Transforming carbon dioxide into a methanol surrogate using modular transition metal-free Zintl ions

Although not the only greenhouse gas, CO₂ is the poster child. Unsurprisingly, therefore, there is global interest across industrial and academic research in its removal and subsequent valorisation, including to methanol and its surrogates. Although difficult to study, the heterogenous pnictogens represent one important category of catalytic materials for these conversions; their high crustal abundance and low cost offers advantages in terms of sustainability. Here, Zintl clusters based on these elements are studied as homogenous atom-precise models in CO₂ reduction. A family of group 13 functionalized pnictogen clusters with the general formula [(R₂E)Pn₇]^2- (E = B, Al, In; Pn = P, As) is synthesized and their catalytic competency in the reduction of CO₂ probed. Trends in both turnover numbers and frequencies are compared across this series, and [(iBu₂Al)P₇]^2- found to be very high-performing and recyclable. Electronic structures across the series are compared using density functional theory to provide mechanistic insights.