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  • Inorganic Chemistry  (3,618)
  • FLUID MECHANICS AND HEAT TRANSFER  (3,305)
  • 2015-2019  (5)
  • 1990-1994  (6,918)
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  • 1
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-01-27
    Description: Polynitrogens have the potential for ultrahigh-performing explosives or propellants because singly or doubly bonded polynitrogens can decompose to triply bonded dinitrogen (N2) with an extraordinarily large energy release. The large energy content and relatively low activation energy toward decomposition makes the synthesis of a stable polynitrogen allotrope an extraordinary challenge. Many elements exist in different forms (allotropes)—for example, carbon can exist as graphite, diamond, buckyballs, or graphene. However, no stable neutral allotropes are known for nitrogen, and only two stable homonuclear polynitrogen ions had been isolated until now—namely, the N3− anion (1) and the N5+ cation (2). On page 374 of this issue, Zhang et al. (3) report the synthesis and characterization of the first stable salt of the cyclo-N5− anion, only the third stable homonuclear polynitrogen ion ever isolated. Author: Karl O. Christe
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-01-27
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-02-10
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2016-09-09
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2016-11-11
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2011-08-24
    Description: Numerical results obtained with direct simulation Monte Carlo and Navier-Stokes methods are presented for a Mach-20 nitrogen flow about a 70-deg blunted cone. The flow conditions simulated are those that can be obtained in existing low-density hypersonic wind tunnels. Three sets of flow conditions are considered with freestream Knudsen numbers ranging from 0.03 to 0.001. The focus is on the wake structure: how the wake structure changes as a function of rare faction, what the afterbody levels of heating are, and to what limits the continuum models are realistic as rarefunction in the wake is progressively increased. Calculations are made with and without an afterbody sting. Results for the afterbody sting are emphasized in anticipation of an experimental study for the current flow conditions and model configuration. The Navier-Stokes calculations were made with and without slip boundary conditions. Comparisons of the results obtained with the two simulation methodologies are made for both flowfield structure and surface quantities.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 32; 7; p. 1399-1406
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  • 7
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    In:  Other Sources
    Publication Date: 2011-08-24
    Description: This paper presents the results of a study on the variation of the critical Marangoni number (Ma(sub c)) for the onset of Benard convection in a finite liquid layer bounded horizontally as well as from below. A direct-numerical-simulation procedure is devised to determine the Ma(sub c) for aspect ratios (Ar) ranging from 0.8 to 10. The results predict a strong increase of Ma(sub c) as Ar decreases to below 2. A dip of Ma(sub c) occurs between Ar = 1.45 and 1.3, which is accompanied by a pattern transition from a two-cell convection to a unicellular flow. For Ar above 4, the calculated Ma(sub c) shows little change and asymptotically approach a value of 116.15, with Biot number (Bi) equal to 1.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Microgravity Science and Technology (ISSN 0938-0108); 7; 2; p. 98-109
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  • 8
    Publication Date: 2011-08-24
    Description: The Thermal Radiation Analyzer System, TRASYS, is a computer software system with generalized capability to solve the radiation related aspects of thermal analysis problems. TRASYS computes the total thermal radiation environment for a spacecraft in orbit. The software calculates internode radiation interchange data as well as incident and absorbed heat rate data originating from environmental radiant heat sources. TRASYS provides data of both types in a format directly usable by such thermal analyzer programs as SINDA/FLUINT (available from COSMIC, program number MSC-21528). One primary feature of TRASYS is that it allows users to write their own driver programs to organize and direct the preprocessor and processor library routines in solving specific thermal radiation problems. The preprocessor first reads and converts the user's geometry input data into the form used by the processor library routines. Then, the preprocessor accepts the user's driving logic, written in the TRASYS modified FORTRAN language. In many cases, the user has a choice of routines to solve a given problem. Users may also provide their own routines where desirable. In particular, the user may write output routines to provide for an interface between TRASYS and any thermal analyzer program using the R-C network concept. Input to the TRASYS program consists of Options and Edit data, Model data, and Logic Flow and Operations data. Options and Edit data provide for basic program control and user edit capability. The Model data describe the problem in terms of geometry and other properties. This information includes surface geometry data, documentation data, nodal data, block coordinate system data, form factor data, and flux data. Logic Flow and Operations data house the user's driver logic, including the sequence of subroutine calls and the subroutine library. Output from TRASYS consists of two basic types of data: internode radiation interchange data, and incident and absorbed heat rate data. The flexible structure of TRASYS allows considerable freedom in the definition and choice of solution method for a thermal radiation problem. The program's flexible structure has also allowed TRASYS to retain the same basic input structure as the authors update it in order to keep up with changing requirements. Among its other important features are the following: 1) up to 3200 node problem size capability with shadowing by intervening opaque or semi-transparent surfaces; 2) choice of diffuse, specular, or diffuse/specular radiant interchange solutions; 3) a restart capability that minimizes recomputing; 4) macroinstructions that automatically provide the executive logic for orbit generation that optimizes the use of previously completed computations; 5) a time variable geometry package that provides automatic pointing of the various parts of an articulated spacecraft and an automatic look-back feature that eliminates redundant form factor calculations; 6) capability to specify submodel names to identify sets of surfaces or components as an entity; and 7) subroutines to perform functions which save and recall the internodal and/or space form factors in subsequent steps for nodes with fixed geometry during a variable geometry run. There are two machine versions of TRASYS v27: a DEC VAX version and a Cray UNICOS version. Both versions require installation of the NASADIG library (MSC-21801 for DEC VAX or COS-10049 for CRAY), which is available from COSMIC either separately or bundled with TRASYS. The NASADIG (NASA Device Independent Graphics Library) plot package provides a pictorial representation of input geometry, orbital/orientation parameters, and heating rate output as a function of time. NASADIG supports Tektronix terminals. The CRAY version of TRASYS v27 is written in FORTRAN 77 for batch or interactive execution and has been implemented on CRAY X-MP and CRAY Y-MP series computers running UNICOS. The standard distribution medium for MSC-21959 (CRAY version without NASADIG) is a 1600 BPI 9-track magnetic tape in UNIX tar format. The standard distribution medium for COS-10040 (CRAY version with NASADIG) is a set of two 6250 BPI 9-track magnetic tapes in UNIX tar format. Alternate distribution media and formats are available upon request. The DEC VAX version of TRASYS v27 is written in FORTRAN 77 for batch execution (only the plotting driver program is interactive) and has been implemented on a DEC VAX 8650 computer under VMS. Since the source codes for MSC-21030 and COS-10026 are in VAX/VMS text library files and DEC Command Language files, COSMIC will only provide these programs in the following formats: MSC-21030, TRASYS (DEC VAX version without NASADIG) is available on a 1600 BPI 9-track magnetic tape in VAX BACKUP format (standard distribution medium) or in VAX BACKUP format on a TK50 tape cartridge; COS-10026, TRASYS (DEC VAX version with NASADIG), is available in VAX BACKUP format on a set of three 6250 BPI 9-track magnetic tapes (standard distribution medium) or a set of three TK50 tape cartridges in VAX BACKUP format. TRASYS was last updated in 1993.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: MSC-21030
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  • 9
    Publication Date: 2011-08-24
    Description: This algorithm has been developed for calculating both the quantity of compressor bleed flow required to cool a turbine and the resulting decrease in efficiency due to cooling air injected into the gas stream. Because of the trend toward higher turbine inlet temperatures, it is important to accurately predict the required cooling flow. This program is intended for use with axial flow, air-breathing jet propulsion engines with a variety of airfoil cooling configurations. The algorithm results have compared extremely well with figures given by major engine manufacturers for given bulk metal temperatures and cooling configurations. The program calculates the required cooling flow and corresponding decrease in stage efficiency for each row of airfoils throughout the turbine. These values are combined with the thermodynamic efficiency of the uncooled turbine to predict the total bleed airflow required and the altered turbine efficiency. There are ten airfoil cooling configurations and the algorithm allows a different option for each row of cooled airfoils. Materials technology is incorporated and requires the date of the first year of service for the turbine stator vane and rotor blade. The user must specify pressure, temperatures, and gas flows into the turbine. This program is written in FORTRAN IV for batch execution and has been implemented on an IBM 3080 series computer with a central memory requirement of approximately 61K of 8 bit bytes. This program was developed in 1980.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: LEW-13999
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  • 10
    Publication Date: 2011-08-24
    Description: A fast algorithm has been developed for accurately generating boundary-conforming, three-dimensional consecutively refined computational grids applicable to arbitrary wing-body and axial turbomachinery geometries. This algorithm has been incorporated into the GRID3O computer program. The method employed in GRID3O is based on using an analytic function to generate two-dimensional grids on a number of coaxial axisymmetric surfaces positioned between the centerbody and the outer radial boundary. These grids are of the O-type and are characterized by quasi-orthogonality, geometric periodicity, and an adequate resolution throughout the flow field. Because the built-in nonorthogonal coordinate stretching and shearing cause the grid lines leaving the blade or wing trailing-edge to end at downstream infinity, use of the generated grid simplifies the numerical treatment of three-dimensional trailing vortex sheets. The GRID3O program is written in FORTRAN IV for batch execution and has been implemented on an IBM 370 series computer with a central memory requirement of approximately 450K of 8 bit bytes. The GRID3O program was developed in 1981.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: LEW-13818
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  • 11
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    In:  Other Sources
    Publication Date: 2011-08-24
    Description: The Simplified Shuttle Payload Thermal Analyzer program (SSPTA) was developed to aid in the evaluation of thermal design concepts of instruments to be flown in the Space Shuttle cargo bay. SSPTA consists of a collection of programs that are currently used in the thermal analysis of spacecraft and have been modified for quick, preliminary analysis of payloads. SSPTA includes a reduced math model of the Shuttle cargo bay to simplify use of the program for payload analysis. One of the prime objectives in developing SSPTA was to create a program which was easy to use. With SSPTA, the user required input is simple and the user is free from many of the concerns of computer usage such as disk space handling, tape usage, and complicated program control. Although SSPTA was designed primarily to analyze Shuttle payloads, it can easily be used to perform thermal analysis in other situations. SSPTA is comprised of a system of data files called 'bins', a master program, and a set of thermal subprograms. The bin system is a collection of disk files which contain data required by or computed by the thermal subprograms. SSPTA currently has the capability of handling 50 bins. The master program serves primarily as a manager for the bin system and its interaction with the thermal subprograms. Input to the master program consists of simple user commands which direct the data manipulation procedures, prepare the data for these procedures, and call the appropriate thermal subprograms. The subprograms of SSPTA are all based on programs which have been used extensively in the analysis of orbiting spacecraft and space hardware. Subprogram CONSHAD uses the user supplied geometric radiation model to compute black body view factors, shadow factors, and a description of the surface model. The subprogram WORKSHEET uses the surface model description, optical property data, and node assignment data to prepare input for SCRIPTF. Subprogram SCRIPTF computes the inverses of the infrared (IR) and ultraviolet (UV) radiation transfer equations; it also computes the radiation coupling between nodes in the thermal model. Subprogram ORBITAL uses the shadow tables to compute incident flux intensities on each surface in the geometric model. Subprogram ABSORB uses these flux intensities combined with the IR and UV inverses to compute the IR and UV fluxes absorbed by each surface. The radiation couplings from SCRIPTF and the absorbed fluxes from ABSORB are used by subprogram TTA to compute the temperature and power balance for each node in the thermal model. Output consists of tabulated data from each of the subprograms executed during a particular analysis. Due to the modular form of SSPTA, analyses may be run in whole or in part, and new subprograms may be added by the user. SSPTA is written in FORTRAN for use on a DEC VAX-11/780. SSPTA was originally developed in 1977 for use on IBM 370 series computers. This version is an update which was ported to the VAX in 1980.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: GSC-12698
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  • 12
    Publication Date: 2011-08-24
    Description: The ability to treat arbitrary boundary shapes is one of the most desirable characteristics of a method for generating grids. 3DGRAPE is designed to make computational grids in or about almost any shape. These grids are generated by the solution of Poisson's differential equations in three dimensions. The program automatically finds its own values for inhomogeneous terms which give near-orthogonality and controlled grid cell height at boundaries. Grids generated by 3DGRAPE have been applied to both viscous and inviscid aerodynamic problems, and to problems in other fluid-dynamic areas. 3DGRAPE uses zones to solve the problem of warping one cube into the physical domain in real-world computational fluid dynamics problems. In a zonal approach, a physical domain is divided into regions, each of which maps into its own computational cube. It is believed that even the most complicated physical region can be divided into zones, and since it is possible to warp a cube into each zone, a grid generator which is oriented to zones and allows communication across zonal boundaries (where appropriate) solves the problem of topological complexity. 3DGRAPE expects to read in already-distributed x,y,z coordinates on the bodies of interest, coordinates which will remain fixed during the entire grid-generation process. The 3DGRAPE code makes no attempt to fit given body shapes and redistribute points thereon. Body-fitting is a formidable problem in itself. The user must either be working with some simple analytical body shape, upon which a simple analytical distribution can be easily effected, or must have available some sophisticated stand-alone body-fitting software. 3DGRAPE does not require the user to supply the block-to-block boundaries nor the shapes of the distribution of points. 3DGRAPE will typically supply those block-to-block boundaries simply as surfaces in the elliptic grid. Thus at block-to-block boundaries the following conditions are obtained: (1) grids lines will match up as they approach the block-to-block boundary from either side, (2) grid lines will cross the boundary with no slope discontinuity, (3) the spacing of points along the line piercing the boundary will be continuous, (4) the shape of the boundary will be consistent with the surrounding grid, and (5) the distribution of points on the boundary will be reasonable in view of the surrounding grid. 3DGRAPE offers a powerful building-block approach to complex 3-D grid generation, but is a low-level tool. Users may build each face of each block as they wish, from a wide variety of resources. 3DGRAPE uses point-successive-over-relaxation (point-SOR) to solve the Poisson equations. This method is slow, although it does vectorize nicely. Any number of sophisticated graphics programs may be used on the stored output file of 3DGRAPE though it lacks interactive graphics. Versatility was a prominent consideration in developing the code. The block structure allows a great latitude in the problems it can treat. As the acronym implies, this program should be able to handle just about any physical region into which a computational cube or cubes can be warped. 3DGRAPE was written in FORTRAN 77 and should be machine independent. It was originally developed on a Cray under COS and tested on a MicroVAX 3200 under VMS 5.1.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ARC-12620
