H-1, C-13, N-15, CD-113, 2D N-15-H-1 AND SOLID-STATE C-13 CP/MAS NMR OF HG AND CD COMPLEXES OF 4(1H)-QUINAZOLINONE-2,3-DIHYDRO-2-THIOXO

The Cd(II) and Hg(II) complexes of 4(1H)-quinazolinone-2,3-dihydro-2-thioxo (1) and the free ligand were studied by 1D and 2D multinuclear magnetic resonance in solution and C-13 cross polarization magic angle spinning NMR in the solid state. Compound 1 adopts only one of five possible tautomeric structures in solution, namely the thiouracyl-like structure. It was found that the metal atom is linked to two molecules of deprotonated 1 by N-1 and coordinated by the sulphur atom. The compounds retain the same structure in the solid state and in dimethyl sulphoxide solution.