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  • 1
    ISSN: 0025-5874
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0044-2313
    Keywords: Transmetalation ; Calcium, Stannylene ; Tin ; Amide ; NMR Spectroscopy, X-Ray Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Substituted Calcium-bis(disilylamides) by Transmetalation of Tin(II) and Tin(IV) AmidesStannylenes as well as stannanes with substituted disilylamino groups are valuable synthons for the synthesis of alkaline earth metal bis(disilylamides) via the transmetallation reaction. Whereas bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentyl]stannylene 1 is a suitable reagent for this type of reaction, bis[trimethylsilyl-tris(trimethylsilyl)silylamino]stannylene 2 (monoclinic, P21/c, a = 1492.6(2), b = 1705.2(2), c = 1865.3(3) pm, β = 109.03(2)º, Z = 4) is not only attacked at the Sn—N-bond but also the N—Si-bond is cleaved by calcium metal. Similar light sensitivity as for 2 is observed for the mercury bis[trimethylsilyl-tris(trimethylsilyl)silylamide] 3, the homolytic M—N-bond cleavage leads to the formation of the trimethylsilyl-tris(trimethylsilyl)silylamino radical (g = 2.00485; a(N) = 16.2 G). The calcium tin exchange reaction of 1 in THF yields tris(tetrahydrofuran-O)calcium-bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentanide] 4 (monoclinic, P21/n, a = 1060.9(2), b = 1919.3(5), c = 1686.0(3) pm, β = 90.30(2)º, Z = 4). The stannanes Men-4Sn[N(SiMe3)2]n with n = 1 or 2 are also valuable materials for the synthesis of bis(tetrahydrofuran-O)calcium-bis[bis(trimethylsilyl)amide].
    Notes: Stannylene und Stannane mit substituierten Disilylamino-Substituenten eignen sich als Edukte für die Transmetallierungsreaktion zur Synthese von Calcium-bis(disilylamiden). Anwendung fanden Bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentyl]stannylen 1 und Bis[trimethylsilyl-tris(trimethylsilyl)silylamino]stannylen 2 (monoklin, P21/c, a = 1492,6(2), b = 1705,2(2), c = 1865,3(3) pm, β = 109,03(2)º, Z = 4). Bei der Verwendung von 2 greift das destillierte Calcium allerdings nicht nur die Sn - N-, sondern auch die N—Si-Bindung an. Ähnlich wie bei dem Quecksilber-bis[trimethylsilyl-tris(trimethylsilyl)silylamid] 3 beobachtet man bereits bei Tageslicht die homolytische Spaltung der Sn—N- bzw. Hg—N-Bindung und die Bildung des Trimethylsilyl-tris(trimethylsilyl)silylamino-Radikals 5 (g = 2,00485; a(N) = 16,2G). Der heterogen geführte Zinn-Calcium-Austausch bei Verbindung 1 in THF führt in guten Ausbeuten zum Tris(tetrahydrofuran-O)calcium-bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentanid] 4 (monoklin, P21/n, a = 1060,9(2), b = 1919,3(5), c = 1686,0(3) pm, β = 90,30(2)º, Z = 4). Auch die Stannane Men-4Sn[N(SiMe3)2]n mit n = 1 oder 2 eignen sich als Synthone zur Synthese von Bis(tetrahydrofuran-O)calcium-bis[bis(trimethylsilyl)amid].
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  • 3
    ISSN: 0044-2313
    Keywords: Barium 1-Aza-3-phosphapropenide ; 1,3-Azaphosphaallyl Anion ; NMR ; X-ray Structure Determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, NMR Spectroscopic Characterization and Structure of Bis(1,2-dimethoxyethane-O,O′)barium Bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenide]Barium-bis[bis(trimethylsilyl)phosphanide] 1 reacts with two equivalents of benzonitrile to give barium bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenide]; the choice of the solvent determines whether a tris-(tetrahydrofuran)- or a bis(1,2-dimethoxyethane)-complex 2 can be isolated. 2 crystallizes from DME as red cuboids (monoclinic, C2/c, a = 1627.0(3), b = 1836.6(3), c = 1602.5(2) pm; β = 96.071(12)°; V = 4761.7(12); Z = 4; wR2 = 0.0851). The phosphorus atom displays a pyramidal surrounding in contrast to the planar coordination sphere of the nitrogen atom. In addition a twist within the P—C—N skeleton of the heteroallyl anion is observed.