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  • 13
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    In:  Other Sources
    Publication Date: 2011-08-24
    Description: This software package includes two programs, the KPD12 and the KPD12P. Both programs utilizes the vortex-blob method to simulate flow around solid bodies, in an unbounded domain using the KPD12, with periodicity in one direction using the KPD12P. The main advantage of the vortex-blob method is the ability to handle situations involving arbitrary shapes including multiple bodies. The user just supplies points on the solid boundaries; there is no grid. The KPD12 program has worked successfully on bluff bodies, stalled wings, and multiple-element airfoils. The KPD12P program has been used successfully on high-solidity separated cascades and on cases of rotating stall in cascades of thin airfoils. However, they do not capture subtle viscous effects such as incipient separation and friction drag. The KPD12 and the KPD12P programs apply the vortex-blob method to time-dependent, high-Reynolds-number flows around solid bodies. Both programs solve the two-dimensional incompressible Navier-Stokes equations, neglecting the viscous effects away from the walls. By creating new vortices along the wall at every time step, they treat the no-penetration and no-slip boundary conditions while using an influence matrix. The code automatically controls the number of vortices. Furthermore, the code has the option of treating the boundary layers by simple integral methods to determine the separation points. The KPD12 outputs forces, moments, and pressure distributions on the bodies. The KPD12P also outputs the turning angle and loss of total pressure. The source code is in Cray FORTRAN and contains a few calls to Cray vector functions which are vectorized with the Cray compiler. However, substitutes for these vector functions are provided. The code is set up to plot the bodies, vortex positions, and streamlines using the DISSPLA graphics software. The software requires a mainframe computer with at least 589k of memory available running under COS 1.16. KPD12 was developed in 1988.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ARC-12119
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  • 14
    Publication Date: 2011-08-24
    Description: INS3D computes steady-state solutions to the incompressible Navier-Stokes equations. The INS3D approach utilizes pseudo-compressibility combined with an approximate factorization scheme. This computational fluid dynamics (CFD) code has been verified on problems such as flow through a channel, flow over a backwardfacing step and flow over a circular cylinder. Three dimensional cases include flow over an ogive cylinder, flow through a rectangular duct, wind tunnel inlet flow, cylinder-wall juncture flow and flow through multiple posts mounted between two plates. INS3D uses a pseudo-compressibility approach in which a time derivative of pressure is added to the continuity equation, which together with the momentum equations form a set of four equations with pressure and velocity as the dependent variables. The equations' coordinates are transformed for general three dimensional applications. The equations are advanced in time by the implicit, non-iterative, approximately-factored, finite-difference scheme of Beam and Warming. The numerical stability of the scheme depends on the use of higher-order smoothing terms to damp out higher-frequency oscillations caused by second-order central differencing. The artificial compressibility introduces pressure (sound) waves of finite speed (whereas the speed of sound would be infinite in an incompressible fluid). As the solution converges, these pressure waves die out, causing the derivation of pressure with respect to time to approach zero. Thus, continuity is satisfied for the incompressible fluid in the steady state. Computational efficiency is achieved using a diagonal algorithm. A block tri-diagonal option is also available. When a steady-state solution is reached, the modified continuity equation will satisfy the divergence-free velocity field condition. INS3D is capable of handling several different types of boundaries encountered in numerical simulations, including solid-surface, inflow and outflow, and far-field boundaries. Three machine versions of INS3D are available. INS3D for the CRAY is written in CRAY FORTRAN for execution on a CRAY X-MP under COS, INS3D for the IBM is written in FORTRAN 77 for execution on an IBM 3090 under the VM or MVS operating system, and INS3D for DEC RISC-based systems is written in RISC FORTRAN for execution on a DEC workstation running RISC ULTRIX 3.1 or later. The CRAY version has a central memory requirement of 730279 words. The central memory requirement for the IBM is 150Mb. The memory requirement for the DEC RISC ULTRIX version is 3Mb of main memory. INS3D was developed in 1987. The port to the IBM was done in 1990. The port to the DECstation 3100 was done in 1991. CRAY is a registered trademark of Cray Research Inc. IBM is a registered trademark of International Business Machines. DEC, DECstation, and ULTRIX are trademarks of the Digital Equipment Corporation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ARC-11794
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  • 15
    Publication Date: 2011-08-24
    Description: The ability to treat arbitrary boundary shapes is one of the most desirable characteristics of a method for generating grids, including those about airfoils. In a grid used for computing aerodynamic flow over an airfoil, or any other body shape, the surface of the body is usually treated as an inner boundary and often cannot be easily represented as an analytic function. The GRAPE computer program was developed to incorporate a method for generating two-dimensional finite-difference grids about airfoils and other shapes by the use of the Poisson differential equation. GRAPE can be used with any boundary shape, even one specified by tabulated points and including a limited number of sharp corners. The GRAPE program has been developed to be numerically stable and computationally fast. GRAPE can provide the aerodynamic analyst with an efficient and consistent means of grid generation. The GRAPE procedure generates a grid between an inner and an outer boundary by utilizing an iterative procedure to solve the Poisson differential equation subject to geometrical restraints. In this method, the inhomogeneous terms of the equation are automatically chosen such that two important effects are imposed on the grid. The first effect is control of the spacing between mesh points along mesh lines intersecting the boundaries. The second effect is control of the angles with which mesh lines intersect the boundaries. Along with the iterative solution to Poisson's equation, a technique of coarse-fine sequencing is employed to accelerate numerical convergence. GRAPE program control cards and input data are entered via the NAMELIST feature. Each variable has a default value such that user supplied data is kept to a minimum. Basic input data consists of the boundary specification, mesh point spacings on the boundaries, and mesh line angles at the boundaries. Output consists of a dataset containing the grid data and, if requested, a plot of the generated mesh. The GRAPE program is written in FORTRAN IV for batch execution and has been implemented on a CDC 6000 series computer with a central memory requirement of approximately 135K (octal) of 60 bit words. For plotted output the commercially available DISSPLA graphics software package is required. The GRAPE program was developed in 1980.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ARC-11379
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  • 16
    Publication Date: 2017-10-02
    Description: The objective of this paper is to review the efforts in spatial direct numerical simulations for transition modeling. Much recent success has been realized in the development of more efficient numerical algorithms as well as a robust downstream boundary condition. Efforts at explaining complex physical phenomena through the use of simulations are reviewed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD, Special Course on Progress in Transition Modelling; 46 p
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  • 17
    Publication Date: 2016-06-07
    Description: Results of atomization tests of rocket injection elements are correlated in terms of the test fluid properties and the injection element operating conditions. The type of element modeled has a central, swirling liquid oxidizer flow; and a coaxial, axial gaseous fuel flow. Results of the correlations describe the effect of geometry, fluid properties, and operating conditions on liquid atomization. The ranges of test conditions allow reasonable extrapolation to actual high-pressure engine operating conditions. At such conditions, the swirl element should produce exceptionally finely-atomized and well-distributed spray for high combustion performance. United Technologies Research Center (UTRC) completed a test program to measure fluid spray atomization, in terms of droplet size and droplet size distributions, for swirling-flow injection elements. Element sizes and dimensions covered ranges of dimensions representative of typical cryogenic (O2/H2) liquid rocket engine practice. Relevant dimensions include the element diameter, the tangential-entry metering slot length, and the coastal fuel slot radial gap. Test fluids included water, simulated Jet-A, and Freon 113. These fluids cover ranges of properties which include or approach those of liquid oxygen. Gaseous nitrogen simulated the coaxial gaseous hydrogen fuel flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Pennsylvania State Univ., NASA Propulsion Engineering Research Center, Volume 2; p 202
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  • 18
    Publication Date: 2016-06-07
    Description: Studies of the interaction of unsteady (oscillatory) flows with the growth of a turbulent boundary layer on a flat plate have primarily dealt with an oscillatory component in the primary flow direction. Past studies of the 2-D flow have shown little or no increase in the time averaged heat transfer. The present paper deals with a steady axial and an oscillatory transverse flow. It is shown that for such flows the temporal variation for both the turbulent skin friction and heat transfer are such as to yield increased time averaged values.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA Propulsion Engineering Research Center, Volume 2; p 189
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  • 19
    Publication Date: 2016-06-07
    Description: NASA/Marshall Space Flight Center (MSFC) has an ongoing effort to transfer to industry the technologies developed at MSFC for rocket propulsion systems. The Technology Utilization (TU) Office at MSFC promotes these efforts and accepts requests for assistance from industry. One such solicitation involves a request from North American Marine Jet, Inc. (NAMJ) for assistance in the design of a water-jet-drive system to fill a gap in NAMJ's product line. NAMJ provided MSFC with a baseline axial flow impeller design as well as the relevant working parameters (rpm, flow rate, etc.). This baseline design was analyzed using CFD, and significant deficiencies identified. Four additional analyses were performed involving MSFC changes to the geometric and operational parameters of the baseline case. Subsequently, the impeller was redesigned by NAMJ and analyzed by MSFC. This new configuration performs significantly better than the baseline design. Similar cooperative activities are planned for the design of the jet-drive inlet.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Pennsylvania State Univ., NASA Propulsion Engineering Research Center, Volume 2; p 69-74
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  • 20
    Publication Date: 2016-06-07
    Description: The objective of this research is to obtain an improved understanding of the behavior of droplets in vaporizing sprays, particularly under conditions typical of those in high pressure rocket sprays. Experiments are conducted in a variety of high pressure, high temperature, optically-accessible flow systems, including one which is capable of operation at pressures up to 70 atm, temperatures up to 600 K, gas velocities up to 30 m/sec and turbulence intensities up to 40 percent. Single droplets, 50 to 500 micron in diameter, are produced by an aerodynamic droplet generator and transversely injected into the flow. Measurements are made of the droplet position, size, velocity and temperature and of the droplet's vapor wake from which droplet drag, dispersion, heating, vaporization and breakup are characterized.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA Propulsion Engineering Research Center, Volume 2; p 203-205
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  • 21
    Publication Date: 2016-06-07
    Description: A systematic investigation has been conducted to study the effects of ambient flow conditions (i.e. pressure and velocity) on supercritical droplet gasification in a forced-convective environment. The model is based on the time-dependent conservation equations in axisymmetric coordinates, and accommodates thermodynamic nonidealities and transport anomalies. In addition, an efficient scheme for evaluating thermophysical properties over the entire range of fluid thermodynamic states is established. The analysis allows a thorough examination of droplet behavior during its entire lifetime, including transient gasification, dynamic deformation, and shattering. A parametric study of droplet vaporization rate in terms of ambient pressure and Reynolds number is also conducted.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA Propulsion Engineering Research Center, Volume 2; p 138-142
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  • 22
    Publication Date: 2016-06-07
    Description: The objective of the study is to assess the capability of two-equation turbulence models for simulating propulsion-related flowfields. The standard kappa-epsilon model with Chien's low Reynolds number formulation for near-wall effects is used as the baseline turbulence model. Several experimental test cases, representative of rocket combustor internal flowfields, are used to catalog the performance of the baseline model. Specific flowfields considered here include recirculating flow behind a backstep, mixing between coaxial jets and planar shear layers. Since turbulence solutions are notoriously dependent on grid and numerical methodology, the effects of grid refinement and artificial dissipation on numerical accuracy are studied. In the latter instance, computational results obtained with several central-differenced and upwind-based formulations are compared. Based on these results, improved turbulence modes such as enhanced kappa-epsilon models as well as other two-equation formulations (e.g., kappa-omega) are being studied. In addition, validation of swirling and reacting flowfields are also currently underway.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA Propulsion Engineering Research Center, Volume 2; p 190-194
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  • 23
    Publication Date: 2016-06-07
    Description: Our Sensitivity-Based Minimal Residual (SBMR) method which is based on our earlier Distributed Minimal Residual (DMR) method allows each component of the solution vector in a system of equations to have its own convergence speed. Our global SBMR method was found to consistently outperform the DMR method while requiring considerably less computer memory. Recently, we have developed and tested a new Line SBMR or LSBMR method and a Time-Step-Scaling (TSS) method that are even more robust and computationally efficient than our global SBMR method, especially on highly clustered computational grids in laminar and turbulent flow computations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA Propulsion Engineering Research Center, Volume 2; p 177-181
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  • 24
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 160-166 
    ISSN: 0044-2313
    Keywords: Tetraphosphorus tetraselenide, P4Se4 ; Tetraphosphorus triselenide, P4Se3 ; thermochemistry ; preparation ; structure, 31P-n.m.r. ; glass ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Results on P4Se4Preparation of P4Se4 from the elements yields always the β-modification of P4Se4. α-P4Se4 is obtained only with selenium deficient samples. However, it is also observed, when P4Se3 is annealed and then extracted with CS2. The insoluble part has the X-ray pattern of α-P4Se4. A reversible α-β transition is not observed. MAS-31P-NMR investigations on solid P4Se4 by Eckert et al. [2] reveal P2Se4/2 building units, which are, in view of our results, not dimer but linked to a polymeric network. Well-crystallized samples of β-P4Se4 are obtained only at measuring temperatures above 573 K. The structure is of monoclinic symmetry with the space group P21/n (a = 114.9, b = 729.0, c = 1211.0 pm, β = 120.80°).The reaction of α-P4Se3I2 with bis-(trimethyltin)selenide in CS2 at low temperature yields molecular α-P4Se4, which can be detected in solution by 31P-NMR spectroscopy. α-P4Se4 has D2d-symmetry like α-P4S4. It polymerizes at higher temperature. α-P4Se3I(SeSnMe3) and α-P4Se3(SeSnMe3)2 were observed in the course of this reaction, too. The analogous reaction of α-P4Se3I2 with bis-(trimethyltin)sulfide leads to comparable results.
