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  • Organic Chemistry  (9)
  • Crystal Structures  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Synthese und Konformationsanalyse von Pyranophanonen und Pyrylophanium-Verbindungen mit intraannularen Substituenten (1993)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 335 (1993), S. 503-514 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Conformational Analysis of Pyranophanones and Pyrylophanium Compounds with Intraannular SubstituentsThe synthesis of [3.3]dithiapyranophanone 6 and 11 is accomplished by use of the two-components-dilution-principle. Pyrolysis of their bis(sulfones) 7 and 12 gives the [2.2]pyranophanones 8, 9 and 13. Under preservation of conformation the intraannular carbonyl-function is used for the synthesis of methylpyranophanoles 14, 16 and 17. The synthesis of pyrylophanium compounds 15 and 18 is possible by elimination in trifluoroacetic acid.6 exhibits anti-conformation within its crystal-structure and like 7 reveals temperature-dependent behavior in solution. Using 6 as an example, a combination of 13C-NMR-spectroscopy, forcefield-calculation and computer-simulation is applied for the first time to give evidence for molecular-dynamic processes of cyclophanes.8 and 9 are the syn- and anti-conformers of the desired product, as shown by X-ray structural analysis. 13 reveals anti-conformation within its crystal structure as well as in solution. The conformational analysis of other new phanes described here is based on the 1H-NMR-spectra of these pyrolysis products.As expected the intraannular substituents of Pyrylophanium-lons 15 and 18 show the characteristic upfield-shift within their 1H-NMR-spectra.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19933350603
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  • 2
    Electronic Resource
    Electronic Resource
    Reactions of 3,5-Diaryl-1,2-dithiolium Salts and 3,5-Diaryl-1,2,4-dithiazolium Salts with Metal Cyclopentadienides (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 221-228 
    Details
    ISSN: 0947-3440
    Keywords: 3,5-Diaryl-1,2-dithiolium salts ; 3,5-Diaryl-1,2,4-dithiazolium salts ; Metal cyclopentadienides ; 3,7-Dithiatricyclo[4.4.0.02,8]deca-4,9-diene ; 3,5-Dithiatricyclo[4.2.2.02,6]deca-7,9-diene ; 3,7-Dithia-5-azatricyclo[4.4.0.02,8]deca-4,9-diene ; Diels-Alder reactions ; Nitrogen heterocycles ; Sulfur heterocycles ; Polycycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of the 3,5-diaryl-1,2-dithiolium salts 2 with the metal cyclopentadienides 4 and 9 leads to the formation of the tricyclic compounds 6 and 10 via a ring-opened intermediate, which undergoes an intramolecular Diels-Alder cyclization. Compounds 6 and 10 rearrange by treatment with boron trifluoride-diethyl ether to the isomeric compounds 7 and 11. The structures 6f and 7f were confirmed by X-ray analysis. Condensation of the 3,5-diaryl-1,2,4-dithiazolium salts 3 with the metal cyclopentadienides 4 affords the tricyclic compounds 12, which do not rearrange by Lewis acid catalysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970133
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  • 3
    Electronic Resource
    Electronic Resource
    Positional and Facial Selectivity in Diels-Alder Reactions of (-)-(aS,7S)-Colchicine: Synthesis of Novel Analogues of the Alkaloid (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 851-857 
    Details
    ISSN: 0947-3440
    Keywords: Colchicine, diene properties of ; Positional selectivity ; Stabilized exciplex through hydrogen bonding ; π-Facial diastereoselectivity ; Photooxygenation ; Solvent effects ; Cycloadditions ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positional and facial selectivity in Diels-Alder reactions of several hetero- and carbodienophiles with (-)-(aS,7S)-colchicine (1) has been examined. In all cases, cycloaddition occurred with high positional selectivity at the 8,12-positions of the alkaloid and preferentially from the diene face syn to the allylic substituent at the stereogenic center C-7. The observed high π-facial diastereoselectivity is independent of the polarity of the solvent used and is therefore probably a consequence of steric factors. The structures of the Diels Alder-adducts of 1 with singlet oxygen, N-phenyl-1,2,4-triazolinedione (PTAD) and trans-cyclooctene, 4,5, and 15, respectively, were assigned on the basis of spectral data and verified by X-ray crystallography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970510
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesen mit aliphatischen Dialdehyden, XLII. (2,4,6-Cycloheptatrien-1-yliden)malonaldehyd (8,8-Diformylheptafulven)  -  Herstellung, Struktur und Reaktionen (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1997-2011 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XLII.  -  (2,4,6-Cycloheptatrien-1-ylidene)malonaldehyde (8,8-Diformylheptafulvene)  -  Synthesis, Structure, and Reactions8,8-Diformylheptafulvene (5) was synthesized for the first time by hydride abstraction from sodium salts of(cycloheptatrienyl)malonaldehydes (2 and 3). In solution, 5 exists in a solventdependent equilibrium with its valence isomer 6. The structure of 5 was determined by means of its 1H and 13C NMR spectrum, dipole moment (5.24 D), and an X-ray analysis; its dipole moment and chemical reactivity were also estimated by MNDO calculations.  -  Reactions of 5 with electrophiles (→7) and with nucleophiles (→ 8 - 14 are described.
