Abstract

A series of Pt(ll) complexes with antitumor properties: [1,2-bis(2,6-dichloro-4-hydroxyphenyl)ethylenediamine]PtL2 (meso-1-PtL2) and [erythro-1-(2,6-dichloro-4-hydroxyphenyl)-2-(2-halo-4-hydroxyphenyl)ethylenediamine]PtL2, [2L=2Cl−,2I−,SO42−; halo = F (erythro-8-PtL2), halo = Cl (erythro-9-PtL2)] has been modelled by molecular mechanics (MM). The MM calculations were carried out for different isomers and ligand conformations meso-δ, meso-λ, d,l-δ, d,I-λ. The compounds with the lowest MM energies have the same geometries as those obtained by X-ray analysis. The calculated MMX energy orders: meso-1-PtL2 < erythro-9-PtL2 < erythro-8-PtL2 for L=I−, Cl− and SO42− are reverse to the known antitumor activity order - the lowest energy complex (the most stable one)is the one with the highest estrogen activity (meso-1-PtL2). The type of the leaving group (L) does not alter the energy order, which is in agreement with the biological experiments that show a slight dependence of the estrogen properties on the leaving group type.