    Notes: Bei der Synthese von P4Se4 aus den Elementen erhält man stets die aus der Literatur als β-P4Se4 bekannte Modifikation, nur mit einem Selenunterschuß wird α-P4Se4 erhalten, dessen Röntgenbeugungsmuster auch in getemperten P4Se3-Proben gefunden wird, nachdem man die löslichen Anteile extrahiert hat. Eine reversible-α-β-Umwandlung wird nicht beobachtet. MAS-31P-NMR-Messungen von Eckert et al. [2] zeigen, daß β-P4Se4 aus P2Se4/2-Einheiten aufgebaut ist, die nach unseren Untersuchungen allerdings nicht zu Dimeren verknüpft, sondern polymer vernetzt sind. β-P4Se4 kristallisiert störungsfrei nur oberhalb von 573 K mit monokliner symmetrie in der Raumgruppe P21/n (a = 1141,9 pm, b = 729,0 pm, c = 1211,0 pm, β = 120,80°).Die Reaktion von α-P4Se3I2 mit Bis-trimethylzinnselenid in CS2 bei tiefer Temperatur führt erstmals zum NMR-spektroskopischen Nachweis des molekularen α-P4Se4, das eine mit dem α-P4S4 vergleichbare D2d-Symmetrie besitzt und bei Temperaturerhöhung polymerisiert. Die bei der Reaktion eben-falls entstehenden Verbindungen α-P4Se3I(SeSnMe3) und α-P4Se3(SeSnMe3)2 können anhand der 31P-NMR-Daten nachgewiesen werden. Die analoge Reaktion von α-P4Se3I2 mit Bistrimethylzinnsulfid führt zu vergleichbaren Resultaten.
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  • 25
    ISSN: 0044-2313
    Keywords: Trigold manganese cluster ; (Ph3PAu)3Mn(CO)4 ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of (Ph3PAu)3Mn(CO)4Photolysis of (Ph3PAu)Mn(CO)5, Ph3PAuN3 and Ph3PAuNCO yields (Ph3PAu)3Mn(CO)4 (1). 1 crystallizes in the monoclinic space group P21/n with a = 1 031.3(1); b = 3 095.2(3), c = 3 386.3(3) pm; β = 97.58(3)°; Z = 8. The crystal structure contains two symmetry independent clusters 1 of the same geometry. Their inner core MnAu3 forms a rhombus with distances Mn—Au of about the same lengths between 258.4(4) and 262.0(4) pm. The distances Au—Au range from 276.6(2) to 281.3(2) pm. The bonding in 1 is discussed and compared with those of (Ph3PAu)3Co(CO)3 having the same total number of electrons but a tetrahedral framework.
    Notes: Photolyse einer Mischung von (Ph3PAu)Mn(CO)5, Ph3PAuN3 und Ph3PAuNCO in THF führt zur Bildung von (Ph3PAu)3Mn(CO)4 (1). 1 kristallisiert in der monoklinen Raumgruppe P21/n mit a = 1 031,3(1); b = 3 095,2(3), c = 3 386,3(3) pm; β = 97,58(3)°; Z = 8. Die Kristallstruktur enthält zwei symmetrieunabhängige Cluster 1 gleicher Gestalt, deren MnAu3-Gerüst die Struktur einer Raute mit nahezu gleich langen Mn—Au-Abständen zwischen 258,4(4) und 262,0(4) pm aufweist. Die Au—Au-Abstände liegen zwischen 276,6(2) und 281,3(2) pm. Die Bindungsverhältnisse in 1 werden diskutiert und mit denjenigen des Clusters (Ph3PAu)3Co(CO)3 mit gleicher Gesamtelektronenanzahl aber tetraedrischer Gerüststruktur verglichen.
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  • 26
    ISSN: 0044-2313
    Keywords: Silicate hydrate ; 1,1,4,4-tetramethylpiperazinium ; 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane ; 1,1-dimethylpiperidinium ; clathrate ; crystal structure ; double four-ring silicate anion ; hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [TMPA]4[Si8O20] · 34 H2O und [DDBO]4[Si8O20] · 32 H2O sind Heteronetzwerk-Clathrate mit 1,1,4,4-Tetramethylpiperazinium (TMPA) und 1,4-Dimethyl-1,4-Diazoniabicyclo[2.2.2]octan (DDBO) Gastkationen[TMPA]4[Si8O20] · 34 H2O (1) und [DDBO]4[Si8O20] · 32 H2O (2) wurden durch Kristallisation aus wäßrigen Lösungen der entsprechenden quartären Alkylammoniumhydroxide und SiO2 erhalten. Die Kristallstrukturen wurden mittels Einkristallröntgenbeugung bestimmt. 1: Monoklin, a = 16,056(2), b = 22,086(6), c = 22,701(2) Å, β = 90,57(1)° (T = 210 K), Raumgruppe C2/c, Z = 4. 2: Monoklin, a = 14,828(9), b = 20,201(7), c = 15,519(5) Å, β = 124,13(4)° (T = 255 K), Raumgruppe P21/c, Z = 2. Die Polyhydrate sind strukturverwandte Wirt-Gast-Verbindungen mit dreidimensionalen Wirtstrukturen aus über Wasserstoffbrücken verknüpften oligomeren Anionen [Si8O20]8- und H2O-Molekülen. Die Silicat-Anionen haben eine würfelförmige Doppelvierring-Struktur und eine lokale Umgebung, die von 24 H2O-Molekülen und sechs Kationen (TMPA, [C8H20N2]2+, oder DDBO, [C8H18N2]2+) gebildet wird. Die Kationen befinden sich als Gastspezies in großen, unregelmäßigen, käfigartigen Hohlräumen. Untersuchungen mittels der 29Si-NMR-Spektroskopie und der Trimethylsilylierungsmethode haben gezeigt, daß die gesättigten Lösungen von 1 und 2 hohe Anteile an Doppelvierring-Anionen enthalten. Derartige Anionen sind auch in der gesättigten Lösung des Heteronetzwerk-Clathrats [DMPI]6[Si8O18(OH)2] · 48,5 H2O (3) mit 1,1-Dimethylpiperidinium-Kationen (DMPI, [C7H16N]+) als Gastspezies enthalten.
    Notes: [TMPA]4[Si8O20] · 34 H2O (1) and [DDBO]4[Si8O20] · 32 H2O (2) have been prepared by crystallization from aqueous solutions of the respective quaternary alkylammonium hydroxide and SiO2. The crystal structures have been determined by single-crystal X-ray diffraction. 1: Monoclinic, a = 16.056(2), b = 22.086(6), c = 22.701(2) Å, β = 90.57(1)° (T = 210 K), space group C2/c, Z = 4. 2: Monoclinic, a = 14.828(9), b = 20.201(7), c = 15.519(5) Å, β = 124.13(4)° (T = 255 K), space group P21/c, Z = 2. The polyhydrates are structurally related host-guest compounds with three-dimensional host frameworks composed of oligomeric [Si8O20]8- anions and H2O molecules which are linked via hydrogen bonds. The silicate anions possess a cube-shaped double four-ring structure and a characteristic local environment formed by 24 H2O molecules and six cations (TMPA, [C8H20N2]2+, or DDBO, [C8H18N2]2+). The cations themselves reside as guest species in large, irregular, cage-like voids. Studies employing 29Si NMR spectroscopy and the trimethylsilylation method have revealed that the saturated aqueous solutions of 1 and 2 contain high proportions of double four-ring silicate anions. Such anions are also abundant species in the saturated solution of the heteronetwork clathrate [DMPI]6[Si8O18(OH)2] · 48.5 H2O (3) with 1,1-dimethylpiperidinium (DMPI, [C7H16N]+) guest cations.
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  • 27
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 781-785 
    ISSN: 0044-2313
    Keywords: Oxothallate(III) ; Preparation ; Structure ; MAPLE ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidation of Intermetallic Phases: K4{Na2[Tl2O6]} from NaTl and K2O2The hitherto unknown K4{Na2[Tl2O6]} was prepared in form of transparent, yellow single crystals from NaTl and KO1,08 (molar ratio 1:1.3; sealed Ag-cylinder; 450°C, 30 d). The structure determination (four-circle diffractometer, MoKα, 1 280 out of 1 523 Io(hkl), R = 5.75%, Rw = 4.58%) confirms the space group P21/c with a = 641.3 pm, b = 691.1 pm, c = 1188.5 pm, β = 95.69° and Z = 2. As characteristic building units of the structure there are doubles of tetrahedra of [Tl2O6] and [Na2O6]. The compound is isotypic with Cs6[In2O6] and Rb6[Tl2O6]. The Madelung Part of Lattice Energy, MAPLE, the Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN, and Charge Distribution, CHARDI, are calculated.
    Notes: Bisher unbekanntes K4{Na2[Tl2O6]} wurde durch Oxydation von NaTl mit KO1,08 (1:1,3; geschlossener Ag-Zylinder; 450°C; 30 Tage) in Form transparenter, gelber Einkristalle dargestellt. Die Strukturaufklärung (Vierkreisdiffraktometerdaten, MoKα, 1 280 von 1 523 Io(hkl), R = 5,75%, Rw = 4,58%) erfolgte in der Raumgruppe P21/c mit a = 641,3 pm, b = 691,1 pm, c = 1 188,5 pm, β = 95,69° und Z = 2. Charakteristisches Motiv sind über Kanten verknüpfte, von ihresgleichen „isolierte“ Tetraederdoppel [Tl2O6] und [Na2O6]. Die Verbindung ist isotyp zu Cs6[In2O6] und Rb6[Tl2O6]. Der Madelunganteil der Gitterenergie, MAPLE, die Mittleren fiktiven Ionenradien, MEFIR, Effektive Koordinationszahlen, ECoN, sowie die Ladungsverteilung, CHARDI, werden berechnet.
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  • 28
    ISSN: 0044-2313
    Keywords: Dilithium magnesium tetrachloride ; dilithium vanadium tetrachloride ; dilithium cadmium tetrachloride ; crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structures of MgCrO4-type Li2VCl4 and Spinel-type Li2MgCl4 and Li2CdCl4The crystal structures of the ternary lithium chlorides Li2MCl4 (M = Mg, V, Cd) have been determined firstly by X-ray single-crystal experiments. Li2MgCl4 and Li2CdCl4 crystallize in an inverse spinel structure (space group Fd3m, Z = 8, a = 1 040.1(2) and 1 062.06(9) pm, structural parameters u = 0.25699(2) and 0.2550(1), R = 1.7 and 3.7% for 218 and 211 unique reflections). The Li—Cl distances of the tetrahedrally coordinated Li+ ions are significantly greater than calculated with Shannon's crystal radii ( 〉 238 ± 1 instead of 233 pm). Contrary to the results of X-ray powder data reported in the literature, Li2VCl4 crystallizes in the distorted spinel structure of MgCr2O4 type (space group F43m, Z = 8, a = 1 037.49(2) pm, R = 5.9% for 217 unique reflections). The decrease of the site symmetry of the octahedrally coordinated ions (V2+, Li+) from 3m to 3m resulting in contracted and widened tetrahedral M4 entities of the spinel structure is obviously caused by V—V metal - metal bonds (shortest V—V distance 366.2(7) pm).
    Notes: Die Kristallstrukturen der ternären Lithiumchloride Li2MCl4 (M = Mg, V, Cd) wurden mittels Röntgen-Einkristallmessungen bestimmt. Li2MgCl4 und Li2CdCl4 kristallisieren in einer inversen Spinell-Struktur (Raumgruppe Fd3m, Z = 8, a = 1 040,1(2) und 1 062,06(9) pm, Lageparameter u = 0,25699(2) bzw. 0,2550(1), R = 1,7 bzw. 3,7% bei 218 bzw. 211 symmetrieunabhängigen Reflexen). Die Li—Cl-Abstände der tetraedrisch koordinierten Li+-Ionen sind signifikant größer als erwartet ( 〉 238 ± 1 anstatt 233 pm). Li2VCl4 kristallisiert entgegen Literaturangaben in der verzerrten Spinell-Struktur des MgCrO4-Typs (Raumgruppe F43m, Z = 8, a = 1 037,49(2) pm, R = 5,9% bei 217 symmetrieunabhängigen Reflexen). Die Erniedrigung der Lage-Symmetrie der oktaedrisch koordinierten Ionen (V2+, Li+) von 3m nach 3m, die alternierend zu einer Kontraktion und einer Aufweitung der tetraedrischen M4-Baueinheiten der Spinell-Struktur führt, wird von V—V—Metall - Metall-Bindungen verursacht (kürzester V—V-Abstand 366,2(7) pm).
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  • 29
    ISSN: 0044-2313
    Keywords: Cobalt(III) complexes functionalized N2S2-macrocyclic ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Cobalt(III) Complexes of 14-Membered cis- and trans-N2S2 Dibenzo Macrocycles with two Pendant Acetato GroupsThe isomeric fourteen membered macrocyclic ligands 6,7,9,15,16,18-hexahydrodibenzo[f,m][1,8]dithia[4,11]diazacyclotetradecine-8,17-diacetic acid-0.5-hydrate (H2L3), C22H26N2O4S2 · 0.5 H2O and 6,7,13,15,16,18-hexahydrodibenzo-[e,m][1,4]dithia[8,11]diazacyclotetradecine-14,17-diacetic acid-1.5-hydrate (H2L6), C22H26N2O4S2 · 1.5 H2O with cis- and trans-N2S2 donorsets and two pendant acetato groups form the stable complexes [Co(L3)]ClO4 · 2 H2O (1) and [Co(L6)]ClO4 · H2O (2). Co(III) is octahedrally coordinated herein to all six donor centers of the respective ligand. The macrocyclic rings are folded. The metal ions are located outside the macrocyclic cavity. The mean Co—N, Co—O and Co—S distances are 196, 190 and 224 pm, respectively.Crystal data: 1, monoclinic, space group C2/c, a = 3 797.7(9), b = 763.8(3), c = 2 207.0(7) pm, β = 123.17(2), Z = 8, 3 445 reflections, R(Rw) = 0.072(0.070); 2, monoclinic, space group C2/c, a = 3 197.1(6), b = 880.4(2), c = 1 890.6(4) pm, β = 112,19(3)°, Z = 8, 4 415 reflections, R(Rw) = 0.062(0.064).