    Notes: 8,8-Diformylheptafulven (5) wurde zum ersten Mal hergestellt durch Hydridabstraktion aus (Cycloheptatrienyl)malonaldehyd-Natriumsalzen (2 und 3). 5 steht in Lösung mit dem Valenzisomeren 6 in einem lösungsmittelabhängigen Gleichgewicht. Die Struktur von 5 wurde durch 1H- und 13C-NMR-Spektrum, Dipolmoment (5.24 D) sowie eine Röntgenstrukturanalyse gesichert; Dipolmoment und chemische Reaktivität wurden auch durch MNDO-Berechnungen abgeschätzt. - Reaktionen von 5 mit Elektrophilen (→7) und mit Nucleophilen (→8 - 14) werden beschrieben.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519851008
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesen mit aliphatischen Dialdehyden, XL. (2,4,6-Cycloheptatrien-1-yl)malonaldehyd - Herstellung, Struktur und Reaktionen (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1969-1986 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XL. - (2,4,6-Cycloheptatrien-1-yl)malonaldehyde - Synthesis, Structure, and ReactionsTropylation of the sodium salt of malonaldehyde with cycloheptatrienylium tetrafluoroborate yielded the enolized, s-trans-configurated (2,4,6-cycloheptatrien-1-yl)malonaldehyde (1) for the first time. Reaction of 1 with anilines leads to the 3-anilino-2-propenals 3 and 4 with Fischer's base to the pentamethine cyanine dye 5, with maleic anhydride and tetracyanoethylene to the cycloadducts 6 and 7, and with bifunctional N-nucleophiles to the cycloheptatrienyl-substituted heterocycles 10 - 12. The structures of 3 and 5 were determined by means of X-ray analyses.
    Notes: Tropylierung des Malonaldehyd-Natriumsalzes mit Cycloheptatrienylium-tetrafluoroborat ergab erstmals den enolisierten, s-trans-konfigurierten (2,4,6-Cycloheptatrien-1-yl)malonaldehyd (1). Umsetzungen von 1 mit Anilinen führen zu den 3-Anilino-2-propenalen 3 und 4, mit dem Fischerbase-Quartärsalz zum Pentamethincyanin-Farbstoff 5, mit Maleinsäureanhydrid und Tetracyanethylen zu den Cycloaddukten 6 und 7, und mit bifunktionellen N-Nucleophilen zu den cycloheptatrienlylsubstituierten Heterocyclen 10 - 12. Die Struktur von 3 und 5 wurde röntgenographisch ermittelt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519851006
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  • 6
    Electronic Resource
    Electronic Resource
    Die Kristallstrukturen von (NH4)2[ReCl6], [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN und [ReCl4(18-Krone-6)] (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 525-530 
    Details
    ISSN: 0044-2313
    Keywords: Rhenium Complexes ; Syntheses ; IR spectra ; Crystal Structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structures of (NH4)2[ReCl6], [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN and [ReCl4(18)(Crown-6)]Brown single crystals of (NH4)2[ReCl6] are formed by the reaction of NH4Cl with ReCl5 in a suspension of diethylether. [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN crystallizes as brown crystal plates from a solution of ReCl5 in acetonitrile. Lustrous green single crystals of [ReCl4(18-crown-6)] are obtained by the reaction of 18-crown-6 with ReCl5 in a dichloromethane suspension. All rhenium compounds are characterized by IR spectroscopy and by crystal structure determinations.(NH4)2[ReCl6]: Space group Fm3m, Z = 4, 75 observed unique reflections, R = 0.01. Lattice constant at -70°C: a = 989.0(1) pm. The compound crystallizes in the (NH4)2[PtCl6] type, the Re—Cl distance is 235.5(1) pm.[ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN: Space group P1, Z = 1, 2459 observed unique reflections, R = 0.12. Lattice dimensions at -60°C: a = 859.0(1), b = 974.2(7), c = 1287.3(7) pm, α = 102.69(5)°, b̃ = 105.24(7)°, γ = 102.25(8)°. The structure consists of two symmetry-independent [ReCl2(CH3CN)4]+ ions with trans chlorine atoms, [ReCl6]2- ions, and included acetonitrile molecules. In the cations the Re—Cl bond lengths are 233 pm in average, in the anion they are 235 pm in average.[ReCl4(18-crown-6)]: Space group P21/n, Z = 4, 3 633 observed unique reflections, R = 0.06. Lattice dimensions at -70°C: a = 1040.2(4), b = 1794.7(5), c = 1090.0(5) pm, b̃ = 108.91(4)°. The compound forms a molecular structure, in which the rhenium atom is octahedrally coordinated by the four chlorine atoms and by two oxygen atoms of the crown ether molecule.
