A Comparative Assessment of the Effect of the Lewis Acidity of the Central Tin Atom on Intramolecular Coordination of (3‐Methoxypropyl)stannanes

Autor: Petra Zoufalá, Tomas Lebl, Clemens Bruhn
Rok vydání: 2005
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2005:2536-2544
ISSN: 1099-0682
1434-1948
DOI: 10.1002/ejic.200400877
Popis: The recently studied set of (3-methoxypropyl)stannanes of general formula R x SnCl 4 - x [R = (CH 2 ) 3 OCH 3 , x = 4 (1), x = 3 (2), x = 2 (3) and x = 1 (4)] is extended with two new sets of (3-methoxypropyl)stannanes of general formula RPh 3 - x SnCl x [x = 0 (5), x = 1 (6) and x = 2 (7)] and RSn(S 2 CNEt 2 ) 3 - x Cl x [x = 0 (8), x = 1 (9) and x = 2 (10)]. The molecular structures of 6, 7, 9 and 10 in the solid state were determined by X-ray diffraction. In compounds 6 and 7, the 3-methoxypropyl ligand forms a C,O-chelate and the tin atom is coordinated as a distorted trigonal bipyramid with the oxygen and one chlorine atom in the axial positions. Compounds 9 and 10 are hexacoordinate with a distorted octahedral ligand arrangement. While the 3-methoxypropyl ligand in 10 also forms a C,O-chelate, the oxygen atom in 9 is not coordinated to the central tin atom. The structures in a non-coordinating (CDCl 3 ) and a coordinating solvent ([D 6 ]DMSO) were studied by multinuclear 1 H, 1 3 C and 1 1 9 Sn NMR spectroscopy. It is proposed that the structures found in the solid state are retained upon dissolution in CDCl 3 . Compounds 5, 8 and 9 also preserve their structures in [D 6 ]DMSO. On the other hand, an equilibrium, in which one or more molecules of solvent enter the coordination sphere of the central tin atom and cleave the oxastannacycle, is established in [D 6 ]DMSO solutions of 6, 7 and 10. A comparison of the J 1 H, 1 1 9 Sn coupling constants obtained from 1D 1 H, 1 1 9 Sn HMQC and 2D 1 H, 1 1 9 Sn J-HMBC spectra and the J 1 3 C, 1 1 9 Sn coupling constants derived from conventional 1D 1 3 C NMR spectra shows that the best indicator of the O→Sn donor-acceptor interaction in 3-methoxypropylstannanes is the 3 J 1 3 C 1 1 9 Sn value.
Databáze: OpenAIRE
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