Molecular structures of organotin tropolonato complexes with tin coordination numbers 5-7, seen by single-crystal X-ray diffraction and solid- and solution-state 119Sn NMR

Organotin tropolonato complexes of the type R3Sn(trop) 1 [R = Bu (b), Ph (c),] R2Sn(trop)(2) 2 [R = Me (a), Bu (b), Ph (c)] and RSn(trop)(3) 3 [R = Bu (b), Ph (c)] were studied by single-crystal X-ray diffraction (1c, 2a, b, 3b), C-13 and Sn-119 MAS NMR and Sn-119 NMR in solution. The tin coordination numbers from 5 to 7, as determined for the solid state, are retained in solution. The different distorted octahedral surroundings (cis-like arrangement of the methyl groups in 2a; trans-like arrangement of the butyl groups and weak intermolecular association in 2b) of the tin atoms in solid compounds 2 are reflected both by the Sn-119 chemical shift anisotropies and the magnitude of the coupling constants \(1)/(Sn-117/119,C-13)\. The molecular structures of 2a and 2b become more similar to each other in solution, as indicated by differences in the isotropic Sn-119 chemical shifts in solution and in the solid state, and even more obvious by changes in the magnitude of the corresponding coupling constants \(1)/(Sn-117/119,C-13)\. Copyright (C) 2001 John Wiley Sons, Ltd.