    Notes: Braune Einkristalle von (NH4)2[ReCl6] entstehen durch Reaktion von NH4Cl mit ReCl5 in einer Diethylethersuspension. [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN kristallisiert als braune Kristallplättchen aus einer Lösung von ReCl5 in Acetonitril. Leuchtend grüne Einkristalle von [ReCl4(18-Krone-6)] entstehen durch Reaktion von 18-Krone-6 mit ReCl5 in einer Dichlormethansuspension. Die drei Rhenium-Verbindungen werden durch ihre IR-Spektren und durch Kristallstrukturanalysen charakterisiert.(NH4)2[ReCl6]: Raumgruppe Fm3m, Z = 4, 75 unabhängige beobachtete Reflexe, R = 0,01. Gitterkonstante bei -70°C: a = 989,0(1) pm. Die Verbindung kristallisiert im (NH4)2[PtCl6]-Typ, der Re—Cl-Abstand beträgt 235,5(1) pm.[ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN: Raumgruppe P1, Z = 1, 2459 beobachtete unabhängige Reflexe, R = 0,12. Gitterkonstanten bei -60°C: a = 859,0(1); b = 974,2(7); c = 1287,3(7) pm, α = 102,69(5)°; b̃ = 105,24(7)°; γ = 102,25(8)°. Die Struktur besteht aus zwei symmetrieunabhängigen [ReCl2(CH3CN)4]+-Ionen mit trans-ständigen Chloratomen, [ReCl6]2--Ionen und eingelagerten Acetonitrilmolekülen. In den Kationen betragen die Re—Cl-Abstände im Mittel 233 pm, im Anion im Mittel 235 pm.[ReCl4(18-Krone-6)]: Raumgruppe P21/n, Z = 4, 3 633 beobachtete unabhängige Reflexe, R = 0,06. Gitterkonstanten bei -70°C: a = 1040,2(4); b = 1794,7(5); c = 1090,0(5) pm; b̃ = 108,91(4)°. Die Verbindung bildet eine Molekülstruktur, in der das Rheniumatom oktaedrisch von den vier Chloratomen und von zwei Sauerstoffatomen des Kronenethers koordiniert ist.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210404
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  • 7
    Electronic Resource
    Electronic Resource
    Reaktionen von MoNCl3 und WNCl3 mit elementarem Fluor. Kristallstrukturen von [MoO2F2(THF)2] und [WF4(NCl)(CH3CN)] (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 1195-1199 
    Details
    ISSN: 0044-2313
    Keywords: Tetrafluoro-N-chloro-Imido Complexes of Molybdenum and Tungsten ; Donor-Acceptor Complexes ; Crystal Structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of MoNCl3 and WNCl3 with Elemental Fluorine. Crystal Structures of [MoO2F2(THF)2] and [WF4(NCl)(CH3CN)]The nitrido chlorides MoNCl3 and WNCl3 as well as WCl4(NCl) react with elemental fluorine forming the N-chloro imido complexes MoF4(NCl) and WF4(NCl), which were characterized by IR spectroscopy. With tetrahydrofurane MoF4(NCl) reacts to give [MoF4(NCl)(THF)], which in THF solution slowly converts into [MoO2F2(THF)2]. From WF4(NCl) with acetonitrile the complex [WF4(NCl)(CH3CN)] is obtained. Both donor acceptor complexes were characterized by crystal structure determinations.[MoO2F2(THF)2]: Space group P21/n, Z = 4, structure solution with 1823 unique reflections, R = 0.033 for reflections with I 〉 2σ(I). Lattice dimensions at -40°C: a = 636.2, b = 1119.5, c = 1625.2 pm; β = 93.92(1)º. The compound has a monomeric molecular structure with the fluorine atoms in trans-position to one another and with the oxygen atoms of the THF molecules in trans to the oxo ligands.[WF4(NCl)(CH3CN)]: Space group P21/m, Z = 2, structure solution with 1119 unique reflections, R = 0.038 for reflections with I 〉 2σ(I). Lattice dimensions at 20°C: a = 511.7, b = 714.9, c = 1002.5 pm; β = 102.59(10)º. The compound has a monomeric molecular structure in which the nitrogen atom of the acetonitrile molecule coordinates in trans-position to the N-chloro imido group W≡N—Cl. The structural parameters of this group are WN = 172.2 pm, NCl = 161.1 pm, WNCl = 178.6º.
