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 and steric properties on the structure and antiproliferative activity of two-coordinated gold(I) complexes was investigated on seven novel binuclear and trinuclear gold(I) complexes synthesized by the reaction of either Au(dppm)Cl, Au(dppe)Cl, or Au(dppf)Cl with potassium diisopropyldithiophosphate, K[(S-OPr)], potassium dicyclohexyldithiophosphate, K[(S-OCy)], or sodium bis(methimazolyl)borate, Na(S-Mt), which afforded air-stable gold(I) complexes. In -, the gold(I) centers adopt a two-coordinated linear geometry and are structurally similar. However, their structural features and antiproliferative properties highly depend upon subtle ligand substituent changes. All complexes were validated by H, C{H}, P NMR, and IR spectroscopy. The solid-state structures of , , , , and were confirmed using single-crystal X-ray diffraction. A density functional theory geometry optimization calculation was used to extract further structural and electronic information. To investigate the possible cytotoxicities of , , and , in vitro cellular tests were carried out on the human cancerous breast cell line MCF-7. and show promising cytotoxicity.