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-dimet hylpyrimidine-2-thiol (4,6Me(2)Pm2SH) forms a multinuclear complex wit h mercury, containing an open HgN3S2 core and exhibiting a helix-like polymerization through repetitive distant Hg(sp(3)d)...N(sp(2)) intera ctions along the b axis of the lattice. The complex, therefore, exempl ifies a supramolecular assembly, generated by successive vacant ligand site promoted self-associations. It crystallizes in the monoclinic sp ace group P2(1)/c, a = 11.808(2), b = 9.198(2), and c = 14.702(3) Angs trom, beta = 112.19(3)degrees, Z = 4 (monomers). Such self-associative distant interactions are absent in solution phase, as observed from t he H-1 NMR spectrum (acetone-d(6), TMS). A preliminary toxicological s tudy of the pyrimidinethiol ligand reveals a high toxicity at substant ially higher does and appreciably low toxic effects at lower doses. Th e ligand is also highly potent in inhibiting all common gram negative bacteria (except the acid fast group, which was not tested) and this p roperty may endow it with some side therapeutic uses when considered a s an antidote to mercury poisoning following some functional modificat ions in order to reduce the toxic effects, even when administered at h igher doses. (C) 1997 Elsevier Science Inc.