    Notes: Die Nitridochloride MoNCl3 und WNCl3 reagieren ebenso wie WCl4(NCl) mit elementarem Fluor unter Bildung der N-chlorimido-Komplexe MoF4(NCl) und WF4(NCl), die durch ihre Spektren charakterisiert werden. Mit Tetrahydrofuran reagiert MoF4(NCl) unter Bildung von [MoF4(NCl)(THF)], das sich in THF-Lösung langsam in MoO2F2(THF)2 umwandelt. WF4(NCl) bildet mit Acetonitril den Komplex [WF4(NCl)(CH3CN)]. Von beiden Donor-Akzeptor-Komplexen wurden Kristallstrukturanalysen angefertigt.[MoO2F2(THF)2]: Raumgruppe P21/n, Z = 4, Strukturlösung mit 1823 unabhängigen Reflexen, R = 0,033 für Reflexe mit I 〉 2σ(I). Gitterkonstanten bei -40°C: a = 636,2; b = 1119,5; c = 1625,2 pm; β = 93,92(1)º. Die Verbindung hat eine monomere Molekülstruktur, in der die F-Atome in trans-Position zueinander und die O-Atome der THF-Moleküle in trans-Stellung zu den Oxoliganden angeordnet sind.[WF4(NCl)(CH3CN)]: Raumgruppe P21/m, Z = 2, Strukturlösung mit 1119 unabhängigen Reflexen, R = 0,038 für Reflexe mit I 〉 2σ(I). Gitterkonstanten bei 20°C: a = 511,7; b = 714,9; c = 1002,5 pm; β = 102,59(10)º. Die Verbindung hat eine monomere Molekülstruktur, in der das N-Atom des Acetonitrilmoleküls in trans-Stellung zur N-chlorimido-Gruppe W≡N—Cl angeordnet ist. Die Strukturparameter dieser Gruppe sind WN = 172,2 pm, NCl = 161,1 pm, WNCl 178,6º.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220715
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  • 8
    Electronic Resource
    Electronic Resource
    A Novel Cycloocta[d]-/Barreleno[d]pyridazine RearrangementDedicated to Prof. Dr. Dr. h.c. F. Eiden on the occasion of his 70th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 661-666 
    Details
    ISSN: 0947-3440
    Keywords: Cyclooctatetraene-bicyclooctatriene valence tautomerism ; [4+2] Cycloadditions, inverse ; Cycloocta[d]pyridazine ⇛ barreleno[d]pyridazine rearrangement ; [1, 3]-Carbon migration ; Catalysis, 1,3-tautomerization with 2-hydroxypyridine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As part of the valence tautomeric system cyclooctatetraene (2) bicyclo[4.2.0]octa-2,4,7-triene (3), the monocyclic polyene (2) reacts as a dienophile with the diazadiene 3,6-bis(trifluoromethyl)-1,2,4,5-tetrazine (1) to form after N2-elimination two products: The 1 : 1-adduct 6, a cycloocta[d]pyridazine, and the tetracyclic bis-Diels-Alder cycloadduct 9. Depending on solvent polarity and temperature, compound 6 displays interesting novel rearrangements. On refluxing in nonpolar solvents like toluene, compound 6 yields the barreleno[d]pyridazine 13 in high yield. Compound 13 can be oxidized with 4-phenyltriazolinedione 14 to the barreleno[d]pyridazine 15. When the more polar nitromethane is used as a solvent, heating of 6 at 90° 2°C surprisingly leads to the dihydrocycloocta[d]pyridazine 18 in a multistep reaction including proton-shift tautomerism and [1, 5]-sigmatropic rearrangement. The structures of the compounds 15 and 18 were assigned by the spectral data and verified by X-ray crystallography.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950493
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  • 9
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    Electronic Resource
