Pt-M Complexes (M=Ag, Au) as Models for Intermediates in Transmetalation Processes

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Exploration of heteropolynuclear complexes with unique bonding arrangements.
• Understanding metal-metal interactions in polynuclear structures.

Purpose of the Study:

• Synthesize and characterize novel platinum-metal heteropolynuclear complexes.
• Investigate the structural, spectroscopic, and electronic properties of these complexes.
• Elucidate the nature of Pt-M bonds and associated dynamic processes.

Main Methods:

• Synthesis of heteropolynuclear complexes [(CNC)(PPh3)PtM(PPh3)]ClO4 and [{Pt(CNC)(PPh3)}2M]ClO4 (M=Au, Ag).
• X-ray crystallography to determine solid-state structures.
• Spectroscopic techniques (NMR) for solution-state analysis.
• Density Functional Theory (DFT) calculations for electronic structure and bonding analysis.

Main Results:

• Confirmed the formation of Pt-M bonds and M⋅⋅⋅Cipso interactions in the solid state.
• NMR studies revealed persistent Pt-M interactions and an intramolecular dynamic process in solution.
• DFT calculations identified key orbital interactions governing the Pt-M bonding, with stronger interactions for gold complexes.

Conclusions:

• The synthesized complexes display significant Pt-M interactions, stronger in gold analogues than silver.
• An arrested transmetalation process is proposed, where Pt-M interactions represent an intermediate stage.
• The polydentate CNC ligand prevents further ligand exchange, stabilizing these intermediate structures.