Binuclear platinum-iridium complexes: synthesis, reactivity and luminescence

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Heterobinuclear platinum-iridium complexes offer unique electronic and structural properties.
• The ligand bis(diphenylphosphino)methane (dppm) is crucial for stabilizing dinuclear metal centers.
• Understanding the reactivity of such complexes is key to developing new catalytic and photophysical materials.

Purpose of the Study:

• To investigate the chemical behavior of the heterobinuclear platinum-iridium complex [PtIr(CO)3(μ-dppm)2][PF6].
• To explore reactions with hydrides, dihydrogen, hydrogen chloride, silanes, and alkynes.
• To characterize the resulting complexes and their properties, including fluxional behavior and luminescence.

Main Methods:

• Synthesis and characterization of the platinum-iridium complex [PtIr(CO)3(μ-dppm)2][PF6].
• Reactions with various chemical agents including hydrides, H2, HCl, Ph2MeSiH, and substituted alkynes.
• Spectroscopic analysis (NMR, IR) and structural determination of reaction products.

Main Results:

• Reaction with hydride displaced a carbonyl ligand from platinum.
• Oxidative addition at iridium occurred with dihydrogen, HCl, and Ph2MeSiH, yielding fluxional complexes.
• Regioselective formation of μ-η(1),η(1) bridging alkyne complexes with various alkynes.
• Reversible CO insertion and subsequent reactions of alkyne complexes with HCl and H2 were observed.
• The complex [PtIr(μ-HCCPh)(CO)2(μ-dppm)2][PF6] displayed intense room-temperature luminescence.

Conclusions:

• The heterobinuclear platinum-iridium complex exhibits diverse reactivity, allowing for the synthesis of novel organometallic structures.
• The observed fluxionality and regioselectivity highlight the intricate coordination chemistry at the Pt-Ir interface.
• The luminescent properties of the bridging alkyne complex suggest potential applications in photochemistry and materials science.