Computational Investigations of Transition Metal Based Catalyzed Organic Transformations

Abstract

Chapter one provides a comprehensive overview of transition metal complexes, with a focus on the catalytic roles of iron complexes in reaction mechanisms, particularly oxidation reactions mediated by Fe(IV)O species, including non-heme variants. It reviews relevant literature on biologically inspired enzymes and biomimetic complexes, discussing key concepts like Two-State Reactivity and electron/proton transfer mechanisms. The chapter also examines the impact of ligand and metal substitutions on Fe-oxo reactivity, highlighting the role of carboxylate-rich macrocycles and mediators. It identifies key gaps in the current literature, with particular attention to recent advancements in the field. These insights are critical for guiding the rational design of next-generation catalysts that aim to improve performance and selectivity. The chapter concludes by outlining the objectives of the current research, which seeks to address these identified gaps. Chapter two introduces the core principles and methods of computational chemistry, starting with quantum mechanics and the Schrödinger equation. It covers approximations like the Born-Oppenheimer and Hartree-Fock methods, addressing their limitations in electron-electron correlations. The chapter also explores post-Hartree-Fock methods and Density Functional Theory (DFT), highlighting its balance between efficiency and accuracy. Key computational tools, such as Gaussian 16 for geometry optimization and Chemcraft for molecular visualization, are discussed. The chapter lays the foundation for understanding computational chemistry techniques used in the research, setting the stage for further exploration. Chapter three presents a DFT study on C H activation reactivity and quantum mechanical tunneling in catalysis by a non-heme iron(IV)-oxo complex, [FeIV(O)(dpaq-X)]+. The study incorporates solvent and counter-ion corrections to eliminate self-interaction errors. The dpaq ligand was modified at the 5-position of its quinoline moiety, resulting in dpaq-X, and its reactivity