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  • 1
    ISSN: 0044-2313
    Keywords: Titanium-Aluminium Alkoxide ; Aluminium Titanate (Tialite) ; Ceramics Precursor ; X-Ray Structure Determination ; 1H/13C-NMR (2 D) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structural Characterization of a Novel Titanium-Aluminium AlkoxideThe novel Ti-Al-Alkoxide TiAl2(OiPr)10, was synthesized from aluminium turnings and titanium tetraisopropoxide in 2-propanol and isolated by subsequent fractionating distillation. Colourless prismatic crystals precipitated after 24 h at 20°C from the main fraction. They proved very moisture sensitive. The compound crystallizes in the monoclinc space group C2/c (no. 15) with a = 2303.1(4), b = 1097.2(3), c = 1685.0(3) pm, β = 104.32(1)° and Z = 4. The molecular structure exhibits a bent Al-Ti-Al′ unit, in which Al shows tetrahedral, but Ti octahedral1 coordination. The polyhedra are connected via cis-edges of the octahedron. The structure of the compound in solution was determined by NMR spectroscopy (1H, 13C, COSY) and proved to be identical to the structure in the solid state.
    Notes: Das neue Ti-Al-Alkoxid TiAl2(OiPr)10 wurde durch Umsetzung von Al-Spänen mit Titantetraisopropoxid in Isopropanol und anschließender fraktionierender Destillation dargestellt. Die nach 24 h bei 20°C aus der Hauptfraktion gebildeten farblosen, prismatischen Kristalle sind sehr hydrolyseempfindlich. Die Kristallstruktur konnte bei -83°C bestimmt werden: monokline Raumgruppe C2/c (Nr. 15) mit a = 2303,1(4), b = 1097,2(3), c = 1685,0(3) pm, β = 104,32(1)° und Z = 4. Die Molekülstruktur besteht aus einer gewinkelten Al-Ti-Al′-Einheit, in der Al tetraedrisch und Ti oktaedrisch koordiniert sind. Die verknüpfenden Kanten am Ti-Oktaeder sind cis angeordnet. Die Struktur der Verbindung in Lösung wurde NMR-spektroskopisch (1H, 13C, COSY) ermittelt und stimmt mit der Struktur im Einkristall überein.
    Additional Material: 1 Ill.
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  • 2
    ISSN: 0009-2940
    Keywords: cis-Stannyl-boryl-alkenes ; Sulfur diimide anions ; Multinuclear NMR ; 1,2,5-Azastannaboratoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 1,2,5-Azastannaborole Derivatives from Sulfur Diimide Anions and cis-Stannyl-boryl-alkenes - X-ray Crystallographic Study of Two 2,5-Dihydro-1-(imino-λ4-sulfanylidene)-1,2,5-azastannaboratoles(E)-3-(Diethylboryl)-2-(chlorodimethylstannyl)-2-pentene (1) reacts with the sulfur diimide anions 3 [R - NSN-K+, R=tBu (a), Me3Si (b), tBu2P (c)] in a 1:1 ratio, and with 4 (K+;-NSN-K+) in a 2:1 ratio, to give various heterocycles. The first products of the reaction between 1 and 3 [2,5-dihydro-1-(imino-λ4-sulfanylidene)-1,2,5-azastannaboratoles 5a, b, c] are isolated at -30°C and characterized by X-ray crystallography. The compounds 5a,b rearrange into the borole derivates 6a,b (with an additional N—Sn coordination) by transfer of an ethyl group from the boron to the sulfur atom. Ethylene is eliminated from compound 6a (not 6b) to give the diaminosulfane derivative 7a. The 2:1 reaction between 1 and 4 affords an unstable intermediate 8 with a fluxional structure, leading to 9 in which an EtS moiety bridges a borole ring (analogous to 6 but without the additional N - Sn coordination) and a boratole ring (analogous to 5). All compounds are characterized by 1H-, 11B-, 13C-, 15N- (in part), 29Si- and 119Sn-NMR spectra.
    Additional Material: 2 Ill.
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