The crystal and molecular structure of(HgL(2))(n) (L=4,6-dimethylpyrimidine-2-thiolate) - An unusual helical supramolecular assembly in solid phase: In search of a new antidote to mercury poisoning

An X-ray crystallographic study reveals that in solid phase, 4,6-dimethylpyrimidine-2-thiol (4,6Me(2)Pm2SH) forms a multinuclear complex with mercury, containing an open HgN3S2 core and exhibiting a helix-like polymerization through repetitive distant Hg(sp(3)d)...N(sp(2)) interactions along the b axis of the lattice. The complex, therefore, exemplifies a supramolecular assembly, generated by successive vacant ligand site promoted self-associations. It crystallizes in the monoclinic space group P2(1)/c, a = 11.808(2), b = 9.198(2), and c = 14.702(3) Angstrom, beta = 112.19(3)degrees, Z = 4 (monomers). Such self-associative distant interactions are absent in solution phase, as observed from the H-1 NMR spectrum (acetone-d(6), TMS). A preliminary toxicological study of the pyrimidinethiol ligand reveals a high toxicity at substantially higher does and appreciably low toxic effects at lower doses. The ligand is also highly potent in inhibiting all common gram negative bacteria (except the acid fast group, which was not tested) and this property may endow it with some side therapeutic uses when considered as an antidote to mercury poisoning following some functional modifications in order to reduce the toxic effects, even when administered at higher doses. (C) 1997 Elsevier Science Inc.