Supramolecular assemblies of Cu(II) with a tetraphenylethene-imidazole ligand for tuning photocatalytic CO 2 reduction.

Cu(II) supramolecular assemblies [Cu 2 (tipe) 2 (H 2 O) 2 ](NO 3 ) 4 ·2.5H 2 O (CuN4) and [Cu 2 Cl 4 (tipe)(CH 3 CN)]·H 2 O (CuN2Cl2) (tipe = 1,1,2,2-tetrakis(4-(imidazole-1-yl)phenyl)ethene) were synthesized and utilized for photocatalytic CO 2 reduction. CuN4 exhibits CO production of up to 891 μmol g cat -1 with a selectivity of 79.9%, while CuN2Cl2 gives low CO production of 206 μmol g cat -1 but with a high selectivity of >99.9% in 5 h. The experimental and DFT calculation results indicate that the coordination environment and non-covalent interactions within the assemblies have a great impact on the photocatalytic CO 2 reduction behavior. This work provides useful insights on Cu(II) assembly catalyzed CO 2 photoreduction.