Probing the Kinetic Trans Effect in Halide Ion Substitution Reactions of Dinuclear Pt(III) Complexes Through Metadynamics Simulations

• Grant number: 24/00633-8
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Effective date (Start): May 01, 2024
• Effective date (End): October 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Lucas Colucci Ducati
• Grantee: Pedro Paulo Rezende Oliveira
• Supervisor: Barbara Kirchner
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: Universität Bonn, Germany
• Associated to the scholarship: 22/12004-0 - Ab Initio Investigation of the Solvent and Different Ligands on the 195Pt NMR Properties in Pt(III) Dinuclear Complexes, BP.MS

Abstract

Dinuclear Pt(III) complexes, characterized by a d7-d7 electronic configuration and octahedral coordination, hold significant potential in catalytic reactions and technological applications. Consequently, a comprehensive understanding of these complexes and their reactivity, particularly in solution, at the molecular level becomes imperative. Molecular dynamics (MD) simulations have emerged as a crucial tool for unraveling the thermodynamic and dynamic aspects of condensed systems at the molecular scale. However, conventional MD methods face limitations in capturing rare events, such as ligand dissociation and substitution reactions that are of interest in these complexes. To overcome these challenges, enhanced sampling techniques like metadynamics have gained prominence. In metadynamics, a bias potential is introduced inthe simulations, accelerating the exploration of the free-energy hypersurface along selectedcollective variables (CVs), overcoming the kinetic bottlenecks associated with traditional MDsimulations. Experimental investigations have explored axial-ligand substitution reactions in amidato-bridged Pt(III) dimers and have shown the involvement of a trans effect mediated through the Pt-Pt bond. While the trans effect has been extensively studied in Pt(II) complexes, its theoretical exploration in Pt(III) complexes where the effect traverses the metal-metal bond is notably underexplored. Considering explicit solvent inclusion to better comprehend solvation effects on electron density deformation, this research proposal focuses on the application of metadynamics to elucidate substitution reactions in amidato-bridged dinuclear Pt(III) complexes. The study aims to generate reaction paths through metadynamics simulations, permitting Energy Decomposition Analysis (EDA) and Natural Orbital for Chemical Valence (NOCV) analysis. These advanced analyses promise to offer greater insights into the nature of the trans effect in Pt(III) complexes, providing a comprehensive understanding of how trans ligands influence the free-energy barrier of ligands trans to themselves through the metal-metal bond.