Sb-iPr2PCH2SbR2)]PF6 (la, b) react with CF3CO2H in the presence of H2 to give the dinuclear hydridorhodium(II1) complexes [{RhH(k2-P,Sb-iPr2PCH2SbR2)]PF6 (2a, b) in almost quantitative yield. The X-ray crystal structural analysis of 2b (R = tBu) reveals a distorted octahedral geometry around the two metal centers with the two phosphanyl(stibanyl)methanes in a chelating and the two trifluoracetate ligands in a bridging coordination mode.
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1551-1555 
    ISSN: 0009-2940
    Keywords: Antitumor agents ; Nucleotides ; Palladium ; Hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The compound [Pd(en)(5′-IMP-N7)2].11 H2O, where 5′-IMP = inosine 5′-monophosphate, crystallizes in the tetragonal space group P4322 with the unit cell parameters: a = b = 12.060(5) and c = 28.510(5) Å, V = 4147(3) Å3, Z = 4. A head-to-tail orientation with A configuration is observed for the nucleotides which are coordinated through the N(7) positions such that d[Pd-N(7)] = 2.053(8) Å. The sugar moieties exhibit anti orientations toward the purine bases while their pukkers adopt C(3)′-endo conformation. The overall conformation about the phosphate backbone is gauche+. Intramolecular hydrogen bonding is observed between the phosphates and the NH groups of the en ligand with a donor-acceptor distance of 2.88 Å. The coordination mode of the solid-state structure is shown to be identical to that observed by 1H-NMR spectroscopy in solution under slightly acidic conditions, where the N (l) positions of the nucleotides are protonated. The results are discussed in reference to closely related systems reported in the literature with emphasis on the importance of hydrogen bonding in such complexes.
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  • 79
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1579-1583 
    ISSN: 0009-2940
    Keywords: Silatetrazenes ; Nitrogen-silicon ring systems ; Bissilylamines ; Silicon-29 solid state NMR ; Aryl azides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction between aryl azides and lithiated aryl amines leads to tetrazenes 3 and 9 which contain a chain of four nitrogen atoms. Reaction with different halosilanes gives the cyclic silatetrazenes 10, 12, and 15 where substitutents on the silicon vary form alkyl to hydrogen and chlorine atoms. The structures of 10, 12, and 15 in the solid state are reported. Variation of the solvent and the Lewis acidity of the halosilane influence the ratio of silatetrazene to side products, bissilyated amines. These effects are studied for different halosilanes.
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  • 80
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 135-140 
    ISSN: 0009-2940
    Keywords: Synthesis ; Phosphorus ; Supersilyloligophosphides ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of P4 in THF or DME with 2 R*Na (R* = SitBu3) at -78°C leads quantitatively to deep red THF or DME adducts of R*NaP-P=P-PNaR* (3). According to 31P NMR, the P4 skeleton 3 is cis-configurated. On the other hand, reaction of P4 in TBME with 2 R*Na at -78°C leads quantitatively to (R*NaP)4 (4), a [2+2] cycloadduct of 3, the Na4P8 skeleton of which according to X-ray structure analysis forms a double cube with four P atoms in the second layer and two P and two Na atoms in alternating positions in the first and in the third layer (the Na atoms are coordinated with donors). By resolving the THF adduct 3 in TBME (the TBME adduct of 4 in THF) the compound 4 (the compound 3) is rapidly formed under reversal of the P-P=P-P configuration by way of [2+2] cycloaddition (by way of [2+2] cycloreversion). 3 and 4 are sensitive to oxidation and to protolysis. With TCNE, 3 is oxidized to R*2P4 (bicyclic P4 skeleton), with CF3SO3H, 3 may be transformed into R*3P5Na2 X 4 THF or in (R*P3)3 and R*PH2.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 155-159 
    ISSN: 0009-2940