    Notes: Die beiden isomeren Liganden 6,7,9,15,16,18-Hexahydrodibenzo[f,m][1,8]dithia[4,11]diazacyclotetradecin-8,17-diessigsäure-0,5-hydrat (H2L3), C22H26N2O4S2 · 0,5 H2O bzw. 6,7,13,15,16,18-Hexahydrodibenzo[e,m][1,4]dithia-[8,11]diazacyclotetradecin-14,17-diessigsäure-1,5-hydrat (H2L6), C22H26N2O4S2 · 1,5 H2O mit cis- bzw. trans-N2S2-Donorzentren im vierzehngliedrigen makrocyclischen Ring und zwei Acetat-Seitenketten bilden die stabilen Komplexe [Co(L3)]ClO4 · 2H2O (1) und [Co(L6)]ClO4 · H2O (2). CoIII ist jeweils von allen 6 Donorzentren der Liganden oktaedrisch umgeben. Die Liganden sind gefaltet. Die Metallatome liegen außerhalb der makrocyclischen Kavität.Kristalldaten: 1, monoklin, Raumgruppe C2/c, a = 3 797,7(9), b = 763,8(3), c = 2 207,0(7) pm, β = 123,17(2)°, Z = 8, 3 445 Reflexe, R(Rw) = 0,072(0,070); 2, monoklin, Raumgruppe C2/c, a = 3 197,1(6), b = 880,4(2), c = 1 890,6(4) pm, β = 112,19(3)°, Z = 8, 4415 Reflexe, R(Rw) = 0,062(0,064).
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  • 30
    ISSN: 0044-2313
    Keywords: Cesium disodium trihydroxide hexahydrate ; deuterated material ; neutron diffraction ; hydrogen bonding ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrates of Weak and Strong Bases. IX. Hydrogen Bonding in CsNa2(OD)3 · 6D2O: A Single-Crystal Neutron-Diffraction Study at 120 KThe title compound is the first hydrate of a ternary alkali hydroxide reported. Its structure is related to the hexagonal perovskites and at the same time shaped by a complex system of hydrogen bonds. In a previous X-ray structure analysis at room temperature of the isotypic undeuterated material, these had been characterized only insufficiently. Therefore a complete structure determination has now been performed on a perdeuterated single crystal using low-temperature neutron-diffraction data (Pca21, Z = 4; a = 13.86, b = 6.070, c = 12.41 Å at 120 K; 1 655 observed independent reflections, R = 0.027).
    Notes: Die Titelverbindung ist das erste beschriebene Hydrat eines ternären Alkalihydroxids. Ihre Struktur ist verwandt mit der der hexagonalen Perowskite und zugleich durch ein komplexes System von Wasserstoffbrücken geprägt. Dieses war in einer vorangegangenen Röntgenstrukturanalyse bei Raumtemperatur an der isotypen nicht deuterierten Substanz nur unzureichend charakterisiert worden. Daher wurde nun eine vollständige Strukturbestimmung an einem perdeuterierten Einkristall mit Tieftemperatur-Neutronenbeugungsdaten durchgeführt (Pca21, Z = 4; a = 13,86, b = 6,070, c = 12,41 Å bei 120 K; 1 655 beobachtete unabhängige Reflexe, R = 0,027).
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  • 31
    ISSN: 0044-2313
    Keywords: Lithiumtetrahydrogenorthoperiodate monohydrate ; crystal structure ; tetrahydrogenorthoperiodate Ion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Existence of the Tetrahydrogenorthoperiodate Ion. The Crystal Structure of LiH4IO6 · H2OThe crystal structure of LiH4IO6 · H2O has been determined (P1; a = 564.74(12), b = 574.41(13), c = 970.4(6) pm, α = 101.37(2), β = 96.37(2), γ = 114.72(2)°; Z = 2; 5 731 independent reflections; R = 0.038). All hydrogen-atoms were localized from difference fourier map and refined without applying constraints. Thus the existence of the tetrahydrogenorthoperiodate-ion in the solid state is proved, unambigously. The crystal structure is discussed and compared to other alkaliorthoperiodates.
    Notes: Die Kristallstruktur von LiH4IO6 · H2O wurde bestimmt (P1; a = 564,74(12), b = 574,41(13), c = 970,4(6) pm, α = 101,37(2), β = 96,37(2), γ = 114,72(2)°; Z = 2; 5 731 unabhängige Reflexe, R = 0,038). Alle Wasserstofflagen konnten aufgefunden und frei verfeinert werden und beweisen erstmals die Existenz des Tetrahydrogenorthoperiodations im Festkörper. Die Kristallstruktur wird diskutiert und mit denjenigen anderer Alkaliorthoperiodate verglichen.
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  • 32
    ISSN: 0044-2313
    Keywords: Sodium Tetrachlorotitanate(II) ; Synthesis ; Crystal Structure ; Magnetism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Crystal Structure and Magnetism of Sodium Tetrachlorotitanate(II), Na2TiCl4Na2TiCl4 is obtained as single crystals by metallothermic reduction of TiCl3 with sodium (525°C, 90 d, Ta container). Pure powder samples may be prepared by synproportionation of TiCl3 with Ti in the presence of NaCl (950-520°C, 21 d). The structure refinement from four-circle diffractometer data confirms that Na2TiCl4 is isotypic with Sr2PbO4 (orthorhombic, space group Pbam (No. 55), Z = 2 a = 694.2(1), b = 1 198.9(2), c = 385.6(1) pm, R = 0.055, Rw = 0,038). Ti2+ is surrounded by a distorted octahedron of Cl-. The octahedra are connected via common edges to chains, ∞1[TiCl2/1Cl4/2]2-, that run in the [001] direction. Magnetic susceptibility data were recorded in the 2 to 300 K temperature range at various field strengths. The interpretation of the data was carried out with the aid of crystal-field calculations taking magnetic interactions into account. The non-Curie behaviour of the reciprocal magnetic susceptibility of Ti2+ in Na2TiCl4 is due to the influence of spin-obit coupling.
    Notes: Na2TiCl4 entsteht in Form von Einkristallen bei der metallothermischen Reduktion von TiCl3 mit Na (525°C, 90 d, Ta-Ampulle). Reine Pulverproben von türkis-grünem Na2TiCl4 sind durch Synproportionierung von TiCl3 mit Titan in Gegenwart von NaCl zugänglich (950-520°C, 21 d). Die Strukturverfeinerung aus Vierkreis-Diffraktometer-Daten bestätigt, daß Na2TiCl4 im Sr2PbO4-Typ kristallisiert (orthorhombisch, Raumgruppe Pbam (Nr. 55), Z = 2, a = 694,2(1), b = 1 198,9(2), c = 385,6(1) pm, R = 0,055, Rw = 0,038). Ti2+ ist in Form eines verzerrten Oktaeders von Cl- umgeben. Die Oktaeder sind über gemeinsame Kanten zu Ketten ∞1[TiCl2/1Cl4/2]2- verknüpft, die längs [001] angeordnet sind. Die magnetische Suszeptibilität wurde im Bereich von 2-300 K bei verschiedenen Feldstärken bestimmt. Die Interpretation der Meßdaten erfolgte über Kristallfeld-Rechnungen unter Berücksichtigung magnetischer Wechselwirkungen. Das Nicht-Curie-Verhalten der reziproken magnetischen Suszeptibilität von Ti2+ in Na2TiCl4 ist auf den Einfluß der Spin-Bahn-Kopplung zurückzuführen.
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  • 33
    ISSN: 0044-2313
    Keywords: GdIII and SmIII octahedra complexes ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Complexes of the Lanthanoides with Bidentate Ligands. The Crystal Structures of [(C17H17N2)GdBr2(thf)2] and [(C17H17N2)3Ln] (L = Sm, Gd)Reaction of [(AIP)Li] with GdBr3 leads to a new mononuclear complex [(AIP)GdBr2(thf)2] 1. In contrast to this with SmI2 the compound [(AIP)3Sm] 2 is build up. Such complexes are also formed with Gd(OR*)3 (R* = OtBu2C6H3) and [(AIP)Li] in a 1:3 ratio, [(AIP)3Gd] 3. The structures of 1-3 were characterized by X-ray single crystal structure analysis (1: space group Pna21 (No. 33), Z = 4, a = 1 972.7(9) pm, b = 984.7(5) pm, c = 1 425.0(8) pm, α = β = γ = 90°; 2 · 2 THF: space group C2/c (No. 15), Z = 8, a = 3 644.4(9) pm, b = 1 437.5(5) pm, c = 2 334.4(7) pm, β = 1 21.07(6)°; 3: space group P2(1)/c (No. 14), Z = 4, a = 1 872.9(1) pm, b = 1 064.6(1) pm, c = 2 282.4(2) pm, β = 103.75(8)°).
    Notes: GdBr3 reagiert mit [(AIP)Li] zu dem einkernigen Komplex [(AIP)GdBr2(thf)2] 1. Mit SmI2 bildet sich dagegen überraschenderweise die Komplexverbindung [(AIP)3Sm] 2. Komplexe dieser Art bilden sich auch bei der Umsetzung von Gd(OR*)3 (R* = OtBu2C6H3) mit [(AIP)Li] im Verhältnis 1:3, [(AIP)3Gd] 3. Der Aufbau von 1-3 konnte durch Kristallstrukturanalyse geklärt werden (1: Raumgruppe Pna21 (Nr. 33), Z = 4, a = 1 972,7(9) pm, b = 984,7(5) pm, c = 1 425,0(8) pm, α = β = γ = 90°; 2 · 2 THF: Raumgruppe C2/c (Nr. 15), Z = 8, a = 3 644,4(9) pm, b = 1 437,5(5) pm, c = 2 334,4(7) pm, β = 1 21,07(6)°; 3: Raumgruppe P2(1)/c (Nr. 14), Z = 4, a = 1 872,9(1) pm, b = 1 064,6(1) pm, c = 2 282,4(2) pm, β = 103,75(8)°).
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  • 34
    ISSN: 0044-2313
    Keywords: MoIV ; GdIII ; Mo—Gd heterobimetallic complex ; X-ray structure analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and structure of a Molybdenum-Gadolinium Heterometallic Complex. The Structure of [Li(thf)4]2[Cp2MoSGdBr4(thf)]2[Cp2MoHLi] reacts in THF with S and GdBr3 to yield the tetranuclear heterobimetallic complex [Li(thf)4]2[Cp2MoSGdBr4(thf)]2. The bonding situation and the structure of this compound were characterized by X-ray structure analysis (space group P1 (No. 2), Z = 1, a = 10.845(2) Å, b = 12.166(2) Å, c = 15.881(2) Å, α = 101.74(2)°, β = 97.62(2)°, γ = 103.97(2)°). Each S atom of the central Mo2S2-ring is coordinated by a GdBr4(thf) fragment. Additionally each Mo atom is connected to two Cp ligands. This leads to a tetrahedral coordination of the Mo atoms and a octahedral coordination of the Gd ions.
    Notes: [Cp2MoHLi] reagiert in THF mit S und GdBr3 zu dem vierkernigen Heterometallkomplex [Li(thf)4]2[Cp2MoSGdBr4(thf)]2. Die Bindungsverhältnisse und der Aufbau dieser Verbindung konnten durch eine Kristallstrukturanalyse geklärt werden (Raumgruppe P1 (Nr. 2), Z = 1, a = 10,845(2) Å, b = 12,166(2) Å, c = 15,881(2) Å, α = 101,74(2), β = 97,62(2)°, γ = 103,97(2)°). An den zentralen Mo2S2-Vierring koordiniert ein GdBr4(thf)-Fragment, so daß jedes Gd-Ion an sechs Liganden gebunden ist. Zusätzlich ist jedes Mo-Atom von zwei Cp-Liganden umgeben und erhält dadurch die Koordinationszahl 4.
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  • 35
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 833-838 
    ISSN: 0044-2313
    Keywords: Fluoromanganate(III) hydrates, Mn3F8 · 12H2O, AgMnF4 · 4 H2O ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Neue Fluoromanganat(III)-Hydrate: Mn3F8 · 12H2O and AgMnF4 · 4H2ODie Fluoridhydrate Mn3F8 · 12H2O und AgMnF4 · 4 H2O wurden in Form von Einkristallen hergestellt und durch Röntgenbeugungsmethoden charakterisiert. Mn3F8 · 12H2O kristallisiert in Raumgruppe P1 (a = 623.0(3), b = 896.7(4), c = 931.8(4) pm, α = 110.07(2)°, β = 103.18(2)°, γ = 107.54(2)°, Z = 1); AgMnF4 · 4 H2O kristallisiert in Raumgruppe P21/m (a = 700.9(2), b = 726.1(1), c = 749.4(3) pm, β = 107.17(3)°, Z = 2). Beide Strukturen enthalten Jahn-Teller-verzerrte [Mn(H2O)2F4]-Anionen und zeigen ein komplexes Wasserstoffbrücken-Netzwerk zwischen Anionen und Kationen, nämlich [Mn(H2O)6]2+ in der ersteren und einem polymeren [Ag(H2O)2]--Kation in der zweiten Verbindung.
    Notes: Single crystals of fluoride hydrates Mn3F8 · 12 H2O and AgMnF4 · 4 H2O have been prepared and characterized by X-ray methods. Mn3F8 · 12 H2O crystallizes in the space group P1 (a = 623.0(3), b = 896.7(4), c = 931.8(4) pm, α = 110.07(2)°, β = 103.18(2)°, γ = 107.54(2)°, Z = 1); AgMnF4 · 4 H2O crystallizes in the space group P21/m (a = 700.9(2), b = 726.1(1), c = 749.4(3) pm, β = 107.17(3)°, Z = 2). Both structures contain Jahn-Teller-distorted [Mn(H2O)2F4]- anions as well as crystal water molecules and exhibit a complex hydrogen bond network between anions and cations, i. e. [Mn(H2O)6]2+ for the first and a polymeric [Ag(H2O)2]- cation for the second compound.
