Diiodo-BODIPY Sensitizing of the [Mo 3 S 13 ] 2- Cluster for Noble-Metal-Free Visible-Light-Driven Hydrogen Evolution within a Polyampholytic Matrix.

We report on a photocatalytic setup that utilizes the organic photosensitizer (PS) diiodo-BODIPY and the non-precious-metal-based hydrogen evolution reaction (HER) catalyst (NH 4 ) 2 [Mo 3 S 13 ] together with a polyampholytic unimolecular matrix poly(dehydroalanine)- graft -poly(ethylene glycol) (PDha- g -PEG) in aqueous media. The system shows exceptionally high performance with turnover numbers (TON > 7300) and turnover frequencies (TOF > 450 h -1 ) that are typical for noble-metal-containing systems. Excited-state absorption spectra reveal the formation of a long-lived triplet state of the PS in both aqueous and organic media. The system is a blueprint for developing noble-metal-free HER in water. Component optimization, e.g., by modification of the meso substituent of the PS and the composition of the HER catalyst, is further possible.