    Keywords: Cyclopentadienes ; Metathesis ; Potassium ; Calcium ; Main-group elements ; Sandwich complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclopentadienyl ring metathesis occurs between [Ca(C5Me5)2] and [Ln(C5H5)3] complexes in toluene to generate the mixed ring compounds [Ln(C5Me5)2(C2H5)] (Ln=1-La, 1-Nd). 1-Nd has been characterized with X-ray diffraction as a sterically crowded monomer. Only one ring is exchanged between [Ca(C5Me5)2(thf)x] and [La(C5H5)3(thf)x] in toluene to yield [La(C5Me5)C5H5)2 (thf)] (2). In reaction with [M(C5H5)2] (M=Sn, Pb, Mn), [Ca(C5M5)2(thf)x] yields the corresponding [M(C5Me5)2] complexes. K[C5Me5] reacts with [La(C5H5)3(thf)], [Sn(C5H5)2] and [Pb[C5H5)2] in toluene to yield the ring-exchanged products 2, [Sn(C5Me5)2], and [Pb(C5Me5)2], respectively.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 195-199 
    ISSN: 0009-2940
    Keywords: Titanium ; Enolates ; Kinetics ; Enols ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of various sterically congested sodium enolates, generated by quantitative deprotonation of stable enols (of diphenylacetaldehyde in the case of 5), with dichlorotitanocene afforded a series of novel titanium enolates 1-5. The crystal structure of 1 could be determined. Due to the considerable steric shielding of the β,β-diaryl moiety, all the titanium enolates exhibit an oustanding stability towards hydrolysis, which increases with the higher steric demand of the substitutents at the C-C double bond. The kinetics of the hydrolysis, which is pseudo-first-order in THF/water (1 : 1) and acetonitrile/water (1 : 1), was investigated by UV spectroscopy. The pseudo-first-order rate constants measured in these solvent mixtures are in the range 6.4 · 10-4 s-1 〈 k1 〈 1.1 · 10-3 s-1. For comparison, the hydrolysis of 6, which should exhibit the usual sensitivity of titanium enolates towards hydrolysis, is about 1000 times faster.
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  • 83
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 217-219 
    ISSN: 0009-2940
    Keywords: Gold compounds ; (Phosphane)gold(I) complexes ; Clusters ; P Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenylene-1,2-bis(phosphane) reacts with two mole-equivalents of tris[(triphenylphosphane)gold(I)]oxonium tetrafluoroborate in dichloromethane at -78°C to give high yields of a hexanuclear complex {C6H4]P(AuPPh3)3]2}2+ · 2 BF-4 (1). The variable-temperature 31P{1H}-NMR spectra of the product in CD2Cl2 at - 80°C are compatible with a static structure featuring three Ph3PAu units associated with each of the two C6H4P2 phosphide functions, as derived from a clear doublet/quartet pattern. At 50°C in CDCl3, however, there is rapid intramolecular scrambling of these Ph3PAu units, which gives rise to a triplet/septet pattern with the J(P,P) value reduced to exactly one half of the value at the low temperature limit.
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  • 84
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 235-239 
    ISSN: 0009-2940
    Keywords: Iron-sulfur cluster ; Mixed halide ligands ; Magnetic properties ; Clusters ; Iron compounds ; Sulfur compounds ; Halogen compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization of the new mixed-halide clusters (Et4N)2[Fe2S2Cl4-nBrn] (n=2, 3), together with an improved synthesis of (Et4N)2[Fe2S2Br4] and the crystal and molecular structure of (Et4N)2[F2S2Cl2Br2], are reported here. The structure consists of [Fe2S2Cl2Br2] dianions, with a pseudo-tetrahedral symmetry around each iron atom. A disorder problem precludes precise identification of the locations of the chloride and bromide ligands. A syn (or anti) conformation is however considered to be most likely, for steric hindrance reasons and on the basis of Mössbauer data. The Mössbauer, magnetic susceptibility, cyclic voltammetry and UV/Vis properties of the new clusters remain similar to those of the parent single-type halide clusters. These new clusters are interesting precursors for complexes with mixed thiolate and non-thiolate coordination at the iron sites.
