Phenyl Silicates with Substituted Catecholate Ligands: Synthesis, Structural Studies and Reactivity.

While the generation of aryl radicals by photoredox catalysis is well-documented under reductive conditions, it has remained challenging under an oxidative pathway. Because of the easy photooxidation of alkyl bis-catecholato silicates, a general study on phenyl silicates bearing substituted catecholate ligands has been achieved. The newly synthesized phenyl silicates have been fully characterized and their reactivity has been explored. It was found that thanks to the substitution of the catecholate moiety and notably with the 4-cyanocatecholato ligand, the phenyl radical could be generated and trapped. Computational studies provided a rationale for these findings.