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  • 36
    ISSN: 0044-2313
    Keywords: Single crystal structure ; Fluorzirkonates ; Fluorstannates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Structure of SmZrF7 with an Appendix on EuSnF7 and YSnF7SmZrF7 again was obtained as colourless single crystals and investigated by X-ray methods: It crystallizes in space group P 21/c-C2h5 (Nr. 14; P 21/n) with a = 1 140.9(2) pm, b = 574.6(1) pm, c = 914,4(2) pm, β = 107.32(2)°, Z = 4 but not in space group P 21-C22 (Nr. 4) [1]. In addition EuSnF7 and YSnF7 are isotypic with the following lattice constants: EuSnF7: a = 1 121.8(2) pm, b = 563.7(1) pm, c = 901.7(1) pm, β = 107.35(2)° with Z = 4; YSnF7: a = 1 106.7(2) pm, b = 556.4(1) pm, c = 884.7(1) pm, β = 107.51(1)° and Z = 4 (Powder data).
    Notes: SmZrF7 wurde erneut in Form farbloser Einkristalle dargestellt und röntgenographisch untersucht: Danach kristallisiert es in der Raumgruppe P 21/c-C2h5 (Nr. 14; Aufstellung P 21/n) mit a = 1 140,9(2) pm, b = 574,6(1) pm, c = 914,4(2) pm, β = 107,32(2)°, Z = 4, also nicht in der Raumgruppe P 21-C22 (Nr. 4) [1]. Aufgrund neuer Strukturrechnungen kristallisieren EuSnF7 und YSnF7 ebenfalls in der zentrosymmetrischen Raumgruppe P 21/c-C2h5 (Nr. 14) mit folgenden Gitterkonstanten für EuSnF7: a = 1 121,8(2) pm, b = 563,7(1) pm, c = 901,7(1) pm, β = 107,35(2)° mit Z = 4 sowie für YSnF7 a = 1 106,7(2) pm, b = 556,4(1) pm, c = 884,7(1) pm, β = 107,51(1)° und Z = 4 (Pulverdaten).
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  • 37
    ISSN: 0044-2313
    Keywords: Bis(fluorosulfonyl)difluoromethane ; gas-phase structure ; conformation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Gasphasen-Struktur von Bis(fluorosulfonyl)difluormethan, (SO2F)2CF2Es wird über neue Syntheseverfahren und das Infrarotspektrum von Bis(fluorsulfonyl) Difluormethan, (SO2F)2CF2 berichtet. Die geometrische Struktur und die Konformationseigenschaften dieser Verbindung wurden mittels der Elektronenbeugung an Gasen untersucht. Je nach Stellung der zwei SO2F Gruppen können vier Konformere mit unterschiedlichen Symmetrien auftreten: C2v Symmetrie, falls beide S—F Bindungen auf Lücke zu CF2 stehen, C2 oder Cs Symmetrie, falls eine S=O Bindung jeder SO2F Gruppe auf Lücke zu CF2 steht und C1 Symmetrie, falls eine S—F und eine S=O Bindung auf Lücke zu CF2 stehen. Die experimentellen Elektronenbeugungsintensitäten können mit einem C1 Konformeren oder mit einem Gemisch aus C2v, C2 und Cs Konformeren im Verhältnis 3:2:5 nahezu gleich gut angepaßt werden. Die folgenden geometrischen Parameter (ra Abstände und ∠α Winkel mit 3σ Fehlergrenzen) wurden erhalten: C—F = 1,340(6) Å, S=O = 1,412(2) Å, S—F = 1,550(3) Å, C—S = 1,848(4) Å, S—C—S = 113,6(7)°, F—C—F = 110,0(10)°, O=S=O = 124,6(18)°, C—S—F = 96,5(16)° und C—S=O = 108,4(14)°.
    Notes: New synthetic pathways and the infrared spectrum of bis(fluorosulfonyl)difluoromethane, (SO2F)2CF2, are reported. The geometric structure and conformational properties of the title compound have been studied by gas electron diffraction. Depending on the rotational position of the two SO2F groups, four conformers with different symmetries can occur in this compound: C2v symmetry, if both S—F bonds stagger the CF2 group. C2 or Cs symmetry, if one S=O bond of each group staggers the CF2 group. The experimental electron diffraction intensities can be fitted equally well with a C1 conformer or with a mixture of C2v, C2 and Cs conformers, in a ratio of 3:2:5. The following geometric parameters (ra distances, ∠α angles with 3σ uncertainties) were derived: C—F = 1.340(6) Å, S=O = 1.412(2) Å, S—F = 1.550(3) Å, C—S = 1.848(4) Å, S—C—S = 113.6(7)°, F—C—F = 110.0(10)°, O=S=O = 124.6(18)°, C—S—F = 96.5(16)° and C—S=O = 108.4(14)°.
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  • 38
    ISSN: 0044-2313
    Keywords: Chromium niobate ; chemical transport reactions ; block structure ; high resolution electron microscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Investigation of Inorganic Non-Stoichiometric Compounds. XLIII. Preparation and Electron Microscopic Investigation of (Cr, Nb)12O29Transport experiments in the system Cr/Nb/O yielded the compound (Cr, Nb)12O29 as crystalline green needles. The lattice parameters of the monoclinic cell are a = 31.162(8) Å, b = 3.8324(6) Å, c = 20.579(6) Å, β = 113.22(3)°. (Cr, Nb)12O29 is isotypic with monoclinic Nb12O29 as shown by Guinier diagrams and high resolution transmission electron microscopy. Characteristic structural building elements are [3 × 4]-blocks which are columnar sections from the ReO3 structure. In the real structure one finds numerous defects. Under the influence of the electron beam we observed reversible changes of contrast which indicates that the positions of the M-particles (M = Cr, Nb) have shifted.
    Notes: Grüne, nadelförmige Kristalle von monoklinem (Cr, Nb)12O29 entstanden bei Transportexperimenten im System Cr/Nb/O. Die Gitterparameter a = 31,162(8) Å, b = 3,8324(6) Å, c = 20,579(6) Å, β = 113,22(3)° aus Guinieraufnahmen zeigen ebenso wie Strukturabbildungen mit der hochauflösenden Durchstrahlungselektronenmikroskopie Isotypie zu monoklinem Nb12O29. Auf den Aufnahmen erkennt man als charakteristisches Bauelement [3 × 4]-Blöcke, säulenförmige Ausschnitte aus der ReO3-Struktur, sowie zahlreiche Baufehler. Reversible Veränderungen des Kontrastes unter der Einwirkung des Elektronenstrahls lassen auf Änderungen der M-Positionen (M = Cr, Nb) schließen.
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  • 39
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 847-850 
    ISSN: 0044-2313
    Keywords: Diorganoindium cations ; syntheses ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diorganoindium Cations. The Crystal Structure of [Mes2In][BF4](PhCH3)2In and Mes3In react with BF3 · OEt2 in a ratio of 3:4 at 80°C in toluene to the corresponding salts [R2In][BF4] [R = PhCH2 (1), Mes (2)]. The same results could be obtained, when the diorganoindium fluorides (PhCH2)2InF and Mes2InF were treated with BF3 · OEt2 at 80°C in toluene. 1 und 2 were characterized by NMR-, IR- und MS-techniques. The arrangement of the ions in 2 could be established by an X-ray structure determination. The cations and anions of 2 are forming infinite chains. The metal centers are coordinated by two BF4--ions, so that every In atom possesses a distorted octahedral coordination sphere.
    Notes: (PhCH2)3In und Mes3In reagieren mit BF3 · OEt2 im Verhältnis 3:4 bei 80°C in Toluol zu den entsprechenden Salzen [R2In][BF4] [R = PhCH2 (1), Mes (2)]. Zum selben Ergebnis gelangt man, wenn die Diorganoindiumfluoride (PhCH2)2InF und Mes2InF mit BF3 · OEt2 bei 80°C in Toluol behandelt werden. 1 und 2 wurden mittels NMR- und IR-Spektroskopie sowie Massenspektrometrie charakterisiert. Die Anordnung der Ionen in 2 konnte durch eine Röntgenstrukturanalyse aufgeklärt werden. 2 bildet danach unendliche Ketten aus Kationen und Anionen, wobei durch eine chelatartige Anordnung zweier BF4--Ionen an jedes Metallzentrum eine verzerrt oktaedrische Koordinationssphäre der Indiumatome resultiert.
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  • 40
    ISSN: 0044-2313
    Keywords: System lithium hydroxide/lithium iodide ; crystal structure of Li2I(OH) and Li5I(OH)4 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Li2I(OH): A Compound with Onedimensional Infinite Edge Sharing [Li4/2(OH)+] PyramidsThe pseudobinary system LiOH/LiI was investigated by X-ray methods. Two compounds, Li2I(OH) and Li5I(OH)4 exist. The structure of Li2I(OH) was solved by single-crystal data. For Li5I(OH)4 lattice constants and space group symmetry are given:Li2I(OH): Pnma, Z = 4, a = 10.339(4) Å, b = 5.567(1) Å, c = 6.643(2) Å, Z(Fo) mit (Fo)2 ≧ 3σ(Fo)2 = 439, Z (parameter) = 23, R/Rw = 0.030/0.040Li5I(OH)4: Pmmn or P21mn(= Pmn21), Z = 2, a = 10.42 Å, b = 5.30 Å, c = 5.81 ÅLi2I(OH) crystallizes in a new type of structure. The motif of a distorted hexagonal close-packed arrangement of iodide ions is penetrated by chains of ∞1[Li4/2(OH)+].
    Notes: Das pseudobinäre System LiOH/LiI wurde röntgenographisch untersucht. Es gibt zwei Verbindungen, Li2I(OH) und Li5I(OH)4. Die Struktur von Li2I(OH) wurde mittels Einkristallröntgenstrukturanalyse aufgeklärt, von Li5I(OH)4 konnte die Elementarzellmetrik und Symmetrie ermittelt werden:Li2I(OH): Pnma, Z = 4, a = 10,339(4) Å, b = 5,567(1) Å, c = 6,643(2) Å, Z(Fo) mit (Fo)2 ≧ 3σ(Fo)2 = 439, Z (Parameter) = 23, R/Rw = 0,030/0,040Li5I(OH)4: Pmmn oder P21mn(= Pmn21), Z = 2, a = 10,42 Å, b = 5,30 Å, c = 5,81 ÅLi2I(OH) kristallisiert in einem eigenen Strukturtyp, dem das Motiv einer verzerrten hexagonal dichtesten Anordnung von Iodidionen zugrunde liegt, die von Strängen aus ∞1[Li4/2(OH)+] durchdrungen wird.
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  • 41
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 479-482 
    ISSN: 0044-2313
    Keywords: System lithium amide/lithium bromide ; crystal structure of Li2Br(NH2) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Li2Br(NH2): The First Ternary Alkali Metal Amide HalideThe pseudobinary system LiNH2/LiBr was investigated by X-ray methods. The crystal structure of the compound Li2Br(NH2) was solved by single crystal data:Li2Br(NH2): Pnma, Z = 8, a = 12.484(2) Å, b = 7.959(1) Å, c = 6.385(1) Å, Z(Fo) with (Fo)2 ≧ 3σ(Fo)2 = 348, Z (parameter) = 51, R/Rw = 0.019/0.021Li2Br(NH2) crystallizes in a new type of structure. To one another isolated chains of ∞1[Li2Li4/2(NH2)22+] show the motif of closest rod packing. They are connected via bromide ions in a distorted cubic primitive arrangement.
    Notes: Das pseudobinäre System LiNH2/LiBr wurde röntgenographisch untersucht. Die Struktur einer Verbindung, Li2Br(NH2), wurde mittels Einkristallröntgenstrukturanalyse aufgeklärt:Li2Br(NH2): Pnma, Z = 8, a = 12,484(2) Å, b = 7,959(1) Å, c = 6,385(1) Å, Z(Fo) mit (Fo)2 ≧ 3σ(Fo)2 = 348, Z (Parameter) = 51, R/Rw = 0,019/0,021Die Verbindung kristallisiert in einem eigenen Strukturtyp. Von ihresgleichen isolierte Stränge aus ∞1[Li2Li4/2(NH2)22+] bilden eine dem Motiv nach dichteste Stabpackung. Bromidionen verknüpfen die Stäbe in verzerrt kubisch primitiver Anordnung.
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  • 42
    ISSN: 0044-2313
    Keywords: Dithiatetrazine ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung und Röntgenstrukturanalyse von 1,4,2,3,5,6-DithiatetrazinDie Umsetzung von Schwefeldichlorid mit sym-EtO2CNHNHCO2Et 1 ergibt S2[N(CO2Et)]4 2, das analytisch, durch NMR und röntgenographisch charakterisiert wird. Die Strukturanalyse von 2 zeigt, daß der S2N4-Ring Sessel-Konformation hat mit allen vier Estergruppen in pseudoaxialen Positionen. Die Bindungslängen und -winkel werden mit denen in 1 und S4(NR)2 verglichen.
    Notes: Reaction of sulfur dichloride with sym-EtO2CNHNHCO2Et 1 gives the title ring system which has been characterised by microanalyses, nmr, and X-Ray crystallography. The X-ray structure of S2[N(CO2Et)]4 2 reveals that the S2N4 ring adopts a chair conformation with all four ester groups in pseudo-axial positions. Bond lengths and angles are compared with 1 and S4(NR)2.
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  • 43
    ISSN: 0044-2313
    Keywords: o-1λ5,3λ5-Diphosphaphenylene-bis(diphenylphosphane) ; nickel(II) chloride chelate complex ; crystal structure ; NMR, Ir spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: o-1λ5,3λ5-Diphosphaphenylene-bis(diphenylphosphane) and its Chelating PropertiesBis(diphenylphosphanyl)acetylene and 1,1′,3,3′-tetrakis(dimethylamino)-1λ5,3λ5-diphosphete react at higher temperatures to yield the title compound 5, which forms easily the chelate complex 6 with nickel(II) chloride.
    Notes: Bis(diphenylphosphanyl)acetylen und 1,1′,3,3′-Tetrakis(dimethylamino)-1λ5,3λ5-diphosphet reagieren bei höheren Temperaturen zur Titelverbindung 5, die mit Nickel(II)-chlorid leicht den Chelatkomplex 6 bildet.