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  • 85
    ISSN: 0009-2940
    Keywords: Calix[4]resorcinols ; Dioxaphosphocins ; Supramolecular chemistry ; Solid-state NMR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterisation of the reactive tetrakis (O,O-phosphorus)-Bridged calix[4]resorcinols 3 and 4 is described. Because of its poor solubility in common organic solvents, a solid-state NMR investigation of 3 (1H, 13C, 31P) was conducted. Reaction of 3 with MeMgl, Me3 SiMNe2, and HNMe2 furnished the η3γ3P-substituted cavitands 5 and 6. Oxidative addition reactions of 6 with the (H2N)2C(=O)/H2O2 (1:1) adduct, tetrachloro-o-benzoquinone (TOB), and hexafluoroacetone (HFA) led to the η4γ5P derivative 7, and to the η5γ5P derivatives 8 and 9. An X-ray crystal-structure determination of the tetrakis(O,O-phosphorus)-bridged calix[4]resorcinol 4 has been conduced. The framework displays the cone conformation; the chlorine atoms are directed inwards.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1739-1744 
    ISSN: 0009-2940
    Keywords: Carbon nitride ; Tetra(amino)methanes ; Guanidinium salts ; Amination ; Conformation analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Because of their possible role as model compounds for the structural units of carbon nitride C3N4, the preparation, structural chemistry, and some representative reactions of tetra(amino)methanes have been (re)investigated. In the crystal, C(NMe2)4 (1) has a molecular geometry close to D2a symmetry as proposed by theoretical calculations using state-of-the-art density functional methods. The coordination of the central carbon atom is distorted tetrahedral and the configuration of the nitrogen atoms is strongly pyramidal, as opposed to almost planar in the tetra(amino)silanes. Tetra(pyrrolidinyl)methane has a similar core structure, with all heterocyclic substituents in an envelop conformation flexible in solution. Tetra(piperidinyl)methane is more rigid in solution, owing to a more congested structure, with much higher inversion barriers for the six-membered rings. Hydrolysis of 1 leads to MezNH and hexamethylguanidinium hydroxide, and treatment of 1 with HAuCl4(aq) affords crystalline [C(NMe2)3]4 AuCl4- the structure of which has also been determined. Compound 1 is a strong nucleophile and can be used as an aminating agent, converting e.g. halosilanes into dimethylaminosilanes, with the guanidinium cation as the leaving group. The experimental results are discussed in the light of recent predictions regarding bulk carbon nitrides.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1765-1770 
    ISSN: 0009-2940
    Keywords: Phosphinic acid ; Phosphaindole bromination and chlorination ; Layer structure ; Hydrogen bonds ; Bromine-bromine interaction ; Phosphorus heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bromination of 1-ethoxy-1-oxophosphindolin-3-one (1) with two equivalents oi bromine occurs with elimination of hydrogen bromide and ethyl bromide, providing 2,2-di- bromo-1-hydroxy-1-oxophosphindolin-3-one (4) in high yield. In the presence of triethylamine this process leads to 2,2-dibromo-1-ethoxy-1-Oxophosphindolin-3-one (3) instead. Triethylamine deprotonates 4, providing the solid triethylammonium salt 5. Silylation of 4 with chlorotrimethylsilane leads to the trimethylsilyl ester 6. Monobromination in a two-phase reaction allows the isolation of a mixture of isomers of 2-bromo-1-ethoxy-1-oxophosphindolin-3-one (2a, b). Chlorination with chlorine furnishes 2,2-dichloro-1-ethoxy-1-oxo-phosphindolin-3-one (7). The new compounds 2-7 were characterized analytically and spectroscopically (EI-MS, 1H, 13C and 31P NMR). The crystal structure of acid 4 was determined by X-ray diffraction. Solid 4 consists of aryl stacks connected by chains of P—OH…O==P hydrogen bonds and secondary Br…Br contacts.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1791-1799 
    ISSN: 0009-2940
    Keywords: Platinum substitution ; Metal-carbon bonds ; trans-Labilization ; Kinetics ; Activation parameters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The substitution reactions of cis-[PtMe,(dmso),] with pyridine (py) to produce cis-[PtMe2py2] in toluene proceeds in two steps. In the absence of added dimethylsulfoxide (dmso), these steps can not be separated due to the rate constants being very similar. In the presence of added dmso, the rate of the first step, the formation of the monopyridine complex is retarded, which is indicative of a dissociative mechanism. A parallel associative reaction path with pyridine could also be observed. This pathway is independent of the concentration of added dmso. Above a 40-fold excess of dmso, the dissociative pathway is suppressed and only the associative reaction occurs. A plot of Kobs vs the pyridine concentration for this pathway is linear at low [py], but shows a saturation at high [py]. This suggests that the reaction occurs via the formation of a precursor-complex, for which the formation constant was found to be 0.32 · 0.03 M-1. The volume of activation at a high pyridine concentration is -11.4 · 0.8 cm3 mol-1, which indicates that the ligand interchange process is of the associative type. The second step, the formation of the bispyridine complex, can clearly be separated from the first reaction step. This step occurs via a dissociative mechanism, as demonstrated by the decrease in kobs with increasing pyridine concentration. The dissociation of dmso was characterized by a rate constant of (8.1 · 0.9).10-45-1 at 25°C, ·H = 116 ·9 kJ mol-1 and AS. = 86 · 29 JK-1 mol-1. At higher pyridine concentrations evidence for a parallel associative reaction was found, for which the rate constant is (1.3 · 0.2).10-3 M-1S-1 25°C. The results are discussed in reference to available literature data.
