The synthesis, structure and lewis acidity of bidentate organotin alkanes and carboxylates
Abstract
A series of bis(diphenylbromostannyl)alkanes of the type (C H ) BrSn(CH ) SnBr(C H ) , where n = 6, 10 and 12, and a series of bis(tributylstannyl)carboxylates of the type (n-C H ) SnO C(CH ) CO Sn(n-C H )3, where n = 2, 6, 10, 12 and 14, were prepared. Tin-119 solid state NMR of the carboxylates indicated that the compounds contain five-coordinate, structurally-equivalent tins in the solid state. Adduct formation with triethylphosphine oxide (TEPO) for both the alkanes and carboxylates was monitored by phosphorus-31 NMR. Equilibrium constants for the alkanes were approximately independent of chain length from n = 6 to 12, while for the carboxylates, the constants for n = 2 and n = 14 were small. Equilibrium constants for the intermediate chains were approximately the same. Solid state NMR shows that the 1:1 TEPO adduct of the n = 12 carboxylate contains two different tin atoms, both of which are five-coordinate, and that the adduct is probably not symmetrically chelated. © 1995, Walter de Gruyter. All rights reserved. 6 5 2 2 n 6 5 2 4 9 3 2 2 n 2 4 9