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Preparation and spectroscopic properties of the complexes of mercuric thiocyanate with pyridine-2-thione and pyridine-2-carboxylic acid. Crystal and molecular structure of two polymorphs of Hg(SCN)(2)(C5H5NS)(2)

Complexes of pyridine-2-thione and pyridine-2-carboxylic acid with mercury(II) thiocyanate have been prepared and characterized by chemical analysis and IR spectroscopy in the solid state and by one- or two-dimensional 1H and 13C NMR spectroscopy in the dimethylsulfoxide solution. The X-ray crystallographic analysis of the two polymorphic forms of Hg(SCN)_2(C_5H_5NS)_2 (1a and 1b) showed that the mercury atom is coordinated by four sulfur atoms forming a distorted tetrahedron. The Hg-S distances are in the range from 2.458(1) to 2.512(1) A. IR data of the complex Hg(SCN)(C_5H_4NCOO)(C_5H_4NCOOH) (2a) showed presence of dissociated and undissociated picolinic acid. Hg(C_5H_4NCOO)_2 (2b) was obtained by dissolving 2a in dimethylsulfoxide. NMR characterization of this compound showed that mercury is coordinated by two oxygen atoms from picolinate ions.

Crystal structures; Mercury complexes; Thiocyanate complexes

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