Unexpected ligand effect on the catalytic reaction rate acceleration for hydrogen production using biomimetic nickel electrocatalysts with 1,5-diaza-3,7-diphosphacyclooctanes

Abstract

© 2015 Elsevier B.V. All rights reserved. The two new nickel complexes [Ni(P^R<inf>2</inf>N^Ph(CH)Ph<inf>2</inf>)<inf>2</inf>]²⁺ (where R = Ph or o-Py) with cyclic 1,5-diaza-3,7-diphosphacyclooctane ligands have been synthesized. All complexes are effective electrocatalysts for hydrogen production using [(DMF)H]⁺ as proton source in acetonitrile. The bulky benzhydryl substituent at nitrogen atom leads to higher catalytic activity comparison to benzyl. The introduction o-Py substituents at phosphorus as additional basic center is caused by the changing of voltage-current picture and significantly catalytic current enhancement. TOFs being 100 and 15200 s^-1 for R = Ph and o-Py, respectively.