Preference of di-n-butyltinIV compounds to build O•••Sn bonds in fused rings with five-six members

The reaction of salicylaldehyde (1), o-aminophenols (2a-2f), and di-n-butyltin(IV) oxide (3) to give six di-n-butyltin(IV) compounds (4a-4f) was achieved in good yields. All compounds were characterized by H-1, C-13, N-15, Sn-119 NMR, mass spectrometry, IR, elemental analysis and in the case of compounds 4a, 4b, 4d and 4e by X-ray diffraction analysis. Compound 4a crystallized with trigonal bipiramidal (TPB) geometry surrounding the tin atom while 4b and 4e crystallized as dimeric molecules joined by two (OSn)-Sn-... bonds with distorted octahedron (DOC) geometry. The X-ray structure of 4d presents one cocrystallized monomeric TBP with one dimeric DOC molecule. Correlations of sigma(Hammett) vs. spectroscopic values were found for 4a-4b and 4d-4f, indicating the substituents in the aromatic ring derived from o-aminophenol serve as modulators of the (OSn)-Sn-... supramolecular interaction. The (OSn)-Sn-... bond formation is selective for the five-membered ring oxygen atom. (C) 2004 Elsevier B.V. All rights reserved.