Force-modulated reductive elimination from platinum(ii) diaryl complexes

Area of Science:

• Organometallic Chemistry
• Mechanochemistry
• Computational Chemistry

Background:

• Mechanical forces are known to influence covalent chemical reactions.
• The impact of force on spectator ligands in transition metal reactivity remains largely uninvestigated.

Purpose of the Study:

• To quantify the effect of mechanical force on spectator ligands on the rate of reductive elimination in platinum(II) complexes.
• To explore the relationship between ligand structure, applied force, and reaction kinetics.

Main Methods:

• Density Functional Theory (DFT) computations to model mechanochemical kinetics.
• Experimental validation using platinum(II) diaryl complexes with macrocyclic bis(phosphine) ligands.
• Utilized a macrocyclic force probe ligand coupled to a MeOBiphep-based design.

Main Results:

• Complex dependence of mechanochemical kinetics on ligand structure was revealed by DFT.
• Compressive forces decreased reductive elimination rates, while extension forces increased them (3.4-fold change over ~290 pN).
• Force primarily affects the transition state's O⋯O distance, not the ground state geometry of the platinum complex.

Conclusions:

• Mechanical force applied to spectator ligands can significantly modulate transition metal reactivity.
• Demonstrated a method to experimentally map force-induced geometric changes in reaction transition states.
• Highlights potential for force-modulated catalysis and understanding reaction mechanisms.