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  • 89
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 421-424 
    ISSN: 0009-2940
    Keywords: Macrocycles ; Germanium ; UV/Vis spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Linear and cyclic oligomers of Me2Ge-bridged π-systems have been obtained by the reaction of carbo- and heterocyclic anions and dianions with Me2GeCl2. The spectroscopic properties of the new compounds are compared with analogous carbon- and Me2Si-bridged π-systems.
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  • 90
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 431-431 
    ISSN: 0009-2940
    Keywords: o-Phosphanylphenols ; P,O hybrid ligands ; P asymmetry ; C,O-dilithium reagents ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 91
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    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
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    Keywords: Chemistry ; Inorganic Chemistry
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  • 92
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 453-462 
    ISSN: 0009-2940
    Keywords: Cycloadditions ; Catalysis ; 1-Oxa-1,3-dienes ; Molybdenum ; stereoselectivity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molybdenum-mediated [6 + 2]-cycloaddition reactions of unsaturated ketones to cyclotri- or -tetraenes, e.g. cyclohepta-1,3,5-triene or cyclooctatetraene, proceed under very mild conditions, in high yields and with excellent stereoselectivity starting from the appropriate dicarbonylbis[π4-(1-oxa-1,3-diene)]molybdenum complexes. The stereochemistry of the product arising from the reaction of dicarbonylbis[π4-(5-methylhex-3-en-2-one)]molybdenum with cyclohepta-1,3,5-triene allows one to deduce a stepwise mechanism for this addition. The reactants are fused, as would be expected from an exo-type approach, thus indicating an intermolecular attack of the cycloheptatriene. Tungsten oxadiene complexes are effective in analogous reactions at somewhat reduced reaction rates. Catalytic cycloadditions are observed in several cases when 1-5 mol% of the highly reactive dicarbonylbis[π4-(R-(+)-pinocarvone)]molybdenum is employed as the catalyst. Cycloadducts are formed diastereospecifically in most cases. When cyclooctatrienes are employed as reactants, a sequence of electrocyclization of the triene and subsequent [4 + 2]-cycloadditon occurs with high selectivity and efficiency, leading to a pentacyclic ketone. The product structure reveals an endo-type approach of the polyene in this case.
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  • 93
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1223-1229 
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; O ligands ; Cabalticenium cation ; Sodium coordination ; Ligand profile ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The lithium and sodium compounds A[P(O)R2] (A+ = Li+, Na+; R = OPh, OiPr) have been prepared in situ from Hp(O)R2 and butyllithium or sodium hydride. They react with the cyclopentadienyl complexes [(C5H5)MI2(CO)] (M = Co, Rh), [(C5Me5)CoCl2]2, and [(C5H5)CoI2]n to yield alkali metal salts AL of tridentate oxygen ligands (A+ = Li+, Na+; L- = [(C5R′5]M{P(O)R2}3]-, R′ = H, Me; M = Co, Rh; R = OPh, OiPr) (2). For the ligand LCo, OPh = [(C5H5)-Co{P(O)(OPh)2}3]-, an alternative synthesis has been developed, starting from [(C5H5)2Co]PF6. The structure of the sodium salt NaLCo, OPh (2d) has been determined by X-ray diffraction. The ligand LCo, Oph-, with a cone angle TH of about 200°, completely blocks one half of the coordination sphere around the sodium centre. The ligand profile has been calculated to allow appraisal of the angular encumbrance of the ligand.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1241-1252 
    ISSN: 0009-2940