    Notes: Barium-bis[bis(trimethylsilyl)phosphanid] 1 reagiert mit zwei Äquivalenten Benzonitril zu Barium-bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenid]; durch die Wahl des Lösungsmittels läßt sich entweder der Tris(tetrahydrofuran)- oder der Bis(1,2-dimethoxyethan)-Komplex 2 isolieren. Verbindung 2 kristallisiert aus DME in Form roter Würfel aus (monoklin. C2/c, a = 1627,0(3), b = 1836,6(3), c = 1602,5(2) pm; β = 96,071(12)°; V = 4761,7(12); Z = 4; wR2 = 0,0851). Während die Koordinationssphäre des Stickstoffatoms planar ist, befindet sich das Phosphoratom in einer pyramidalen Umgebung. Zusätzlich beobachtet man im 1-Aza-3-phosphapropenid-Anion eine leichte Verdrillung.
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  • 4
    ISSN: 0570-0833
    Keywords: distannenes ; hypersily derivatives ; plumbylenes ; stannylenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 5
    ISSN: 1436-5081
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
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  • 6
    ISSN: 0044-2313
    Keywords: Yttrium complexes ; yttrium tris[bis(trimethylsilyl)amide] ; yttrium tris[bis(trimethylsilyl)methanide] ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bis(trimethylsilyl)amides and -methanides of Yttrium  -  Molecular Structures of Tris(diethylether-O)lithium-(μ-chloro)-tris[bis(trimethylsilyl)methyl]yttriate, solvent-free Yttrium Tris[bis(trimethylsilyl)amide] as well as the Bis(benzonitrile) ComplexThe reaction of yttrium(III) chloride with the three-fold molar amount of LiE(SiMe3)2 (E = N, CH) yields the corresponding yttrium derivatives. Yttrium tris-[bis(trimethylsilyl)amide] crystallizes in the space group P31c with a = 1 636,3(2), c = 849,3(2) pm, Z = 2. The yttrium atom is surrounded trigonal pyramidal by three nitrogen atoms with Y—N-bond lengths of 222 pm. Benzene molecules are incorporated parallel to the c-axes. The compound with E = CH crystallizes as a (Et2O)3LiCl-adduct in the monoclinic space group P21/n with a = 1 111,8(2), b = 1 865,2(6), c = 2 598,3(9) pm, β = 97,41(3)° and Z = 4. The reaction of yttrium tris[bis(trimethylsilyl)amide] with benzonitrile yields the bis(benzonitrile) complex, which crystallizes in the triclinic space group P1 with a = 1 173,7(2), b = 1 210,3(2), c = 1 912,4(3) pm, α = 94,37(1), β = 103,39(1), γ = 117,24(1)° and Z = 2. The amido ligands are in equatorial, the benzonitrile molecules in axial positions.
    Notes: Die Reaktion von Yttrium(III)-chlorid mit der dreifachen molaren Menge LiE(SiMe3)2 (E = N, CH) ergibt die entsprechenden Yttrium-Derivate. Yttrium-tris[bis(trimethylsilyl)amid] kristallisiert in der Raumgruppe P31c mit a = 1 636,3(2), c = 849,3(2) pm, Z = 2. Das Yttriumatom ist trigonal pyramidal koordiniert mit Y—N-Bindungslängen von 222 pm. Entlang der c-Achse sind Benzolmoleküle eingeschlossen. Die Verbindung mit E = CH kristallisiert als (Et2O)3LiCl-Addukt in der monoklinen Raumgruppe P21/n mit a = 1 111,8(2), b = 1 865,2(6), c = 2598,3(9) pm, β = 97,41(3)° und Z = 4. Die Umsetzung von Yttrium-tris[bis(trimethylsilyl)amid] mit Benzonitril ergibt einen Bis(benzonitril)-Komplex, der in der triklinen Raumgruppe P1 mit a = 1173,7(2), b = 1210,3(2), c = 1912,4(3) pm, α = 94,37(1), β = 103,39(1), γ = 117,24(1)° und Z = 2 kristallisiert. Die Amido-Liganden sind äquatorial, die Benzonitril-Moleküle axial koordiniert.
