Synthesis and Antitumour Activity of Gold(I) and Silver(I) Complexes of Hydrazine-Bridged Diphosphine Ligands

Abstract

A known synthetic route was used to prepare two known hydrazine-bridged phosphine ligands and four new ligands with variable groups on the hydrazine bridge (methyl and ethyl), as well as positions on the aryl phosphine groups (phenyl, methoxyphenyl, dimethylaminophenyl). A range of gold(I) and silver(I) complexes were synthesized utilizing these phosphine ligands. Both the phosphine-bridged dimetal and cationic bis(diphosphine) metal complexes were isolated. An interesting phenomenon of the spontaneous oxidation of gold(I) to gold(III) (and reduction of gold(IIII) to gold(I)) upon complexation with ((N,N-dimethyl)-4-aminophenyl)dialkylhydrazine ligands is described. Thirteen of the synthesized complexes were subjected to anticancer activity screening against HeLa, Jurkat, A2780, cisplatin-resistant A2780, CoLo 320 DM and MCF7. Most of the complexes were found to inhibit the cancerous cells at low μM concentrations and in some cases nM concentrations. Two of the complexes were tested for their ability to reduce the mitochondrial membrane potential ofPBMCcells as a possible mechanism of action of anticancer activity.

Keywords: Gold(I), silver(I), hydrazine, diphosphine, antitumour, anticancer, mitochondrial membrane potential