Spectral and structural studies of mercury(II) complexes of 2- pyridineformamide N(4)-dimethylthiosemicarbazone

AbstractReaction of 2-pyridineformamide N(4)-dimethylthiosemicarbazone (HAm4DM) with halides of mercury(II) directly affordedcomplexes of the form [Hg(HAm4DM)X 2 ](X / Cl, Br or I). In all these new compounds, which were characterized by elementalanalysis, IR spectroscopy and 1 H, 13 C, and, when possible, 199 Hg NMR spectroscopy, the ligand coordinates through its sulfur atomand pyridine and azomethine nitrogen atoms, as was confirmed by X-ray diffraction studies in the case of [Hg(HAm4DM)Br 2 ] / DMSO. Ethanolic solutions of [Hg(Am4DM)Cl 2 ] and [Hg(Am4DM)Br 2 ] afforded crystals of [Hg(Am4DM)Cl] 2 and[Hg(Am4DM)Br] 2 , the structures of which were also studied by single-crystal X-ray diffractometry. In these two compounds theanionic ligand, Am4DM , coordinates to one Hg through pyridine nitrogen, imine nitrogen and thiolato sulfur atoms, the last ofwhich bridges to the other Hg via a bond that is shorter than the chelating Hg / S bond. Thus all three of the complexes studied by X-ray diffractometry have pentacoordinated Hg centre and in all three cases the coordination polyhedron is closer to a square pyramidthan to a trigonal bipyramid.# 2003 Elsevier Science Ltd. All rights reserved.