engleski

Mercury(II) complexes of heterocyclic thiones. Part 1. Preparation of 1:2 complexes of mercury(II) halides and pseudohalides with 3, 4, 5, 6-tetrahydropyrimidine-2-thione. X-ray, thermal analysis and NMR studies

A series of complexes HgX_2(H_4pymtH)_2 (X = Cl, Br, I, SCN, CN ; H_4pymtH = 3, 4, 5, 6-tetrahydropyrimidine-2-thione) has been obtained by the reaction of H_4pymtH with mercury(II) halides and pseudohalides in the 2:1 molar ratio. X-ray diffraction studies revealed tetrahedral coordination of mercury with S-bound H4pymtH. The exception is Hg(CN)_2(H_4pymtH)_2 where the coordination is 2+2 with two strongly bound CN� {; ; ; ; ; ligands and weaker Hg� {; ; ; ; ; S bonds with H4pymtH. One- and twodimensional 1^H and 13^C NMR measurements in dimethylsulfoxide solution confirmed the complexation of mercury to sulphur. The greatest complexation effects on chemical shifts were detected for the C-2, C-5 and H-1, 3 atoms i.e. two, four and five bonds away from mercury atom. The complexation effects in Hg(SCN)_2(H_4pymtH)_2 and Hg(CN)_2(H_4pymtH)_2 are in agreement with the strongest intramolecular H-bonding in the former and the weakest Hg-S bonds in the latter as compared to other complexes here.

crystal structures; thermal analysis; mercury complexes; heterocyclic thione complexes; NMR studies

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