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  • 44
    ISSN: 0044-2313
    Keywords: Thiooxalates ; 1,1-Dithiooxalate ; 1,1-Dithiooxalic ester ; transition metal complex ; Crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,1-Dithiooxalic Acid Derivatives as Ligands in Transition Metal Complexes: Structure of O-Methyl-1,1-dithiooxalato-bis(triphenylphosphine)copper(I) and silver(I)Despite O-Alkyl-1,1-dithiooxalates are also tetradentate thioligands their tendency towards the formation of multi-nuclear bridged chelates as found for the basic 1,1-dithiooxalate does practically not exist because of derivatisation. The reaction with triphenylposphinemetal(I)-halogenides yields defined mono-nuclear mixed ligand complexes: O-Methyl-1,1-dithiooxalato-bis(triphenylphosphine)copper(I) (2) and silver(I) (1). X-ray analysis shows that both complexes (1 and 2) are isostructural and crystallize in the monoclinic space group P21/n: (Ph3P)2Ag(S2C2O2Me) (1) with a = 12.794(1), b = 21.314(4), c = 13.560(1) Å, β = 97.983(6)°, and (Ph3P)2Cu(S2C2O2Me) (2) with a = 12.622(1), b = 21.196(2), c = 13.426(1) Å, β = 96.533(7)°. These complexes are the first authentic examples of exclusively end-on coordinated thiooxalate.
    Notes: Obwohl potentiell auch vierzähnig, ist die Tendenz von O-Alkyl(bzw. Aryl)-1,1-dithio-oxalaten zur Ausbildung von Brücken in Mehrkern-Chelaten durch die Derivatisierung gegenüber dem Stammliganden 1,1-Dithiooxalat praktisch nicht mehr vorhanden. Durch Umsetzung mit Triphenylphosphinmetall(I)-halogeniden sind definierte einkernige Gemischtligandenkomplexe zugänglich. O-Methyl-1,1-dithiooxalato-bis(triphenylphosphin)kupfer(I) und -silber(I) konnten mittels Röntgenkristallstrukturanalyse strukturell gesichert werden. Beide Komplexe sind isostrukturell und kristallisieren in der monoklinen Raumgruppe P21/n: (Ph3P)2Ag(S2C2O2Me) (1), mit a = 12,794(1), b = 21,314(4), c = 13,560(1) Å, β = 97,983(6)° und (Ph3P)2Cu(S2C2O2Me) (2), mit a = 12,622(1), b = 21,196(2), c = 13,426(1) Å, β = 96,533(7)°. Diese beiden Komplexe sind die ersten strukturell gesicherten Vertreter mit ausschließlich end-on koordiniertem Thiooxalat.
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  • 45
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 505-508 
    ISSN: 0044-2313
    Keywords: O-methyl-1,1-dithiooxalate ; nucleophilic attack on dithiocarbon ; perthio ligand ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Surprising Reactions on O-Methyl-1,1-dithiooxalatesThe O-methyl-1,1-dithiooxalate ligand (i-dtoMe) reacts with metalII-acetylacetonates of d8 metal centers (NiII, PdII) forming mononuclear mixed ligand complexes with two remarkable aspects: The formation of a perthioligand, first time described for thiooxalates, and the first example of a nucleophilic attack of a CH-acidic compound (acetylacetonate) on dithiocarbon of coordinated dithiocompounds (here i-dtoMe). X-ray structure is shown for Ph4P[(ptoMe)Ni(i-dtoMeacac)].
    Notes: O-Methyl-1,1-dithiooxalat (i-dtoMe) reagiert mit Acetylacetonatkomplexen von d8-Metallen (NiII, PdII) unter Bildung von einkernigen Gemischtligandenkomplexen Ph4P[(ptoMe)M(i-dtoMeacac)] unerwarteter Konstitution. Durch Röntgenkristallstrukturanalyse des NiII-Komplexes konnte erstmals ein nukleophiler Angriff einer CH-aciden Verbindung (Acetylacetonat) am Dithiokohlenstoff einer koordinativ gebundenen Dithioverbindung (i-dtoMe) nachgewiesen werden.Gefunden wurde weiterhin die Entstehung einer Perthiogruppierung, die bisher für Thiooxalate bzw. deren Derivate unbekannt war.
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  • 46
    ISSN: 0044-2313
    Keywords: K2Fe[P2S6] ; Hexathiodiphosphate(IV) ; Hexathiohypodiphosphate ; Crystal Structure ; Magnetism ; Vibrational Spectrum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese, Kristallstruktur, Magnetismus und Schwingungsspektrum von Dikaliumeisen(II)hexathiodiphosphat(IV), K2Fe[P2S6]K2Fe[P2S6] wurde aus den Elementen bei 1173 K in evakuierten, abgeschmolzenen Quarzampullen dargestellt. Die Verbindung bildet transparente, orangefarbene, luft- und feuchtigkeitsbeständige Kristalle. K2Fe[P2S6] kristallisiert monoklin, Raumgruppe P21/n (Nr. 14), mit den Gitterkonstanten (T = 298,5 K): a = 6,0622(4), b = 12,172(1) und c = 7,3787(8) Å, β = 101,113(7)°, Z = 2. Der neuartige Strukturtyp (mP22) wird durch Säulen von alternierend flächenverknüpften S6-Oktaedern und trigonalen Antiprismen (beide verzerrt) charakterisiert, die parallel zur a-Achse verlaufen und durch K+-Kationen (KZ 10; {2,6,2}-Polyeder; d(K—S) = 3,231 - 3,845 Å) miteinander verbunden sind. Die S6-Polyeder der Säulen werden alternierend durch Fe (d̄(Fe—S) = 2,577 Å) bzw. P2-Paare zentriert, die zur a-Achse um 73,4° geneigt sind. Die Bindungslängen in den Hexathiodiphosphat(IV)-Anionen [P2S6]4- mit angenäherter 32/m - D3d-Symmetrie betragen d(P—P) = 2,20 und d̄(P—S) = 2,02 Å. Die Titelverbindung ist oberhalb TN = 28 K paramagnetisch mit μ = 4,69 B.M. und ordnet unterhalb TN antiferromagnetisch. Die beobachteten inneren Moden der Raman- und Infrarotspektren von K2Fe[P2S6] stehen im Einklang mit der Faktorgruppenanalyse. Die Schwingungsbanden werden auf der Basis von [P2S6]4--Einheiten unter Berücksichtigung der Abweichungen von der D3d-Symmetrie zugeordnet.
    Notes: K2Fe[P2S6] was synthesized from the elements at 1173 K in sealed quartz tubes. The compound forms transparent orange crystals, stable against air and moisture. K2Fe[P2S6] crystallizes in the monoclinic system, space group P21/n (No. 14), with cell dimensions (T = 298.5 K) a = 6.0622(4), b = 12.172(1) and c = 7.3787(8) Å, β = 101.113(7)°, Z = 2. The novel structure type (mP22) is characterized by columns of alternating face-sharing S6 octahedra and trigonal antiprisms (both distorted) parallel to the a axis, which are interconnected by inserted K+ (CN 10; {2,6,2}-polyhedra; d(K—S) = 3.231 - 3.845 Å). The S6 polyhedra of the columns are centered alternately by Fe (d̄(Fe—S) = 2.577 Å) and P2 pairs which are inclined to the a axis by 73.4°. The bond lengths in the hexathiodiphosphate(IV) anions, [P2S6]4-, with approximate 3 2/m - D3d symmetry, are d̄(P—P) = 2.20 and d̄(P—S) = 2.02 Å. The compound is paramagnetic above TN = 28 K with μ = 4.69 B.M. and orders antiferromagnetically below TN. The internal modes of the observed Raman and FIR spectra of K2Fe[P2S6] are in accord with the factor group analysis, and the spectra are assigned on the basis of [P2S6]4- units, taking into account the deviation from D3d symmetry.
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  • 47
    ISSN: 0044-2313
    Keywords: (difluoro)methylphosphine ; (difluoro)methylphosphonium salts ; preparation ; single crystall X-ray structure ; vibrational and NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Structures of CH3PF2H+AsF6- and CH3PF2H+SbF6- and a simple Method for Preparation of CH3PF2A simple method for preparation of CH3PF2 from CH3PCl2 is reported. The phosphonium salts CH3PF2H+MF6- are obtained by the reaction of CH3PCl2 with superacidic systems HF/MF5 (M = As, Sb). CH3PF2H+SbF6- crystallizes in the space group P1 with a = 548.4(4) pm, b = 695.5(8) pm, c = 960.2(9) pm, α = 94.68(5)°, β = 97.19(6)°, γ = 94.41(6)° and Z = 2. CH3PF2H+SbF6- crystallizes in P1 with a = 554.3(3), b = 724.2(4), c = 970.4(5), α = 94.73(4)°, β = 96.14(5)°, γ = 95.30(4)°.
    Notes: Es wird über eine einfache Darstellung von CH3PF2 aus CH3PCl2 berichtet, welches in den supersauren Systemen HF/MF5 (M = As, Sb) zu den Phosphoniumsalzen CH3PF2H+MF6- protoniert wird. CH3PF2H+AsF6- kristallisiert in der Raumgruppe P1 mit a = 548,4(4) pm, b = 695,5(8) pm, c = 960,2(9) pm, α = 94,68(5)°, β = 97,19(6)°, γ = 94,41(6)° und Z = 2, das isostrukturelle CH3PF2H+SbF6- mit a = 554,3(3), b = 724,2(4), c = 970,4(5), α = 94,73(4)°, β = 96,14(5)°, γ = 95,30(4)°.
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  • 48
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 519-522 
    ISSN: 0044-2313
    Keywords: Zirconium complexes ; diazabutadiene ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zirconium Diazabutadiene Complexes of the Type Zr(DAD)31,4-Diazabutadienes (DAD), RN=CPh—CPh=NR 1 (R = C6H5 a, CH3C6H4 b, CH3OC6H4 c), react with ZrCl4 · 2 THF with formation of complexes of the type ZrCl4 · DAD 2. At interaction with lithium diazadienides Li2DAD deep coloured complexes of the composition Zr(DAD)3 3 are formed.The new compounds were characterized by elemental analysis, i.r., 1H- and 13C-n.m.r. spectra.
    Notes: 1,4-Diazabutadiene (DAD), RN=CPh—CPh=NR 1 (R=C6H5 a, CH3C6H4 b, CH3OC6H4 c), reagieren mit ZrCl4 · 2 THF zu Addukten der Zusammensetzung ZrCl4 · DAD 2. Diese werden bei Einwirkung von Lithiumdiazadieniden Li2DAD in tieffarbige Komplexe des Typs Zr(DAD)3 3 übergeführt.Die erhaltenen Verbindungen wurden durch Elementaranalysen sowie ihre IR-, 1H- und 13C-NMR-Spektren charakterisiert.
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  • 49
    ISSN: 0044-2313
    Keywords: N-Trifluormethyl-difluormethyleneiminium salts ; preparation ; n.m.r., i.r. spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of the Iminium Salts CF3—NX=CF2+MF6- (X = CH3, F and M = As, Sb) and CF3—NCl=CF2+ AsF6-The preparation of the iminiumsalts CF3—NX=CF2+ MF6- (X = CH3, F and M = As, Sb) and CF3—NCl=CF2+ AsF6- is reported. The salts were characterized by NMR and infrared spectroscopy. CF3—NCH3=CF2+MF6- decompose into MF5 and (CF3)2NCH3.
    Notes: Es wird über die Darstellung der Iminiumsalze CF3—NX=CF2+ MF6- (X = CH3, F und M = As, Sb) und CF3—NCl=CF2+AsF6- berichtet. Die Salze werden durch NMR- und IR-Spektroskopie charakterisiert. CF3—NCH3=CF2+MF6- zerfällt in MF5 und (CF3)2NCH3.
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  • 50
    ISSN: 0044-2313
    Keywords: Tetramethyltitanium-1,2-bis(dimethylphosphino)-ethane ; NMR data ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Transition Metal Alkyl Compounds. 61. Preparation and Crystal Structure of Tetramethyltitanium-1,2-bis(dimethylphosphino)ethaneThe title complex 1 was synthesized by addition of 1,2-bis(dimethylphosphino)ethane to a solution of tetramethyltitanium in diethylether. The complex was characterized by 1H, 13C and 31P NMR spectra and by X-ray crystal structure analysis. 1 consists of two independent molecules with distorted octahedral structure.
    Notes: Der Titelkomplex 1 wurde durch Addition von 1,2-Bis(dimethylphosphino)ethan an Tetramethyltitan in Diethylether erhalten. Der Komplex wurde 1H-, 13C- und 31P-NMR-spektroskopisch, sowie durch Röntgenkristallstruktur-analyse charakterisiert. 1 tritt in der Elementarzelle in zwei unabhängigen Molekülen mit verzerrt oktaedrischer Konstitution auf.
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  • 51
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 527-530 
    ISSN: 0044-2313
    Keywords: Barium ; rare earth ; zinc ; oxide ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Chemistry of a New Barium Rare-Earth Oxozincate: Ba2Er2Zn8O13High temperature reactions led to single crystals of Ba2Er2Zn8O13. It crystallizes with orthorhombic symmetry, space group C122v—Cmc21, a = 6.276, b = 10.871, c = 10.195 Å, Z = 2. The hitherto unknown crystal structure shows Zn2+ with tetrahedral, Er3+ octahedral and Ba2+ cuboctahedral coordination by O2-. It will be shown that parts of the [Zn8O13] network are fragments of the ZnO structure showing O2- within a tetrahedral zinc coordination. A deficit of two O2- ions per unit cell is focused on two point positions.
    Notes: Durch Hochtemperaturreaktionen wurden Einkristalle von Ba2Er2Zn8O13 dargestellt und anschließend röntgenographisch untersucht. Die Verbindung kristallisiert in einem neuen Strukturtyp mit orthorhombischer Symmetrie, Raumgruppe C122v—Cmc21; a = 6,276; b = 10,871; c = 10,195 Å; Z = 2. Die bisher unbekannte Kristallstruktur zeigt Zn2+ in tetraedrischer, Er3+ in oktaedrischer und Ba2+ in kuboktaedrischer Koordination von O2-. Es wird gezeigt, daß das [Zn8O13]-Gerüst Fragmente der ZnO-Struktur mit O2- in tetraedrischer Zinkkoordination enthält. Ein Defizit von zwei O2 pro Elementarzelle verteilt sich auf zwei Punktlagen.
