engleski

Synthesis, Spectral and Thermal Characterization of Bis(pyridine-3- carboxy-2-thiolato-S)mercury(II). Crystal Structure of Dibromobis(3- metoxycarbonylpyridine-2-thiolato-S)mercury(II)

2-mercaptonicotinic acid (H_2mna = 2-HS(C_5H_3N)COOH) gave a thiolato compound of the formula Hg(Hmna)_2 by a reaction with various mercury(II) salts, HgX_2 (X = Cl^−, Br^−, I^−, SCN^−) in an ethanol or methanol solution irrespectively of the molar ratio of the reactants (1:1 or 1:2). The same compound was obtained from the reaction of mercury(II) acetate in an aqueous-ethanol solution. Hg(Hmna)_2 was characterized by vibrational spectroscopy and thermal analysis. 1^H and 13^C NMR measurements provided additional information on the thiol-thione tautomerism in H2mna and Hg(Hmna)_2 and also on the binding mode to mercury in the DMSO-d6 solution. HgBr_2(CH_3-Hmna)_2 was obtained from the reaction of H2mna with HgBr_2 in methanol after filtering off the main product Hg(Hmna)_2 (CH_3-Hmna = 2- HS(C_5H_3N)COOCH_3). The crystal structures of H2mna and HgBr_2(CH_3-Hmna)_2 were determined by the X-ray structure analysis. 2-mercaptonicotinic acid exists in the crystalline state in the thione tautomeric form. Two bromine atoms and two S-bound CH_3-Hmna ligands form a tetrahedral coordination sphere around the mercury atom in HgBr_2(CH_3-Hmna)_2.

2-mercaptonicotinic acid; mercury complex; thione-thiol tautomerism; X-ray single crystal; structure analysis; intra- and intermolecular hydrogen bonds; 1^H; 13^C NMR

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