Periodic Trends\nand Fluxionality Effects on Transition\nMetal Catalyzed Sulfoxidation

Despite the extended interest in d<sup>0</sup> metal\ncomplexes\nas catalysts for peroxide activation and eventual oxygen transfer\nprocesses, there are still gaps in the understanding of how they proceed\nat the microscopic level. Herein, we have considered sulfide oxidation\nwith cumyl hydroperoxide as a test system, performing the reaction\nwith a series of eight different aminotriphenolate d<sup>0</sup> metal\ncomplexes: Ti(IV), Zr(IV), Hf(IV), V(V), Nb(V), Ta(V), Mo(VI), and\nW(VI). The reactivity and selectivity of the catalytic systems, as\nwell as the effect of a strong Lewis base (dimethylhexyl-<i>N</i>-oxide), have been determined experimentally, correlating kinetic\nvalues with Sanderson electronegativity values. Theoretical calculations\nof the catalytic cycles have been performed to have a clearer description\nof the role of the reactive peroxo species. Combining experimental\nresults and DFT predictions, we propose suitable mechanisms for all\neight metal aminotriphenolates, rationalizing the expected periodic\ntrends, while also unveiling the unique reaction pathways available\nto highly flexible vanadium complexes.