A Solvent-Responsive Terbium-Organic Framework for Photocatalytic CO2 Reduction.

A Tb-MOF with a 5,5,6-c 3-nodal net, {[Tb(DTDA)1.5·2H2O]·DMF·8H2O}n (AQNU-4), has been synthesized (DTDA = 2',5'-diethoxy-[1,1':4',1''-terphenyl]-4,4''-dicarboxylic acid). AQNU-4 contains a 1-periodic secondary building unit (rod SBU) and has an unusual topological type with the point symbol {32·44·62·7·8}{32·46·5·6}{32·46·52·65}. Efficient light harvesting and electron-hole separation make AQNU-4 an effective photocatalyst for use in the CO2 reduction reaction (CO2RR). Interestingly, as a photocatalyst, AQNU-4 shows an obvious solvent dependence during the catalytic process. In cyclohexanone in particular, it shows the highest CO2 to CO conversion, reaching 138.65 μmol g-1 h-1, making AQNU-4 a good solvent-responsive MOF material.