Non-coordinating counteranion as a powerful tool to tune the activity of copper water oxidation catalysts†
Abstract
Ten copper-bipyridine-type catalysts, [(bpyR)Cu(OH)2]2+, featuring diverse counteranions (OAc−, Cl−, SO42−, NO3−, OTf−) were synthesized. The observed substantial variations in turnover frequency (TOF) among these catalysts, coupled with insights gained from electrochemical investigations, underscore the pivotal influence of counteranions in fine-tuning the catalytic activity of metal complexes during water oxidation. The TOF value follows the trend of OAc− > Cl− > SO42− > NO3− > OTf−, which is the same as the change of coordinating ability index, a™. Density Functional Theory (DFT) calculations reveal that counteranion coordination plays an important role in influencing the catalytic performance of these complexes.