Synthesis and characterization of heptacoordinated tin(IV) complexes. X-ray crystal structure of [nBu2Sn(dappt)]·(Me 2CO)0.5 [H2dappt = 2,6-diacetylpyridine bis(4-phenylthiosemicarbazone)]

The reactions of the 2,6-diacetylpyridine bis(4-phenylthiosemicarbazone) ligand, H2dappt, with R4-mSnXm (m = 2, 3; R = Me, nBu, Ph and X = Cl) led to the formation of four new heptacoordinated organotin(IV) complexes, which were characterized by microanalyses and by IR and M ssbauer spectroscopies. The n-butyl derivative [nBu2Sn(dappt)]·(Me 2CO)0.5 was also analyzed by a single crystal X-ray diffraction study. It crystallized in the monoclinic system with a space group C2/c, with a = 36.164(14), b = 9.7050(15), c = 26.194(11) , beta = 132.00(2)o, Z = 8. The structure determination revealed a neutral complex of Sn(IV) in a distorted pentagonal bipyramidal (PBP) geometry, with the equatorial plane defined by the SNNNS donor system of the ligand and with the two n-butyl groups in the axial positions. Also, a correlation between M ssbauer and X-ray data based on the point-charge model is discussed.