Syntheses and characterisation of mercury complexes of sulfadiazine,sulfamerazine and sulfamethazine

The triple sulfa drugs, sulfadiazine, sulfamerazine and sulfamethazine, form a large number of metal complexes in different solvent media. The present studies show the synthesis and characterization of the Hg(II) complexes of sulfadiazine 1, sulfamerazine 2 and sulfamethazine 3 in dimethylformamide solution in presence of ammonia. The compounds were characterised by spectroscopic methods and crystal structures of the complexes were determined. All the compounds, 1, 2 and 3, crystallise in monoclinic crystal systems with the space groups of C2/c, C2/c and P2₁/c, respectively. Compounds 1 and 3 have eight coordinate ‘2+6’ geometries, with two tridentate sulfonamide ions and two DMF molecules in the coordination sphere. Complex 2 has a six co-ordinate, ‘2+4’ geometry which contains a short linear N–Hg–N moiety from co-ordinated sulfonamides. The IR spectral data suggest the binding of mercury atom to the sulfonamidic nitrogen atoms in agreement with the crystal structure determination.