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  • 7
    ISSN: 0044-2313
    Keywords: Crystal Structure ; Electronic Structure ; Spectroscopic Data ; Tris(trimethylsilyl)phosphane Complexes ; Vanadium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Crystal Structure, Electronic Structure, Spectroscopic and Magnetic Properties of [VOCl2{P(SiMe3)3}2]: A Phosphane Complex with a Disordered VOCl2 GroupVOCl3 reacts with P(SiMe3)3 to form blue green crystals of [VOCl2{P(SiMe3)3}2] (1). The X-ray crystal structure analysis of 1 (cubic space group P213: a = 1541.4(1) pm, Z = 4) reveals a slightly distorded trigonal bipyramidal coordination environment for the disordered vanadium(IV) center. Density functional calculations on the compound [VOCl2{P(SiH3)3}2] (2) are in accord with this observation. 1 has been characterized by ESR, vibrational (IR and Raman) and electronic absorption spectroscopy and magnetic measurements. The ESR spectra of 1 in a toluene solution (293 K and frozen solution at 6 K) exhibit hyperfine interactions of the unpaired electron with the 51V center (I = 7/2) and the 31P centers (I = 1/2) of the two equivalent phosphane ligands. The ligand-field transitions of the VOCl2{P}2 chromophore observed in the electronic absorption spectrum have been assigned on the basis of density functional calculations on 2.
    Notes: Bei der Umsetzung von VOCl3 mit P(SiMe3)3 werden blaugrüne Kristalle von [VOCl2{P(SiMe3)3}2] (1) erhalten. Die Kristallstrukturanalyse von 1 (kubische Raumgruppe P213: a = 1541,4(1) pm; Z = 4) zeigt für das fehlgeordnete Vanadium(IV)-Zentrum eine leicht verzerrte, trigonalbipyramidale Umgebung, die durch Dichtefunktionalrechnungen an der Stammverbindung [VOCl2{P(SiH3)3}2] (2) bestätigt wird. Zur Charakterisierung von 1 wurden ESR-, Schwingungs- (IR und Raman) und Elektronenanregungsspektren aufgenommen und die magnetische Suszeptibilität bei Zimmertemperatur bestimmt. Die ESR-Spektren einer Lösung von 1 in Toluol (293 K und gefrorene Lösung bei 6 K) zeigen neben der Hyperfeinwechselwirkung des ungepaarten Elektrons mit dem 51V-Zentrum (I = 7/2) auch eine entsprechende Wechselwirkung mit den 31P-Zentren (I = 1/2) der beiden äquivalenten Phosphanliganden. Die Banden des VOCl2{P}2-Chromophors im Elektronenanregungsspektrum von 1 lassen sich mit Hilfe von Dichtefunktionalrechungen an 2 entsprechenden elektronischen Übergängen zuordnen.