    Keywords: Organometallic complexes ; Cyanide bridges ; Structure elucidation ; Isomerizations ; Oxidation ; Mixed valent compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 21 new organometallic complexes of the type M-Cn-M′ containing the building blocks M, M′ = (CO)5Cr, (CO)5Mo, (CO)5W, Cp(CO)2Mn, Cp(CO)2Fe, Cp(CO)(CN)Fe, Cp(dppe)Fe, Cp(PPh3)2Ru, Cp(PPh3)Ni, and (PPh3)2Ag were obtained from the reagents M-Cn and M-X (X = leaving group). Among them are five pairs of linkage isomers M-CN-M′/M-NC-M′. Structure determinations of (CO)5Cr-CN-M′ with M′ = Fe(dppe)Cp, Ni(PPh3)Cp, Ag(PPh3)2 and of (CO)5Cr-NC-Fe(dppe)Cp have proved their identity and the linkage isomerism. Systematic variations of the v(CN) and v(CO) IR bands allow as assessment of the relative electron pair acceptor strengths of the building blocks M and M′ and a reliable identification of the individual linkage isomers. All dinuclear complexes are redox-active, showing at lease one reversible oxidation. The redox potentials are characteristically dependent upon the nature of the building blocks M and M′ and upon the orientation of the cyanide link (CN vs. NC), 6 oxidized complexes of the type [M-Cn-Fe(dppe)Cp]+ were prepared chemically and isolated as PF6 or BF4salts. The molecular structure of [(CO)5Cr-CN-Fe(dppe)Cp]BF4 is not significantly different from those of the corresponding neutral Cr-CN-Fe or Cr-NC-Fe complexes. Upon oxidation the v(CN) band of the complexes shifts to lower wavenumbers and becomes much more intense. The oxidized complexes show the paramagnetism due to one unpaired electron. They give rise to very intense metal-to metal charge-transfer bands in the near infrared region whose position was found to be characteristically dependent on solvent polarity of [(CO)5Cr-CN-Fe(dppe)Cp]BF4. A semiquantitative treatment of the optical and electrochemical measurements shows that the electron delocalization and metal-metal interaction in the oxidized dinuclear complexes is significant and that they belong to the class-II mixed-valence systems.
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1273-1277 
    ISSN: 0009-2940
    Keywords: Transition metal ; Complexes of the iron triad ; Density functional calculations ; Relativistic effects ; Hydrido complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures and relative energies of various isomers of [FeH3(PMe3)4)+ (1), [RuH3(PMe3)4]. (2) and [OsH3(PMe3)4]. (3) have been studies by density functional theory. The stereoisomers considered are derived from a tetrahedral (T), square planar (P), and C2v-butterfly (C) arrangement of the phosphane ligands. For the latter two, classical trihydride (I) and nonclassical hydride/dihydrogen (II) geometries have been considered 1 and 2 prefer coordination mode II, whereas 3 favours coordination mode I. This trend is explained by relativistic effects. For Fe and Os, the C and T type structures are preferred over a P geometry. for Ru, the C and P structures are close in energy, and the T arrangement represents the highest energy isomer.
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  • 96
    ISSN: 0009-2940
    Keywords: Carbyne complexes ; Phosphaalkenes ; Molybdenum ; Tungsten ; . interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Condensation of [Tp](CO)2 Mčl] [1: M = Mo; 2: W; Tp] HB (3,5-Me2HC2N2)3] with the inverse phosphaalkenes Me3 Sip=C(NR2)2 (3a: R = Me; 3b: Et) affords the novel phosphaalkenyl carbyne complexes [Tp](CO)2M.C-P=C(NR2)2] (a, b) (M = Mo; R = Me, Et) and 5a, b (M = W; R = Me, Et), which have been characterized by IR, 1H-, 13C- and 31P-NMR spectroscopy. In additon, the molecular structure of 5 has been elucidated by a single-crystal X-ray structure determination.
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  • 97
    ISSN: 0009-2940
    Keywords: Asymmetric catalysis ; Hydroarylation ; Palladium ; P-N ligands ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of optically active biaryl bisphosphanes 10-12, a diphenylphosphanylphenyloxazoline 8, and a (β-N-sulfonyl-aminomethyl)bisdiphenylphosphane 7 as ligands in the Pd-catalyzed Heck-type hydroarylation of norbornene (1) with phenyl 2 and various hetaryl derivaties 3-5 leads exclusively to the formation of exo-2(het)arylnorbornanes 6 with asymmetric inductions of up to 86.4% ee. In addition to an investigation into the effects of different chiral ligands, a systematic study has been made of the influence of various (het)aryl compounds, leaving groups, and solvents on the chemical and optical yields of this reductive arylation.
