Structural modifications on nickel dithiolene complexes lead to increased metal participation in the electrocatalytic hydrogen evolution mechanism

Abstract

In this work we present the electrocatalytic activity of alkylated nickel bis-dithiolene complexes toward hydrogen evolution from protons (TFA) in organic media (DMF). The hydrogen evolving mechanism is discussed and the complexes are compared to their non-alkylated analogs using DFT calculations. The findings support increased metal participation in the hydrogen evolving mechanism due to the structural and electronic modifications imposed by the alkyl-bridge on the sulfur atoms. Typically for this class of compounds, the coordinated sulfur atoms act as internal proton relays that facilitate transfer of protons to the metal ion during the catalytic cycle, highlighting the importance of modifying the coordination sphere of metal ions in the design of homogeneous hydrogen evolving catalysts.

Graphical Abstract

Keywords:

• Dithiolene
• dithiolate
• hydrogen
• electrocatalysis
• nickel

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Special Research Account of National and Kapodistrian University of Athens (16672). It is also based upon work from COST Action 18234, supported by COST (European Cooperation in Science and Technology. M. D. The research work was supported by the Hellenic Foundation for Research and Innovation (HFRI) under the HFRI PhD Fellowship grant (Fellowship Number: 16199).