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  • 8
    ISSN: 0044-2313
    Keywords: Phosphanide ; Calcium, Tin ; Bis(trimethylsilyl)phosphanide ; X-ray Structures ; Spectroscopic Data ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Trimethylsilyl Substituted Polyhedra of Calcium, Tin(II), and PhosphorusThe reaction of calcium-bis[bis(trimethylsilyl)amide] with bis(trimethylsilyl)phosphane in thf yields the heteroleptic, dimeric (tetrahydrofuran-O)calcium-bis(trimethylsilyl)amidebis(trimethylsilyl)phosphanide 1 (triclinic, P 1, a = 1066,6(2), b = 1141,3(2), c = 1226,6(2)pm, α = 97,78(3)°, β = 107,47(3)°, γ = 101,12(3)°, Z = 1 dimer). The bridging phosphanide-substituent displays with Ca—P bond lengths of 292,6 and 300,5 pm a distortion of the four-membered Ca2P2-cycle. The reaction with another equivalent of HP(SiMe3)2 in thf leads to the formation of tetrakis(tetrahydrofuran-O)calcium-bis[bis(trimethylsilyl)phosphanide] 2 mit Ca—P distances of 292 pm (monoclinic, P21/c, a = 1626,0(3), b = 1295,3(4), c = 2039,5(5) pm, β = 102,60(2)°, Z = 4). The performance of the reaction in the presence of bis[bis(trimethylsilyl)amino]stannylene yields heterobimetallic compounds with a central polyhedron of Ca-, Sn- and P-atoms. Dependent on the Sn/Ca ratio the isolation of tris(trimethylsilyl)phosphane as well as bis[tris(tetrahydrofuran-O)calcium]-ditin(II)-tetrakis(μ3-trimethylsilylphosphandiide) 3 with a central dicalcia-distanna-tetraphosphacubane-fragment or (thf)2CaSn2[μ-P(SiMe3)2]2[μ3-PSiMe3]2 4 (orthorhombic, Pnma, a = 2247,7(2), b = 1868,9(1), c = 1168,0(1) pm, Z = 4), respectively, succeeds. The Ca—P distances lie at 291 pm.
    Notes: Calcium-bis[bis(trimethylsilyl)amid] reagiert in THF mit Bis(trimethylsilyl)phosphan zu dem heteroleptischen, dimeren (Tetrahydrofuran-O)calcium-bis(trimethylsilyl)amid-bis(trimethylsilyl)phosphanid 1 (triklin, P 1, a = 1066,6(2), b = 1141,3(2), c = 1226,6(2) pm, α = 97,78(3)°, β = 107,47(3)°, γ = 101,12(3)°, Z = 1 Dimeres). Der verbrückend an zwei Calciumatome bindende Phosphanid-Substituent weist mit 292,6 und 300,5 pm sich deutlich unterscheidende Ca—P-Abstände auf. Die Umsetzung mit einem zweiten Äquivalent HP(SiMe3)2 führt in THF zur Bildung von Tetrakis(tetrahydrofuran-O)calcium-bis[bis(trimethylsilyl)phosphanid] 2 mit Ca—P-Bindungslängen von 292 pm (monoklin, P21/c, a = 1626,0(3), b = 1295,3(4), c = 2039,5(5) pm, β = 102,60(2)°, Z = 4). Setzt man Ca[N(SiMe3)2]2 in Anwesenheit von Bis[bis(trimethylsilyl)amino]stannylen mit Bis(trimethylsilyl)phosphan um, so isoliert man heterobimetallische Verbindungen mit einem Polyedergerüst aus Ca-, Sn- und P-Atomen. Je nach Sn/Ca-Verhältnis erhält man neben Tris(trimethylsilyl)phosphan Bis[tris(tetrahydrofuran-O)calcium]-dizinn(II)-tetrakis(μ3-trimethylsilylphosphandiid) 3 mit einem zentralen Dicalcia-distanna-tetraphosphacuban-Fragment oder (thf)2CaSn2[μ-P(SiMe3)2]2[μ3-PSiMe3]2 4 (orthorhombisch, Pnma, a = 2247,7(2), b = 1868,9(1), c = 1168,0(1) pm, Z = 4). Die Ca—P-Abstände bewegen sich um 291 pm.
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  • 9
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 10
    ISSN: 0044-8249
    Keywords: Distannene ; Hypersilyl-Derivate ; Plumbylene ; Stannylene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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