Cadmium(II) Complexes of 1, 3-Propanediamine with 2-Thiouracil and its 6-Methyl Derivative

Abstract

Four cadmium(II) complexes containing four-membered N,S-chelates, [Cd(Htuc)(pn)₂]⁺ and [Cd(tuc)(pn)₂] (H₂tuc = 2-thiouracil or 6-methyl-2-thiouracil, pn = 1,3-propanediamine), have been prepared by reacting Cd(pn)₂Cl₂ with 2-thiouracil or its 6-methyl derivative in aqueous methanol. The relative lowering of the (C[dbnd]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 downfield shift of the ¹³C NMR signal due to the C(6) carbon atom of the complexes containing the tuc^2- ligand compared to the complexes containing the Htuc conclusively proves the chelation through its N(3) and S donor atoms.