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 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-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 1 H, 13 C{ 1 H}, 31 P NMR, and IR spectroscopy. The solid-state structures of 1 , 2 , 3 , 6 , and 7 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 2 , 3 , and 7 , in vitro cellular tests were carried out on the human cancerous breast cell line MCF-7. 2 and 7 show promising cytotoxicity.