Enhanced photoreduction of water catalyzed by a cucurbit[8]uril-secured platinum dimer

A cucurbit[8]uril (CB[8])-secured platinum terpyridyl chloride dimer was used as a photosensitizer and hydrogen-evolving catalyst for the photoreduction of water. Volumes of produced hydrogen were up to 25 and 6 times larger than those obtained with the corresponding free and cucurbit[7]uril-bound platinum monomer, respectively, at equal Pt concentration. The thermodynamics of the proton-coupled electron transfer from the Pt(ii)-Pt(ii) dimer to the corresponding Pt(ii)-Pt(iii)-H hydride key intermediate, as quantified by density functional theory, suggest that CB[8] secures the Pt(ii)-Pt(ii) dimer in a particularly reactive conformation that promotes hydrogen formation.

Automated summary

A cucurbit[8]uril-secured platinum terpyridyl chloride dimer was utilized as a photosensitizer and hydrogen-evolving catalyst for the photoreduction of water, leading to significantly higher volumes of produced hydrogen compared to free platinum or cucurbit[7]uril-bound platinum monomer. Density functional theory calculations demonstrated that the thermodynamics of the proton-coupled electron transfer promoted by CB[8] secure the Pt(ii)-Pt(ii) dimer in a reactive conformation, ultimately facilitating hydrogen formation.