Synthesis; characterization and electrocatalytic properties of a tetranuclear triazenido-copper(I) complex

A new molecular catalyst based on a tetra-nuclear copper(I), [Cu-4(I)(L)(4)]1 is prepared by the reaction of the triazenido ligand, [1,3-bis(2-methoxy)benzene]triazene (HL) with CuCI. X-ray structural studies show that four copper atoms are triazenido-bridged with four independent Cu center dot center dot center dot Cu distances of 2.5881(7)-2.6048 (7) angstrom. Complex 1 can act as an electrocatalyst for hydrogen generation with 170.66 mol of hydrogen per mole of catalyst per hour (mol h(-1)) from acetic acid at an overpotential (OP) of 991.6 mV and 1034.31 mol 11(-1) from a neutral aqueous buffer (pH 7.0) at an OP of 837.6 mV, respectively. To test that the triazenido ligand, HL, plays a role in the electrocatalytic system, electrocatalytic activities of HL, CuCI and 1 are each investigated, and a possible catalytic mechanism for hydrogen generation catalyzed by 1 is provided. (C) 2017 Elsevier Ltd. All rights reserved.