Homobimetallic Au(I)-Au(I) and Heterotrimetallic Au(I)-Fe(II)-Au(I) Complexes with Dialkyldithiophosphates and Phosphine Ligands: Structural Characterization, DFT Analysis, and Tyrosinase Inhibitory and Biological Effects

The role of bridging and terminal ligand electronic andstericproperties on the structure and antiproliferative activity of two-coordinatedgold-(I) complexes was investigated on seven novel binuclear and trinucleargold-(I) complexes synthesized by the reaction of either Au-2(dppm)-Cl-2, Au-2(dppe)-Cl-2, or Au-2(dppf)-Cl-2 with potassium diisopropyldithiophosphate,K-[(S-O (i) Pr)(2)], potassium dicyclohexyldithiophosphate,K-[(S-OCy)(2)], or sodium bis-(methimazolyl)-borate, Na-(S-Mt)(2), which afforded air-stable gold-(I) complexes. In 1-7, the gold-(I) centers adopt a two-coordinatedlinear geometry and are structurally similar. However, their structuralfeatures and antiproliferative properties highly depend upon subtleligand substituent changes. All complexes were validated by H-1, C-13-{H-1}, P-31 NMR, and IR spectroscopy.The solid-state structures of 1, 2, 3, 6, and 7 were confirmed usingsingle-crystal X-ray diffraction. A density functional theory geometryoptimization calculation was used to extract further structural andelectronic information. To investigate the possible cytotoxicitiesof 2, 3, and 7, in vitro cellulartests were carried out on the human cancerous breast cell line MCF-7. 2 and 7 show promising cytotoxicity.

Automated summary

The impact of ligand electronic and steric properties on the structure and antiproliferative activity of gold-(I) complexes was studied. Seven novel binuclear and trinuclear gold-(I) complexes were synthesized and their properties were analyzed. The cytotoxicity of two complexes, 2 and 7, showed promising results.