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 a nd IR spectroscopy in the solid state, and by one- and two-dimensional H-1 and C-13 NMR spectroscopy in the dimethylsulfoxide solution. The X-ray crys tallographic analysis of the two polymorphic forms of Hg(SCN)(2)(C5H5NS)(2) (1a and 1b) showed that the mercury atom is coordinated by four sulfur ato ms farming a distorted octahedron. The Hg-S distances an in the range from 2.458(1) to 2.512(1) Angstrom. IR data of the complex Hg(SCN)(C5H4NCOO)(C5H 4NCOOH) (2a) showed presence of dissociated and undissociated picolinic aci d. Hg(C5H4NCOO)(2) (2b) was obtained by dissolving 2a in dimethylsulfoxide. NMR characterization of this compound showed that mercury is coordinated b y two oxygen atoms from picolinate ions. (C) 1999 Elsevier Science S.A. All rights reserved.