Crystal structure and molecular structure of trans-dichloro-, trans-dimethyl, trans-bis(quinoline N-oxide)tin

Dimethyltin dichloride forms with quinoline N-oxide a stereochemically crowded all-trans-octahedral 1/2 molecular complex that crystallizes in the monoclinic P21/n space group (a = 10.022(1) Å, b = 10.4374(8) Å, c = 10.871(2) Å; β = 116.674(6)°). Anisotropic refinement of non-hydrogen and isotropic refinement of hydrogen atoms converged to R = 0.018 for 1537 independent I ≥ 3σ(I) reflections.

Structural and spectral studies of N-(3-hydroxypyridine-2-yl)salicylideneimine and N-(3-hydroxypyridine-2-yl)-5-bromosalicylideneimine and their dimethyltin(IV) complexes

N-(3-hydroxypyridine-2-yl)salicylidineimine (1), N-(3-hydroxypyridine-2-yl)-5-bromo salicylideneimine (2) and their diorganotin(IV) complexes formulated as Me2Sn(OC6H4CH=NC5H3NO) (3) and Me2Sn(OC6H3BrCH=NC5H3NO) (4) were prepared and characterized by 1H-NMR, IR, mass spectroscopy and single crystal x-ray diffraction study. The crystal structures of 3 [orthorhombic, Pbna (no 60); a = 10.439(1) Å, b = 13.388(3) Å, c = 19.340(2) Å, Z = 4; V = 2703(1) Å3] and 4 [monoclinic, P21/a (no 14); a = 7.528(4) Å, b = 16.576(7) Å, c = 12.017(7) Å, β = 97.97(5), Z = 4; V = 1485(1) Å3] have been solved by standard methods and refined by full-matrix least squares (carried out on F 2) to R values of 0.066 and 0.046 respectively. The studied tin(IV) complexes (3 and 4) exhibit the distorted trigonal-bipyramidal geometries around Sn atoms, separately. The tautomeric effects of ligands and the substitution of Br atom to the common molecular structure were discussed beside of the coordination geometries of 3 and 4.

Zinnhalogenverbindungen. III. Neuere Daten zur Kristall- und Molekülstruktur von Dimethylzinndichlorid, Me2SnCl2

The crystal structure of dimethyltin dichloride, Me2SnCl2, known for a long time, has been corrected by means of four-circle diffractometer data, because in comparison to other diorganotin dichlorides serious doubts about the molecular geometry came up. The new, corrected values confirm the old structure model but supply more reliable data in view of the molecular parameters. In particular, the following values have been found for distances and angles: d(Sn-C) = 212.0(7) pm, d(Sn-Cl) = 238.9(2) pm, ∠(Cl-Sn-Cl) = 98.60(9)°, ∠(C-Sn-C) = 142.2(4)°. The length of the intermolecular tin···chlorine bridge was determined to 343.3 pm. This value shows that dimethyltin dichloride has a strong intermolecular association due to small sterical shielding of the tin atom by the methyl groups.

Síntese e caracterização de compostos diorganoestânicos com ácido dl-mandélico

Por reação de quantidades eqüimoleculares de R2SnO ou R2SnCl2 (R = -CH3; -C4H9) com ácido dl-mandélico, C6H5CH(OH)COOH, em meio de etanol, foram obtidos novos compostos formulados como [(LR2Sn)2O] [L= C6H5CH(OH)COO-], nos quais o átomo de estanho é pentacoordenado, com o ligante L estabelecendo uma ligação bidentada através dos átomos de oxigênio dos grupos ácido e hidroxila alcoólica. Nas mesmas condições, nenhum produto obtido a partir da reação de (C6H5)2SnO ou (C6H5)2SnCl2 pode ser identificado. No entanto, quando da reação de (C6H5)2SnCl2 com ácido dl-mandélico, em meio de acetonitrila, foi preparado um composto dimérico hexacoordenado formulado como [L(C6H5)2SnCl]2. Este composto não pode ser isolado de forma pura e está misturado com 7% de impurezas não identificadas, cujos parâmetros de interação hiperfina sugerem tratar de estanho tetravalente octaedricamente coordenado por oxigênio. Os compostos obtidos foram caracterizados por determinação de ponto de fusão, microanálise e espectroscopias i.v. e Mössbauer.