Optimizing Photocatalytic H2 Production by Introduction of Pyrazinyls to WRCs and a New tris‐Rhenium Photosensitizer.

The replacement of pyridyl by pyrazinyl in ligands of polypyridyl‐based cobalt water reducing catalysts (WRC) shifts reduction potentials anodically. Together with a new, trinuclear ReI photosensitizer, these WRCs show strongly improved photocatalytic performances in turnover numbers (TONs) and maximal H2 evolution rate. Depending on the catalyst structure, up to 65 kTONs at 1 μM WRC concentration were reached. Under electrocatalytic conditions in both DMF and H2O, one of the reported WRCs displays remarkable stability, producing H2 steadily over 21 and 14 d, respectively. [ABSTRACT FROM AUTHOR]