Robust Biological Hydrogen-Bonded Organic Framework with Post-Functionalized Rhenium(I) Sites for Efficient Heterogeneous Visible Light-Driven CO2 Reduction.

A robust 2,2'-bipyridine (bpy)-derived biological hydrogen-bonded framework (HOF-25) has been realized depending on guanine-quadruplex with the assistance of π-π interaction, which reacts with Re(CO) 5 Cl to give a post-functionalized HOF-25-Re. X-ray absorption fine structure spectroscopic study on HOF-25-Re confirms the covalent attachment of Re(bpy)(CO) 3 Cl segments to this HOF. Robust and recycled HOF-25-Re bearing photocatalytic Re(bpy)(CO) 3 Cl centers displays good heterogeneous catalytic activity towards carbon dioxide photoreduction in the presence of [Ru(bpy) 3 ]Cl 2 and triisopropanolamine in CH 3 CN under visible-light irradiation, with both high CO production rate of 1448 μmol g -1 h -1 and high selectivity of 93%. Under the same conditions, the experimental turnover number of HOF-25-Re (50) is about 8 times as that of the homogeneous control Re(bpy)(CO) 3 Cl. The sustainably regenerated HOF-25-Re via crystallization and post-modification processes shows recovered photocatalytic performance.