Unravelling Photoinduced Electron Transfer Dynamics in Covalently Linked Bimetallic Complexes

Abstract

Photoinduced electron transfer (PET) processes are crucial in solar energy conversion and photocatalysis. Understanding the mechanism is very important to improve the efficiency and selectivity of PET. Bimetallic complexes that couple transition metal chromophores and catalytic centers with a bridging ligand are ideal molecular architectures for studying PET processes because they resemble photosynthetic molecules with multiple transition metal centers occurring in nature and through careful ligand design, explicit control of molecular geometry can be achieved. In this thesis, modern computational chemistry methods are employed to unravel excited state electronic and structural dynamics of bimetallic complexes. In Chapter 1, an introduction to the theoretical background in density functional theory and electron-nuclear dynamics is given. We then briefly review previous studies on bimetallic complexes and discuss the conformational differences in selected bimetallic complexesbetween the solution phase and solid state at ground state in Chapter 2. In Chapter 3, we study bridge-mediated metal-to-metal electron and hole transfer initiated by a photoinduced metal-to-ligand charge transfer excitation. In the last chapter, we establish the site-specificness of static nitrogen K-edge in the bimetallic complexes, laying the foundation for future time-resolved nitrogen K-edge experiments. Overall, the results shown in the thesis can help support static and time-resolved N K-edge X-ray absorption spectra experiments on bimetallic complexes and provide insights into the rational design of these complexes.