Electrochemical Water Oxidation Catalyzed by N-4-Coordinate Copper Complexes with Different Backbones: Insight into the Structure-Activity Relationship of Copper Catalysts

摘要

Copper complexes with a general formula of [(L)Cu(OH2)](BF4)(2) (1, L1=N,N '-dimethyl-N,N '-bis(pyridin-2-ylmethyl)-1,2-diaminoethane; 2, L2=N,N '-bis(pyridin-2-ylmethyl)piperazine); 3, L3=N,N '-bis(pyridin-2-ylmethyl)diazepane) were prepared as molecular catalysts for oxygen evolution reaction. These catalysts have the same first coordination environment but different backbones of diamine-dipyridine N-4-ligands. Single crystal X-ray diffraction studies on the molecular structures of 1-3 revealed that the backbone rigidity of the N-4-ligand has apparent influence on the N-py-Cu-N '(py) open angle of copper complexes. Comparative studies manifested that the subtle structural change caused by the backbone rigidity of N-4-ligands has an important influence on the catalytic performance and reaction pathway of copper catalysts for electrochemical water splitting.