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  • 52
    ISSN: 0044-2313
    Keywords: Cesium tetraimidophosphate-diamide ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of a Cesium-tetraimidophosphate-diamide, Cs5[P(NH)4](NH2)2 = Cs3[P(NH)4] · 2 CsNH2Well crystallized Cesium-tetraimidophosphate-diamide is obtained by the reaction of CsNH2 with P3N5 in autoclaves at 673 K within three days. X-ray single crystal investigations led to the following dataCcca, Z = 4, a = 8.192(5) Å, b = 20.472(5) Å,c = 8.252(3) ÅZ(F2o) ≥3σ(F2o) = 916, Z(Var.) = 32, R/Rw=1 = 0.017/0.021The compound contains the hitherto unknown anion [P(NH)4]3-.
    Notes: Gut kristallisiertes Caesium-tetraimidophosphat-diamid entsteht bei der Umsetzung von CsNH2 mit P3N5 in Autoklaven bei 673 K innerhalb von drei Tagen. Röntgenographische Untersuchungen an Einkristallen der Verbindung ergaben:Ccca, Z = 4, a = 8,192(5) Å, b = 20,472(5) Å,c = 8,252(3) ÅZ(F2o) ≥ 3σ(F2o) = 916, Z(Var.) = 32, R/Rw=1 = 0,017/0,021Die Verbindung enthält das bis dahin unbekannte Anion [P(NH)4]3-.
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  • 53
    ISSN: 0044-2313
    Keywords: Sodium tetraoxo nitrido tungstate(VI) ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of Sodium Tetraoxo Nitrido Tungstate(VI), Na5WO4NColourless crystals of Na5WO4N are obtained besides Na4WO2N2 [1] by the reaction of WO3 with NaNH2 (15:1) at 350°C ≥ T ≥ 750°C in autoclaves to prevent early decomposition of sodium amide. X-ray single crystal investigations are characterized by the following data:Na5WO4N: Cmc21 (No. 36), Z = 4a = 9.873(2) Å, b = 5.769(1) Å, c = 10.648(2) ÅZ(F2o)≥ 3σ(F2o) = 2182, Z(Var.) = 55, R/Rw = 0.029/0.039The structure contains the tetragonal pyramidal ion WO4N5- with nitrogen at the apex connected via Na+ ions irregularly coordinated by one nitrogen and four oxygen atoms of different anions.
    Notes: Farblose Kristalle von Na5WO4N entstehen neben Na4WO2N2 [1] bei der Umsetzung von WO3 mit NaNH2 (15:1) bei 350°C ≥ T ≥ 750°C in Autoklaven, die eine frühzeitige Zersetzung von Natriumamid verhindern. Die röntgenographische Strukturbestimmung an Einkristallen ist durch folgende Daten charakterisiert:Na5WO4N: Cmc21 (Nr. 36), Z = 4a = 9,873(2) Å, b = 5,769(1) Å, c = 10,648(2) ÅZ(F2o) ≥ 3σ(F2o) = 2182, Z(Var.) = 55, R/Rw = 0,029/0,039Die Struktur enthält das tetragonal pyramidale Ion WO4N5 mit Stickstoff in apikaler Position. Die Anionen sind durch Na+-Ionen verknüpft, die unregelmäßig von einem N- und vier O-Atomen unterschiedlicher Anionen koordiniert sind.
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  • 54
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 551-560 
    ISSN: 0044-2313
    Keywords: Metal complexes ; Amidines ; Oxalic derivates ; Imidazolidines ; Diazadiene ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nitrogen Derivates of Oxalic Acid as New Complexing AgentsHeterocycles with a exocylic 1,4-diaza-1, 3-diene structure 5a-d have σ-bonding and π-backbonding properties similar to the diazadienes (DAD) 1. The investigations of the molybdenum complexes 11 and 12 of the ligands 5 show a dominant σ-interaction and only a small π-backbonding, comparable with the compound (CO)4Mo(iPYC) 14, a complex of pyridinecarbaldehyde isopropylimine (iPYC).The oxalamidine (TPOA) 4 (precursor of the heterocycles 5a-d) are present in a s-trans (E/E)-form with two stable intra-molecular hydrogen bridges. 4 reacts with ferrous and cobaltous chloride to the polymer coordination compounds 8 and 9. According to the diazadiene 1 oxalamadine 4 substitutes two carbonyls in Mo(CO)6 by formation of (CO)4Mo(TPOA) 10. The coordinated ligand 4 shows in the complex 10 a s-cis(E/E)-form with respect to the free ligand and no H-bridges were observed. The crystal structures of TPOA 4 and (CO)4Mo(TPOA) 10 were determined. Cyclisation reactions on the coordinated oxalamidine are possible.
    Notes: Heterocyclen mit einer exocyclischen 1,4-Diaza-1,3-dien-Struktur 5a-d besitzen in Analogie zu den Diazadienen (DAD) 1 α-Donor und π-Akzeptoreigenschaften. Durch vergleichende Untersuchungen an deren Molybdäncarbonylkomplexen 11 und 12 konnte festgestellt werden, daß der σ-Bindungscharakter dominant ist und nur geringe π-Rückbindungsanteile vorliegen, vergleichbar mit Verbindung (CO)4Mo(iPYC) 14, einem Komplex des Pyridin-2-carbaldehyd-isopropylimins (iPYC).Der Vorläufer dieser Heterocyclen, das Oxalamidin 4 (TPOA), liegt als Molekül in einer s-trans-(E/E)-Form mit zwei stabilen intramolekularen Wasserstoffbrücken vor. 4 bildet mit Eisen(II)- bzw. Cobalt(II)-chloriden polymere Koordinationsverbindungen 8 und 9. Mit Molybdänhexacarbonyl reagiert 4 analog den Diazadienen 1 unter Substitution zweier Carbonyl-gruppen zu (CO)4Mo(TPOA) 10. In 10 liegt der Ligand 4 in der s-cis-(E/E)-Form vor, wobei keine Wasserstoffbrücken-bindungen mehr beobachtet werden. Von 4 und 10 wurden Röntgenstrukturanalysen angefertigt. Am koordinativ fixierten Oxalamidin in 10 können Cyclisierungsreaktionen durchgeführt werden.
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  • 55
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 561-565 
    ISSN: 0044-2313
    Keywords: Ternary palladium phosphide ; erbium ; crystal structure ; band calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Er3Pd7P4  -  Crystal Structure Determination and Extended Hückel CalculationsEr3Pd7P4 was prepared by heating the elements (1050°C) and investigated by means of single-crystal X-ray methods. The compound crystallizes in a new structure (C2/m; a = 15.180(3) Å, b = 3.955(1) Å, c = 9.320(1) Å, β = 125,65(1)°; Z = 2) with a three-dimensional framework of Pd and P atoms and with Er atoms in the holes. The Pd atoms are surrounded tetrahedrally, trigonally or linearly by P atoms, which are coordinated by nine metal atoms in the form of a tricapped trigonal prism. Therefore the atomic arrangement of Er3Pd7P4 is related to the structures of ternary transition metal phosphides with a metal: phosphorus ratio of 2:1. Band calculations using the Extended Hückel method show strong covalent Pd—P bonds and weak bonding interactions between Pd atoms with Pd—Pd distances shorter than 2.9 Å.
    Notes: Er3Pd7P4 wurde durch Erhitzen der Elemente auf 1050°C dargestellt und röntgenographisch mit Einkristallmethoden untersucht. Die Verbindung kristallisiert monoklin (C2/m; a = 15,180(3) Å, b = 3,955(1) Å, c = 9,320(1) Å, β = 125,65(1)°; Z = 2) in einer neuen Struktur mit einem dreidimensionalen Gerüst aus Pd- und P-Atomen, in dessen Lücken sich die Er-Atome befinden. Die P-Umgebung der Pd-Atome ist tetraedrisch, trigonal oder linear. Die P-Atome ihrerseits werden von 9 Metallatomen in Form eines dreifach überkappten trigonalen Prismas koordiniert. Der Aufbau von Er3Pd7P4 ist dementsprechend verwandt mit den Strukturen ternärer Übergangsmetall-Phosphide mit einem Metall: Nichtmetallverhältnis von 2:1. Extended Hückel Rechnungen zeigen u. a. neben starken kovalenten Pd—P-Bindungen schwache bindende Wechselwirkungen zwischen denjenigen Pd-Atomen, deren Abstände voneinander kürzer als 2,9 Å sind.
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  • 56
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 539-544 
    ISSN: 0044-2313
    Keywords: Ionic arsen- and antimony(III)-dithiocarbamates ; synthesis ; vibrational and mass spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dimethyldithiocarbamatoarsanes and -stibanesThe Halogeno-bis(dimethyldithiocarbamato)-compounds (dtc)2AsCl 1, (dtc)2AsBr 2, (dtc)2AsI 3 and (dtc)2SbI 4 are prepared from (dtc)3As and (dtc)3Sb resp. Reaction of 1 to 4 with CF3SO3Sime3 yields the ionic compounds (dtc)2As+CF3SO3- 5 and [(dtc)2El+]2Hal-(CF3SO3-) · CH2Cl2 6 (El = As; Hal = I), 7 (El = Sb; Hal = I) and 8 (El = As; Hal = Br) resp. by elimination of me3SiHal. The mass spectra and the main fragmentation from 1 to 8 are reported. The vibrational spectra of these compounds, of As(dtc)3, Sb(dtc)3 and of the antimony compounds which are corresponding to 6 and 8 are discussed.
    Notes: Die Synthese der Halogeno-bis(dimethyldi-thiocarbamato)-Verbindungen (dtc)2AsCl 1, (dtc)2AsBr 2, (dtc)2AsI 3 und (dtc)2SbI 4 aus (dtc)3As bzw. (dtc)3Sb wird beschrieben. Umsetzungen von 1 bis 4 mit CF3SO3Sime3 führen unter me3SiHal-Abspaltung zu den salzartigen Verbindungen (dtc)2As1CF3SO3 5 bzw. [(dtc)2El1]2Hal (CF3SO3) · CH2Cl2 6 (El = As; Hal = I), 7 (El = Sb; Hal = I) und 8 (El = As; Hal = Br). Die Massenspektren und die Hauptzerfallswege von 1 bis 8 werden mitgeteilt. Die Schwingungsspektren von 1 bis 8, As(dtc)3, Sb(dtc)3 sowie den 6 und 8 entsprechenden Antimonverbindungen werden diskutiert.
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  • 57
    ISSN: 0044-2313
    Keywords: Ether-phosphanes ; ruthenium complexes ; polysiloxane-matrices ; heteronuclear CP-MAS NMR spectroscopy, Chemical Shift Anisotropy (CSA) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Supported Organometallic Complexes. VI. Characterization und Reactivity of Polysiloxane-Bound (Ether-phosphane)ruthenium(II) ComplexesThe ligands PhP(R)CH2D [R = (CH3O)3Si(CH2)3; D = CH2OCH3 (1b); D = tetrahydrofuryl (1c); D = 1,4-dioxanyl (1d)] have been used to synthesize (ether-phosphane)ruthenium(II) complexes, which have been copolymerized with Si(OEt)4 to yield polysiloxane-bound complexes. The monomers cis,cis,trans-Cl2Ru(CO)2(P ∼ O)2 (3b) and HRuCl(CO)(P ∼ O)3 (5b) were treated with NaBH4 to form cis,cis,trans-H2Ru(CO)2(P ∼ O)2 (4b) and H2Ru(CO)(P ∼ O)3 (6b), respectively (P ∼ O = η1-P coordinated; = η2- coordinated). Addition of Si(OEt)4 and water leads to a base catalyzed hydrolysis of the silicon alkoxy-functions and a precipitation of the immobilized counterparts 4b′, 6b′. The polysiloxane matrix resulting by this new sol gel route has been described under quantitative aspects by 29Si CP-MAS NMR spectroscopy. 4b′ reacts with carbon monoxide to form Ru(CO)3(P ∼ O)2 (7b′). Chelated polysiloxane-bound complexes Cl2Ru()2 (9c′, d′) and Cl2Ru()(P ∼ O)2 (10b′, c′) have been synthesized by the reaction of 1b-c with Cl2Ru(PPh3)3 (8) followed by a copolymerization with Si(OEt)4. The polysiloxane-bound complexes 9c′, d′ and 10b′, c′ react with one equivalent of CO to give Cl2Ru(CO)()(P ∼ O) (12b′-d′). Excess CO leads to the all-trans-complexes Cl2Ru(CO)2(P ∼ O)2 (14b′-d′), which are thermally isomerized to cis,cis,trans-3b′-d′. The chemical shift anisotropy of 31P in crystalline Cl2Ru()2 (9a, R = Ph, D = CH2OCH3) has been compared with polysiloxane-bound 9d′ indicating a non-rigid behavior of the complexes in the matrix.
    Notes: Mit den Liganden PhP(R)CH2D [R = (CH3O)3Si(CH2)3; D = CH2OCH3: (1b); D = Tetrahydrofuryl (1c); D = 1,4-Dioxanyl (1d)] sind (Ether-phosphan)ruthenium(II)-Komplexe zugänglich, die durch Copolymerisation mit Si(OEt)4 in die entsprechenden Polysiloxan-gebundenen Spezies überführt werden. Die löslichen Komplexe cis,cis,trans-Cl2Ru(CO)2(P ∼ O)2 (3b) und HRuCl(CO)(P ∼ O)3 (5b) werden mit NaBH4 zu cis,cis,trans-H2Ru(CO)2(P ∼ O)2 (4b) bzw. H2Ru(CO)(P ∼ O)3 (6b) umgesetzt (P ∼ O = η1-P koordiniert; = η2- koordiniert). Zugabe von Si(OEt)4 und Wasser führt zu einer basenkatalysierten Hydrolyse der Alkoxygruppen am Silicium und zur Abscheidung der immobilisierten Komplexe 4b′, 6b′. Die durch diese Sol-Gel-Variante gebildete Polysiloxanmatrix wird 29Si—CP-MAS-NMR-spektroskopisch durch Quantifizierung der auftretenden Silylspezies beschrieben. 4b′ reagiert mit Kohlenmonoxid zu Ru(CO)3(P ∼ O)2 (7b′). Polysiloxan-gebundene Chelat-Komplexe des Typs Cl2Ru()2 (9c′, d′) und Cl2Ru()(P ∼ O)2 (10b′, c′) sind durch Reaktion von 1b-c mit Cl2Ru(PPh3)3 (8) und nachfolgender Copolymerisation mit Si(OEt)4 zugänglich. 9c′, d′ und 10b′, c′ reagieren mit einem Äquivalent CO zu Cl2Ru(CO)()(P ∼ O) (12b′-d′). Mit überschüssigem CO erhält man die Spezies all-trans-Cl2Ru(CO)2(P ∼ O)2 (14b′-d′), die sich thermisch zu den cis,cis,trans-konfigurierten Isomeren 3b′-d′ umlagern. Ein Vergleich der Anisotropie der 31P-chemischen Verschiebung in kristallinem Cl2Ru()2 (9a, R = Ph, D = CH2OCH3) und Polysiloxan-gebundenem 9d′ deutet auf eine Beweglichkeit der Komplexe in der Matrix hin.
