Transition metal complexes that participate in homogeneous reactions often perform the role of a catalyst, facilitating novel reaction pathways. When these complexes are pushed away from their equilibrium, the arrangement of the coordinating ligands around the metal center is perturbed and new reaction pathways are opened. By using a light-induced “trigger” to push the metal complex away from its equilibrium, this process can be initiated with precision. This thesis is concerned with the theoretical understanding of light-induced “triggered” reactions that generate transient, short-lived photoproducts in solution, capable of reacting with the surrounding solvent medium. A combination of theoretical and experimental tools are employed to give precise information about the formation and decay of these transient photoproducts.

In an effort to understand the innate differences between a broad range of transition metal complexes, electron configurations of the metal and its coordinating ligands are a natural starting point. These distinct electronic structures define the physical structure of the transition metal complex and explain the reactivity or lack of reactivity of the transition metal complex. To describe these electronic structures, robust quantum chemistry methods are required. Coinciding with these methods is a theoretical framework that aims to simulate the evolution of molecules by means of a molecular dynamics simulation.

The present work involves the study of ironpentacarbonyl or Fe(CO)₅ which we use to explain the reactive landscape of a broad class of carbonyl coordinated transition metal complexes. The part of the thesis devoted to Fe(CO)₅ is divided into distinct sections (i) the short-time (femtosecond-to-picosecond) gas-phase excited state molecular dynamics that produces the transient species, (ii) the long-time (picosecond-to-nanosecond) liquid-phase ground state molecular dynamics which describes the intermediates formed by the transient species and (iii) the experimental probes of the former sections. A final part of the thesis connects carbonyl containing metal complexes to another broad and detailed class of nitrosyl containing metal complexes.