Syntheses, structural and spectral studies of six-coordinate, [Ph2SnCl(acpm)], and seven-coordinate, [nBu2Sn(dapm)], diorganotin(IV) complexes with N,N,S-tridentate and S,N,N,N,S-pentadentate N4-heterocyclic thiosemicarbazones

The reaction of the N,N,S-tridentate ligand 2-acetylpyridine (N4-morpholyl thiosemicarbazones), Hacpm, with Ph2SnCl2 leads to the formation of the six-coordinate complex [Ph2SnCl(acpm)] (1), whereas the reaction of the S,N,N,N,S-pentadentate ligand 2,6-diacetylpyridine bis(N4-morpholyl thiosemicarbazone), H2dapm, with nBu2SnCl2 leads to the formation of the seven-coordinate complex [nBu2Sn(dapm)] (2). Both compounds were studied by microanalyses, IR, NMR (1H, 13C, 119Sn) and Mössbauer spectroscopy to investigate their structural properties. The organotin(IV) complexes were also studied by single crystal X-ray diffraction and the structure determination revealed that the phenyl derivative crystallizes in the triclinic space group (P1¯) as discrete neutral molecules, with the tin(IV) ion in a distorted octahedral geometry with the acpm1− ligand in a meridional configuration and the phenyl groups in trans positions. X-ray analysis shows that the n-butyl complex crystallizes in the monoclinic space group (P21/c) as discrete neutral complexes, with the tin(IV) ion in a distorted pentagonal bipyramidal geometry. A correlation between Mössbauer and X-ray data based on the point-charge model is discussed.