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  • 58
    ISSN: 0044-2313
    Keywords: Hydridorhodium complexes ; reactions with CO and methanol ; synthesis of a carbonyl(methyl)rhodium(I) complex ; protonation reactions ; intramolecular rearrangement ; nitrosylrhodium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Dynamic Behaviour of [Rh2(μ-H)3H2(PiPr3)4]+. Contributions to the Reactivity of the Tetrahydridodirhodium Complex [Rh2H4(PiPr3)4]An improved synthesis of [Rh2H4(PiPr3)4] (2) from [Rh(η3-C3H5)(PiPr3)2] (1) or [Rh(η3-CH2C6H5)(PiPr3)2] (3) and H2 is described. Compound 2 reacts with CO or CH3OH to give trans-[RhH(CO)(PiPr3)2] (4) and with ethene/acetone to yield a mixture of 4 and trans-[RhCH3(CO)(PiPr3)2] (5). The carbonyl(methyl) complex 5 has also been prepared from trans-[RhCl(CO)(PiPr3)2] (6) and CH3MgI. Whereas the reaction of 2 with two parts of CF3CO2H leads to [RhH2(η2-O2CCF3) · (PiPr3)2] (8), treatment of 2 with one equivalent of CF3CO2H in presence of NH4PF6 gives the dinuclear compound [Rh2H5(PiPr3)4]PF6 (9a). The reactions of 2 with HBF4 and [NO]BF4 afford the complexes [Rh2H5(PiPr3)4]BF4 (9b) and trans-[RhF(NO)(PiPr3)2]BF4 (11), respectively. In solution, the cation [Rh2(μ-H)3H2(PiPr3)4]+ of the compounds 9a and 9b undergoes an intramolecular rearrangement in which the bridging hydrido and the phosphane ligands are involved.
    Notes: Es wird über eine verbesserte Synthese von [Rh2H4(PiPr3)4] (2) aus [Rh(η3-C3H5)(PiPr3)2] (1) oder [Rh(η3CH2C6H5)(PiPr3)2] (3) und H2 berichtet. Verbindung 2 reagiert mit CO oder CH3OH zu trans-[RhH(CO)(PiPr3)2] (4) und mit Ethen/Aceton zu einem Gemisch von 4 und trans-[RhCH3(CO) · (PiPr3)2] (5). Der Carbonyl(methyl)-Komplex 5 ist ebenfalls aus trans-[RhCl(CO)(PiPr3)2] (6) und CH3MgI erhältlich. Während die Reaktion von 2 mit zwei Teilen CF3CO2H zu [RhH2(η2O2CCF3)(PiPr3)2] (8) führt, entsteht aus 2 und einem Äquivalent CF3CO2H in Gegenwart von NH4PF6 die zweikernige Verbindung [Rh2H5(PiPr3)4]PF6 (9a). Die Umsetzungen von 2 mit HBF4 und [NO]BF4 liefern die Komplexsalze [Rh2H5(PiPr3)4]BF4 (9b) und trans-[RhF(NO)(PiPr3)2]BF4 (11). Das in den Verbindungen 9a und 9b vorliegende Kation [Rh2(μ-H)3H2(PiPr3)4]+ unterliegt in Lösung einer intramolekularen Umlagerung, in der die verbrückenden Hydridoliganden und die Phosphangruppen einbezogen sind.
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  • 59
    ISSN: 0044-2313
    Keywords: Ternary Intermetallic Compounds ; Platinium ; Palladium ; Crystal Structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structures of the Compounds CaPtGa, CaPtIn and CaPd0.4Ga1.6The new compounds CaPtGa, CaPtIn and CaPd0.4Ga1.6 were prepared by heating appropriate mixtures of the elements under an Ar-atmosphere. The results of the structural analysis of single crystals by means of X-ray diffraction are given in the section „Inhaltsübersicht“. CaPtGa and CaPtIn are isotypic and form the TiNiSi type structure (Pnma), where the Pt-atoms have a distorted tetrahedral environment consisting of Ga- resp. In-atoms. CaPd0.4Ga1.6 crystallizes in the CeCu2-type structure (Imma), the Cu positions being statistically occupied by Pd- and Ga-atoms.
    Notes: Strukturuntersuchungen an den durch Erhitzen von Elementgemengen unter Argon hergestellten intermetallischen Verbindungen CaPtGa und CaPtIn zeigen, daß diese dem TiNiSi-Typ mit verzerrter Tetraederkoordination um die Pt-Atome entsprechen. Es liegt Raumgruppe Pnma (Nr. 62) mit den Gitterkonstanten für CaPtGa a = 7,184(1) Å, b = 4,429(1) Å, c = 7,595(1) Å und Z = 4 sowie für CaPtIn mit a = 7,280(1) Å, b = 4,372(1) Å, c = 8,356(1) Å und Z = 4 vor. Die Verbindung CaPd0,4Ga1,6 kristallisiert im CeCu2-Typ, bei der die Cu-Punktlagen statistisch von Ga- und Pd-Atomen besetzt sind. Die Strukturrechnung erfolgte in Imma (Nr. 72) mit a = 4,462(1) Å, b = 7,231(1) Å, c = 7,745(1) Å und Z = 4.
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  • 60
    ISSN: 0044-2313
    Keywords: Nickel and palladium boride colloids ; phosphine stabilization ; high resolution electron microscopy ; amorphous metal borides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ligandstabilisierte Nickel- und Palladiumborid-KolloideEs wird ein Weg zu den ersten ligand-stabilisierten Nickel- und Palladiumborid-Kolloiden mit Kerndurchmessern von 1,4 und 1,6 nm beschrieben. Die Teilchen bilden sich bei der Reaktion der Metallkomplexe Cl2M(PR3)2 (M = Ni, Pd; PR3 = PPr3, PBu3) mit B2H6 in Toluol bei Raumtemperatur in 40-70% Ausbeute. Die Charakterisierung der pyrophoren braunen Pulver erfolgte durch Elementaranalysen, die zu kleinsten Formeleinheiten führten, welche dann durch Molmassebestimmungen mittels analytischer Ultrazentrifuge zu gemittelten Molekülformeln erweitert werden konnten: [Ni6B10Cl1,5(PPr3)]12,5 (1), [Ni6B10Cl1,5(PBu3)]8,5 (2), [Pd4B6Cl(PPr3)]16,5 (3) und [Pd4B6Cl(PBu3)]16,5 (4). Aus den Massen der Kolloidkerne und ihren ungefähr berechneten Dichten konnte die Größe der Boridpartikel abgeschätzt werden. Die Durchmesser von 1,6 nm für 1, 3, und 4 sind innerhalb der Fehlergrenzen gleich. Nur 2 scheint einen geringfügig reduzierten Durchmesser von 1,4 nm zu besitzen. 1-4 können in inerten organischen Lösungsmitteln in beliebiger Konzentration dispergiert werden.Um diese relativ ungenauen Werte zu untermauern, wurde die hochauflösende Transmissionselektronenmikroskopie verwendet. Untersuchungen von 1 und 3 zeigen tatsächlich durchschnittliche Teilchengrößen von 1,6 ± 0,3 nm in Übereinstimmung mit den aus den Massebestimmungen erhaltenen Daten. Überraschenderweise scheinen die meisten der beobachteten Teilchen amorphe Struktur zu besitzen. Diese Beobachtung wird durch Röntgenbeugungsexperimente unterstützt, da keine signifikanten Reflexdaten erhalten werden konnten. 31P- und 11B-NMR-Messungen wurden ebenfalls vorgenommen, tragen jedoch zur weiteren Charakterisierung nicht bei.
    Notes: A route to the first ligand stabilized nickel and palladium boride colloids with core diameters of 1.4 and 1.6 nm is described. The particles are formed by reaction of the metal complexes Cl2M(PR3)2 (M = Ni, Pd, PR3 = PPr3, PBu3) with B2H6 in toluene at room temperature with 40-70% yield. The characterization of the pyrophoric brown powders occurred by elementary analyses, resulting in smallest formula units, which then could be extended to averaged molecular formulas by mass determinations, using an analytical ultracentrifuge: [Ni6B10Cl1.5(PPr3)]12.5 (1), [Ni6B10Cl1.5(PBu3)]8.5 (2), [Pd4B6Cl(PPr3)]16.5 (3), and [Pd4B6Cl(PBu3)]16.5 (4). From the masses of the colloid cores and their roughly calculated densities the size of the boride particles could be estimated. The diameters of 1.6 nm for 1, 3, and 4 are identical within the experimental error. Only 2 seems to have a slightly reduced diameter of 1.4 nm. 1-4 can be dispersed in inert organic solvents in any concentration.To confirm these relatively uncertain values high resolution transmission electron microscopy has been used. Investigations of 1 and 3 show indeed an averaged particle size of 1.6 ± 0.3 nm in agreement with the data derived from the mass determinations. Surprisingly most of the observed particles appear to have amorphous structure. This finding is supported by X-ray powder diffraction experiments, as no significant reflex data could be registered. 31P and 11B NMR measurements have been performed too, however, do not contribute to further characterization.
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  • 61
    ISSN: 0044-2313
    Keywords: Template Reaction ; Benzolhydrazido(2-)-acetylacetonebenzoylhydrazonato(2-)-oxomolybdenum(VI) ; Acetylacetonebenzoylhydrazone ; Mass Spectra ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Template Reaction of Bis(acetylacetonato)-dioxo-molybdenum(VI) with BenzoylhydrazoneBy reaction of bis(acetylacetonato)-dioxo-molybdenum(VI) with benzoylhydrazine benzoylhydrazido(2-)-acetylacetonebenzoylhydrazonato(2-)-oxo-molybdenum(VI) was formed beside another species. The compound was characterized by mass spectrometry and X-ray structural analysis. Crystallographic data see „Inhaltsübersicht“.
    Notes: Als Reaktionsprodukt der Umsetzung von Bis(acetylacetonato)-dioxo-molybdän(VI) mit Benzoylhydrazin in Gegenwart von Triphenylphosphan wurde Benzoylhydrazido-(2-)-acetylacetonbenzoylhydrazonato(2-)-oxo-molybdän(VI) neben einem weiteren Molybdänkomplex erhalten und massenspektrometrisch sowie röntgenkristallstrukturanalytisch charakterisiert. (Raumgruppe Cc, Z = 4, 2 020 beobachtete Reflexe, R = 3,7%. Gitterabmessungen bei 19°C: a = 1 188,5(2) pm, b = 2 110,2(2) pm, c = 813,2(2) pm, β = 105,77(2)°).
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  • 62
    ISSN: 0044-2313
    Keywords: Silicon Compounds ; Diaminosilylene ; Spirosilanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Silicon Compounds with Strong Intramolecular Steric Interactions. 54Mitteilung 53: K. Peters, E.-M. Peters, H. G. von Schnering, H. Piel, M. Weidenbruch, Z. Kristallogr., im Druck. . Attempted Generation of a Diaminosilylene: Formation of Spirosilanes and of Related CompoundsTreatment of the bulky substituted N,N′-bis(2,6-dimethylphenyl)ethylenediamine with n-butyllithium and subsequent cyclization with trichlorosilane or silicon tetrachloride gives the 2-chloro- and 2,2-dichloro-1,3-diaza-2-silacyclopentanes 3 and 4, respectively. Both compounds can easily be converted into the azido- (5) and diazidosilanes (6) and into the trisilane 7. Chlorine elimination from 4 in the presence of 2,3-dimethylbutadiene leads to the spirosilane 9 containing a nine-membered ring, whose structure was confirmed by X-ray crystallography. Reaction of 4 with lithium, followed by treatment with isopropanol gives beside other products the compound 10 consisting of two diazasilacyclopentane rings linked by a bridging ethylenediamino group. The X-ray structure determination of 10 shows that all six nitrogen atoms have a nearly planar environment. Upon photolysis, the azidosilane 5 provides the disiladispiro compound 12, presumably via a silanimine intermediate.
    Notes: Umsetzung von sperrig substituiertem N,N′-Bis(2,6-dimethylphenyl)ethylendiamin mit n-Butyllithium und nachfolgende Cyclisierung mit Trichlorsilan oder Siliciumtetrachlorid ergibt die 2-Chlor- und 2,2-Dichlor-1,3-diaza-2-silacyclopentan-Derivate 3 und 4. Beide Verbindungen können leicht in die Azido- (5) und Diazidosilane (6) sowie in das Trisilan 7 übergeführt werden. Die Chloreliminierung aus 4 in Gegenwart von 2,3-Dimethylbutadien liefert das Spirosilan 9 mit einem neungliedrigen Ring, dessen Aufbau durch die Röntgenstrukturanalyse gesichert ist. Umsetzung von 4 mit Lithium, gefolgt von der Einwirkung von Isopropanol führt neben anderen Produkten zu der Verbindung 10, in der zwei Diazasilacyclopentanringe durch eine Ethylendiaminbrücke miteinander verknüpft sind. Die Röntgenstrukturanalyse von 10 belegt die fast planare Umgebung aller sechs Stickstoffatome. Durch Photolyse von 5 wird vermutlich über ein intermediäres Silanimin die Disiladispiro-Verbindung 12 erhalten.