Stability of metal-metal interactions in transmetallation intermediates based on electronics of bridging arene ligands determined through pyridine titrations.

In this contribution, we prepare the dinuclear complex [(CNC)(PPh)Pt-Au(PPh)] (2-F) supported by an electron deficient derivative of 2,6-diphenylpyridine (CNC), 2,6-di(4-fluorophenyl)pyridine (CNC). Solution state spectroscopic data and solid-state structural data reveals formation of the desired dinuclear complex occurs and that it remains intact in solution. The solid state structure of 2-F, compared to [(CNC)(PPh)Pt-Au(PPh)] (2), reveals a substantial change in the C-Au-P bond angle. We postulated that this change in bond angle arises due to a weaker interaction between [(PPh)Au] and (CNC)Pt(PPh) (1-F) . (CNC)Pt(PPh) (1). Through pyridine titration experiments, we demonstrate that the interaction is indeed weaker between [(PPh)Au] and 1-F. 1. Cyclic voltammetry (CV) experiments confirm that 1-F is less electron rich than 1. DFT calculations demonstrate that the HOMO of 1 and 1-F is not d, helping explain the differences in electrochemical behavior of 1 and 1-F and bonding between 1 and 1-F with [(PPh)Au].