    Diels-Alder Reactions of (1H-Indol-3-yl)-enacetamides and -endiacetamides: A Selective Access to Acetylamino-Functionalized [b]Annelated Indoles and CarbazolesThis work is dedicated to Prof. Dr. Dr. Ernst Mutschler, Frankfurt/Main, on the occasion of his 60th birth day. (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 727-738 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diels-Alder reactions of the (1H-indol-3-yl)-enacetamides and -endiacetamides 1a-d with some carbodieno-philes and 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione give rise to the novel amino-functionalized carbazole; 4-6 and 8 (Scheme 3). Ethenetetracarbonitrile reacts with 1b to furnish the Michael-type adduct 7 (Scheme 3). Structural aspects of the starting materials 1, which exhibit above all 3-vinyl-1H-indole reactivity, are discussed with regard to the prediction of a Diels-Alder process.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740406
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  • 10
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    Electronic Resource
    Funktionalisierte Alkinkomplexe von Wolfram(VI). Synthese und Kristallstrukturen von [WCl4(Et—Se—C≡C—Se—Et)(THF)] und [WCl4(Et—Te—C≡C—Te—Et)(THF)]Professor Gerhard Fritz zum 75. Geburtstag gewidmet (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 388-392 
    Details
    ISSN: 0044-2313
    Keywords: Functionalized Alkyne Complexes of Tungsten ; Synthesis ; IR spectra ; Crystal Structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Functionalized Alkyne Complexes of Tungsten(VI). Syntheses and Crystal Structures of [WCl4(Et—Se—C≡C—Se—Et)(THF)] and [WCl4(Et—Te—C≡C—Te—Et)(THF)]The title compounds have been prepared by reactions of [WCl4(SEt2)2] with the alkynes Et—X—C≡C—X—Et (X = Se, Te) in CCl4 solution and subsequent addition of tetrahydrofurane. Both complexes were characterized by crystal structure determinations.[WCl4(Et—Se—C≡C—Se—Et)(THF)]: Space group P21/n, Z = 4, structure determination with 2942 unique reflections, R = 0.038. Lattice dimensions at 20°C: a = 934.2, b = 1639.5, c = 1189.5 pm, β = 96.497°.[WCl4(Et—Te—C≡C—Te—Et)(THF)]: Space group P21/n, Z = 4, structure determination with 4097 unique reflections, R = 0.067, Lattice dimensions at -70°C: a = 899.2, b = 1691.9, c = 1213.3 pm, β = 96.82°.The complexes have monomeric molecular structures with the oxygen atom of the THF molecules in trans-position to the side-on bound alkyne ligands.
    Notes: Die Titelverbindungen werden aus [WCl4(SEt2)2] und den Alkinen Et—X—C≡C—X—Et (X = Se, Te) in CCl4-Lösung nach Zusatz von Tetrahydrofuran erhalten und durch Kristallstrukturanalysen charakterisiert.[WCl4(Et—Se—C≡C—Se—Et)(THF)]: Raumgruppe P21/n, Z = 4, Strukturverfeinerung mit 2942 unabhängigen Reflexen, R = 0,038. Gitterabmessungen bei 20°C: a = 934,2; b = 1639,5; c = 1189,5 pm, β = 96,497°.[WCl4(Et—Te—C≡C—Te—Et)(THF)]: Raumgruppe P21/n, Z = 4, Strukturverfeinerung mit 4097 unabhängigen Reflexen, R = 0,067. Gitterabmessungen bei -70°C: a = 899,2; b = 1691,9; c = 1213,3 pm, β = 96,82°.Beide Verbindungen haben monomere Molekülstrukturen, in denen sich das O-Atom des THF-Moleküls in trans-Position zum seitlich gebundenen Alkinliganden befindet.
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    URL: http://dx.doi.org/10.1002/zaac.19956210308
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