Mechanistic Insight into Metal-Ligand Bond Homolysis Mediated by a Secondary Coordination Sphere Photosensitizer

Abstract

Inspired by the prevalence of secondary coordination sphere interactions in nature, prior work in the Roque group has developed a Ni(II) bis(trifluoromethyl) complex with an appended photosensitizer in the secondary coordination sphere. The secondary coordination sphere photosensitizer has been shown to unlock new photophysical pathways which facilitate an unprecedented light-driven Ni-CF3 bond homolysis. This work further studies this complex by probing the effects of appending electron-donating and withdrawing groups on both the photosensitizer and the ligand backbone. These studies provide further support for the proposed photophysical mechanism and demonstrate that ligand derivatization can have noticeable impacts on the solubility, reactivity, and photophysics of the complex. The insight from this work helps to inform key design principles for future iterations of this concept. Additionally, work towards developing substrate scope for the migratory arylation of alcohols is presented.