CADMIUM(II) COMPLEXES OF 1,3-PROPANEDIAMINE WITH 2-THOURACIL AND ITS 6-METHYL DERIVATIVE

Four cadmium(ll) complexes containing four-membered N,S-chelates, [Cd( Htuc)(pn)(2)](+) and [Cd(tuc)(pn)(2)] (H(2)tuc = 2-thiouracil or 6-met hyl-2-thiouracil, pn = 1,3-propanediamine), have been prepared by reac ting Cd(pn)(2)Cl-2 with 2-thiouracil or its 6-methyl derivative in aqu eous methanol. The relative lowering of the (C=O) frequencies and the increase of the ring frequencies of the complexes compared to the free ligands have been assigned due to N(3) and S coordination. The downfi eld shift of the C-13 NMR signal due to the C(6) carbon atom of the co mplexes containing the tuc(2-) ligand compared to the complexes contai ning the Htuc(-) conclusively proves the chelation through its N(3) an d S donor atoms.