A nickel complex of 2,2-dicyanoethylene-1,1-dithiolate, a catalyst for electrochemical and photochemical driven hydrogen evolution.

The reaction of NiCl₂, K₂(i-mnt) (i-mnt²⁻= 2,2-dicyanoethylene-1,1-dithiolate) and 1-benzyl-4-amino-pyridinium bromide [BzPyNH₂]Br affords a nickel complex, [BzPyNH₂]₂[Ni(i-mnt)₂], a molecular catalyst for electrochemical and photochemical driven hydrogen evolution. As an electrocatalyst, [BzPyNH₂]₂[Ni(i-mnt)₂] can electrocatalyze hydrogen generation from a neutral buffer with a turnover frequency (TOF) of 556 (±3) mol of hydrogen per mole of catalyst per hour (mol H₂/mol catalyst/h) at an overpotential (OP) of 837.6 mV. As a photocatalyst, combining with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H₂A) as a sacrificial electron donor, [BzPyNH₂]₂[Ni(i-mnt)₂] photocatalyzes hydrogen evolution in heterogeneous environments with a turnover number (TON) of 18420 (±5) mol H₂ per mol of catalyst during 60 h irradiation. The highest apparent quantum yield (AQY) is ∼10% at 469 nm. Several chemical and physical methods are employed to understand catalytic procedures for H₂ production. [ABSTRACT FROM AUTHOR]