Organometallic Ni Pincer Complexes for the Electrocatalytic Production of Hydrogen

Nonplatinum metals are needed to perform cost-effective
water reduction
electrocatalysis to enable technological implementation of a proposed
hydrogen economy. We describe electrocatalytic proton reduction and
H2 production by two organometallic nickel complexes with
tridentate pincer ligands. The kinetics of H2 production
from voltammetry is consistent with an overall third order rate law:
the reaction is second order in acid and first order in catalyst.
Hydrogen production with 90–95% Faradaic yields was confirmed
by gas analysis, and UV–vis spectroscopy suggests that the
ligand remains bound to the catalyst over the course of the reaction.
A computational study provides mechanistic insights into the proposed
catalytic cycle. Furthermore, two proposed intermediates in the proton
reduction cycle were isolated in a representative system and show
a catalytic response akin to the parent compound.