The reaction of the ligands H2dapf and H2dapt, with R4-mSnXm (m = 2, 3; R = Me, Ph and X = Cl, Br) led to the formation of eight new heptacoordinated organotin(IV) complexes, which were studied by microanalysis, IR, NMR and Mössbauer spectroscopy to investigate their structural properties. The methyl derivative [Me2Sn(Hdapt)]Br.H2O was also studied by single crystal X-ray diffraction. It crystallizes in the monoclinic system, space group P2(1)/c, with a = 21.920(3), b = 7.4470(5), c = 16.805(2) Å, beta = 110.18(1)º, Z = 4. The structure determination revealed a monocationic complex of Sn(IV) in a distorted bipyramidal geometry [Me2Sn(Hdapf)]+, with Br- as counter ion and one molecule of water helping the crystal packing. Mössbauer parameters of the complex [Me2Sn(Hdapf)]2[Me2SnCl4] have evidenced two Sn(IV) sites, as observed in the crystal structure determination. Also a correlation between Mössbauer and X-ray data based on the point-charge model is discussed.
hydrazone complexes; heptacoordinated organotin(IV) complexes
