Battistella, BeatriceIffland‐Mühlhaus, LindaSchütze, MaximillianCula, BeatriceKuhlmann, UweDau, HolgerHildebrandt, PeterLohmiller, ThomasMebs, StefanApfel, Ulf-PeterRay, Kallol2023-08-282023-08-282022-12-292023-05-05http://edoc.hu-berlin.de/18452/27839In many metalloenzymes, sulfur-containing ligands participate in catalytic processes, mainly via the involvement in electron transfer reactions. In a biomimetic approach, we now demonstrate the implication of S-ligation in cobalt mediated oxygen reduction reactions (ORR). A comparative study between the catalytic ORR capabilities of the four-nitrogen bound [Co(cyclam)]2+ (1; cyclam=1,5,8,11-tetraaza-cyclotetradecane) and the S-containing analog [Co(S2N2-cyclam)]2+ (2; S2N2-cyclam=1,8-dithia-5,11-diaza-cyclotetradecane) reveals improved catalytic performance once the chalcogen is introduced in the Co coordination sphere. Trapping and characterization of the intermediates formed upon dioxygen activation at the CoII centers in 1 and 2 point to the involvement of sulfur in the O2 reduction process as the key for the improved catalytic ORR capabilities of 2.eng(CC BY-NC 4.0) Attribution-NonCommercial 4.0 InternationalCobaltMacrocyclic LigandsO−O ActivationReactive IntermediatesSpectroscopy540 Chemie und zugeordnete Wissenschaftenarticleurn:nbn:de:kobv:11-110-18452/27839-610.18452/27180