X-ray crystallographic and Mossbauer spectroscopic applications in dependence of partial quadrupole splitting, [R], on the C-Sn-C angle in seven-coordinated diorganotin(IV) complexes

The synthesis and the IR, NMR (H-1, C-13, and Sn-119), and Mossbauer spectroscopies and single-crystal X-ray diffraction studies of seven-coordinated diorganotin(IV) complexes, namely, [Ph2Sn(Hdapsc)]Cl center dot H2O center dot DMF [7; H(2)dapsc = 2,6-diacetylpyridine bis(semicarbazone)], [Me2Sn(H2,6Achexim)]Br center dot H2O [8; H(2)2,6Achexim = 2,6-diacetylpyridine bis(3-hexamethyleneiminylthiosemicarbazone)], [Me2Sn(dapmts)] [9; H(2)dapmts = 2,6-diacetylpyridine bis(4-methythiosemicarbazone)], and [(Bu2Sn)-Bu-n(dapmdtc)] [10; H(2)dapmdtc = 2,6-diacetylpyridine bis(S-methydithiocarbazate)], were done. The determination of the structures of [Ph2Sn(Hdapsc)](+), [Me2Sn(H2,6Achexim)](+) and [Me2Sn(dapmts)], [(Bu2Sn)-Bu-n(dapmdtc)] revealed the presence of monocationic and neutral complexes, respectively. The structures consist of monomeric units in which the Sn-IV ions exhibit distorted pentagonal-bipyramidal geometries, with the X, N,N,N,X-donor (X = O, S) systems of the ligands lying in the equatorial plane and the organic groups in the apical positions. The C-Sn-C angle in the seven-coordinated diorganotin( IV) complexes was estimated using a correlation between Mossbauer and X-ray data based on the point-charge model and using new values obtained in this work for [alkyl] = -1.00 mm s(-1) and [aryl] = -0.80 mm s(-1) for complexes containing O,N,N,N,O-pentadentate ligands and new values for [alkyl] = -0.87 mm s(-1) and [aryl] = -0.75 mm s(-1) for complexes containing S,N,N,N,S-pentadentate ligands.