Homogeneous Electrochemical Reduction of CO₂ to CO by a Cobalt Pyridine Thiolate Complex

Abstract

The chemical and electrochemical reduction of CO2 to value added chemicals entails the development of efficient and selective catalysts. Synthesis, characterization and electrochemical CO2 reduction activity of a air-stable cobalt­(III) diphenylphos­phenethano-bis­(2-pyridinethiolate)­chloride [{Co­(dppe)­(2-PyS)2}­Cl, 1-Cl] complex is divulged. The complex reduces CO2 under homogeneous electrocatalytic conditions to produce CO with high Faradaic efficiency (FE > 92%) and selectivity in the presence of water. Through detailed electrochemical investigations, product analysis, and mechanistic investigations supported by theoretical calculations, it is established that complex 1-Cl reduces CO2 in its Co­(I) state. A reductive cleavage leads to a dangling protonated pyridine arm which enables facile CO2 binding through a H-bond donation and facilitates the C–O bond cleavage via a directed protonation. A systematic benchmarking of this catalyst indicates that it has a modest overpotential (∼180 mV) and a TOF of ∼20 s–1 for selective reduction of CO2 to CO with H2O as a proton source.

Promoting photocatalytic CO2 reduction through facile electronic modification of N-annulated perylene diimide rhenium bipyridine dyads

“…61,62 Moreover, these CV current enhancements may be monitored as a function of catalyst or proton-source concentration as a means to gather preliminary mechanistic data on the catalytic process (see SI, equation ii). 63,64 When the Re(bpy-C2-NPDI-R) concentration was varied, a linear CV current enhancement response was also observed for most dyads (Figure S68). Similarly, when proton-source 2,2,2trifluoroethanol (TFE) was incrementally added to a CO 2 -saturated Re(bpy-C2-NPDI-R) dyad solution, it induced a CV current enhancement increase under the fourth reduction event (Figure 3).…”

Transition Metal Complexes as Catalysts for the Electroconversion of CO2: An Organometallic Perspective

“…92 AE 4 [263] (CO + H 2 ) 64 [264] 19 [264] ET M (CO) ET H (HCO 2 H/H 2 ) comp. DFT [263,264] 14 -n .a. n.a.…”

Übergangsmetallkomplexe als Katalysatoren für die elektrische Umwandlung von CO2 – eine metallorganische Perspektive

“…[184] n.v. [259] 23 [260] ET M post. n.v. 92 AE 4 [263] (CO + H 2 ) 64 [264] 19 [264] ET 83 [269] 59 [269] 29 [269] ET M post. n.v. [269,271] 96 [277] 15 [274] ET H exp.…”