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Electrochemical CO 2 and Proton Reduction by a Co(dithiacyclam) Complex
Author(s) -
Iffland Linda,
Siegmund Daniel,
Apfel UlfPeter
Publication year - 2020
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201900356
Subject(s) - cyclam , chemistry , electrochemistry , moiety , faraday efficiency , sulfur , acetic acid , solvent , inorganic chemistry , combinatorial chemistry , electrode , medicinal chemistry , stereochemistry , organic chemistry , metal
While [Ni(cyclam)] 2+ and [Ni(dithiacyclam)] 2+ complexes were shown to be potent electrocatalysts for the CO 2 conversion, their respective Co complexes hitherto received only little attention. Herein, we report on the Co II complexes of the cyclam and dithiacyclam platform, describe their synthesis and reveal their rich solvent dependent coordination chemistry. We show that sulfur implementation into the cyclam moiety leads to a switch from a low spin Co II complex in [Co(cyclam)] 2+ to a high spin form in [Co(dithiacyclam)] 2+ . Notably, while both complexes are capable to perform the reduction of CO 2 to CO, H 2 formation is generally preferred. Along this line, the complexes were shown to enable proton reduction from acetic acid. However, in comparison to [Co(cyclam)] 2+ , the altered electronics make [Co(dithiacyclam)] 2+ complexes prone to deposit on the glassy carbon working electrode over time leading to an overall low faradaic efficiency for the reduction of protons or CO 2 .