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  • 98
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    Keywords: Rhenium ; Technetium ; Radiop[pharmaceuticals ; Mixed-ligand complexes ; sulfur ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Neutral oxorhenium(V) complexes with dithioether ligands of the general formula [ReOX3(RS[CH2]2SR)], × = Cl, Br, R = nBu, Et, Bzl were synthesized. Ammonium perrhenate reacts in concentrated hydrochloric acid with dithiaalkanes (RS[CH2]2SR, R =nBu, Et, Bz) dissolved in glacial acetic acid to give octahedral complexes of the type [ReOCl3(RS[CH2]2SR)] (1a-c). In concentrated hydrobromic acid, nBu-S(Ch2)2S-nBu leads to the corresponding tribromo complexes (2). The X-ray structure of shows a distorted octahedron with facial coordination of the bromide ligands. The sulfur atoms are cis coordinated to the terminal oxygen. Dissolution o f1a (R = nBu) in methanol leads to the substitution of the chloride trans to the oxo ligand by a meth oxy group. The resultant complex [ReOCl2(MeO) (nBu-S[CHL2]2S-nBu)] (3) is stable and can be isolated from methanolic solution, but changes to the μ-oxo-bridged dirhenium complex μ-oxobis[dichloro(5,6-dithiadidodecane)oxorhenium(V)] (4) when dissolved in other organic solvents. 1a reacts with an excess of benzenethiol by substitution of two chlorides to give the mixed-ligand complex bis(benzenethiolate)chloro(5,8-dithiadodecane)oxorhenium(V) (5a). The related 4-methylbenzenethiolato complex 5b was synthesized starting from the μ-oxo complex 4. X-ray crystal structure determination of 5b shows the equatorial arrangement of the sulfur atoms. The trans position to the oxygen atom is occupied by a chloride ion.
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  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. i 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 100
    ISSN: 0009-2940
    Keywords: Chiral tripod ligands ; Tripod Mo(CO)3 compounds ; Diastereoselective synthesis ; Separation of diastereomers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Following a procedure developed for H3CC[CH2P(Ph)2]3 (1a) as the starting compound, various tripod ligands RCH2C[CH2P(Ar)2]3 (1) have been transformed into the trilithiotriphosphides RCH2C[CH2P(Ar)(Li)]3 with various electrophiles R′  -  Hal leads to the two diastereomers of RCH2C[CH2P-(Ar)(R)]3 (6) with an (RRR/SSS : RRS/SSR) ratio close to the statistical value of 1:3, except when Ar=Ph and R′=Bzl, where the RRS/SSR diastereomer is obtained almost exclusively. In contrast, the reaction of [RCH2C[CH2P(Ar)(Li)[3]-Mo(CO)3 (4) with electrophiles R′  -  Hal tends to favour the formation of the homochiral RRR/SSS diastereomers. The triphosphide coordination compounds 4 are available by two different routes: either the complexes (RCH2C[CH2P-(Ar)(H)]3Mo(CO)3, obtained from 2 and (CH3CN)3Mo(CO)3, are deprotonated by MeLi, or the trilithiotriphosphides RCH2C[CH2P(Ar)(Li)]3 are reacted with (CH3CN)3Mo(CO)3 to produce 4 in high yields. The ration in which the two diastereomeric forms of 5 are obtained depends on the nature of the electrophile: the greatest diastereomeric discrimination is obtained for Ar=Ph, R=Ph, R′=Bzl, where the homochiral relative to the RRS/SSR pair. Two-dimensional NMR spectra and simulations of one-dimensional spectra are used to ascertain the diastereomeric excess in each case. X-ray analyses of three compounds of type 5 (5d, Ar=Ph, R=H, R′=Ph, R′=Bzl) indicate the remarkable conformational stability of the tripod metal scaffolding, with the conformations observed for these three compounds in three different solid-state environments being closely similar, even with respect to the torsional arrangement of the phosphorus-bound benzyl groups.
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