Electrocatalytic Carbon Dioxide Reduction by Using Cationic Pentamethylcyclopentadienyl–Iridium Complexes with Unsymmetrically Substituted Bipyridine Ligands |
| |
| Authors: | Fanni D. Sypaseuth Corinna Matlachowski Manuela Weber Dr. Matthias Schwalbe Prof. Dr. C. Christoph Tzschucke |
| |
| Affiliation: | 1. Institut für Chemie und Biochemie, Organische Chemie, Freie Universit?t Berlin, Takustrasse 3, 14195 Berlin (Germany);2. Institut für Chemie, Humboldt Universit?t zu Berlin, Brook‐Taylor Strasse 2, 12489 Berlin (Germany);3. Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universit?t Berlin, Fabeckstrasse 34/36, 14195 Berlin (Germany) |
| |
| Abstract: | Eight [Ir(bpy)Cp*Cl]+‐type complexes (bpy= bipyridine, Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) containing differently substituted bipyridine ligands were synthesized and characterized. Cyclic voltammetry (CV) of the complexes in Ar‐saturated acetonitrile solutions showed that the redox behavior of the complexes could be fine tuned by the electronic properties of the substituted bipyridine ligands. Further CV in CO2‐saturated MeCN/H2O (9:1, v/v) solutions showed catalytic currents for CO2 reduction. In controlled potential electrolysis experiments (MeCN/MeOH (1:1, v/v), Eapp=?1.80 V vs Ag/AgCl), all of the complexes showed moderate activity in the electrocatalytic reduction of CO2 with good stability over at least 15 hours. This electrocatalytic process was selective toward formic acid, with only traces of dihydrogen or carbon monoxide and occasionally formaldehyde as byproducts. However, the turnover frequencies and current efficiencies were quite low. No direct correlation between the redox potentials of the complexes and their catalytic activity was observed. |
| |
| Keywords: | bipyridine carbon dioxide electrochemistry homogeneous catalysis iridium |
|
|
