Bis(pyrazolyl) palladium(II), platinum(II) and gold(III) complexes: Syntheses, molecular structures and substitution reactions with L-cysteine

A series of pyrazolyl palladium(II), platinum(II) and gold(III) complexes, [PdCl2(3,5-R(2)bpza)] {R = H (1), R = Me (2), bpza = bis-pyrazolyl acetic acid}, [PtCl2(3,5-R(2)bpza)] {R = H (3a), R = Me (4)}, [AuCl2(3,5-R(2)bpza)] Cl {R = H (5a), R = Me (6a)} and [PdCl2(3,5-R(2)bpzate)] {R = Me (7)} have been synthesised and structurally characterised. Single crystal X-ray crystallography showed that the pyrazolyl ligands exhibit N boolean AND N-coordination with the metals. Anticancer activities of six complexes 1-6a were investigated against CHO cells and were found to have low activities. Substitution reactions of selected complexes 1, 2, 3a and 5a with L-cysteine show that the low anticancer activities compounds and that the rate of substitution with sulfur-containing compounds is not the cause of the low anticancer activities. (C) 2008 Elsevier B.V. All rights reserved.