Abstract
A series of new fac-[Mn(L)(CO)3Br] complexes where L is a bidentate chelating ligand containing mixed mesoionic triazolylidene-pyridine (MIC^py, 1), triazolylidene-triazole (MIC^trz, 2), and triazole-pyridine (trz^py, 3) ligands have been prepared and fully characterized, including the single crystal X-ray diffraction studies of 1 and 2. The abilities of 1–3 and complex fac-[Mn(MIC^MIC)(CO)3Br] (4) to catalyze the electroreduction of CO2 has been assessed for the first time. It was found that all complexes displayed a current increase under CO2 atmosphere, being 3 and 4 the most active complexes. Complex 3, bearing a N^N-based ligand exhibited a good efficiency and an excellent selectivity for reducing CO2 to CO in the presence of 1.0 M of water, at low overpotential. Interestingly, complex 4 containing the strongly electron donating di-imidazolylidene ligand exhibited comparable activity to 3, when the experiments were performed in neat acetonitrile at slightly higher overpotential (−1.86 vs. −2.14 V).
Highlights
Nowadays, the synthesis of renewable fuels from carbon dioxide (CO2 ) is a key strategy to solve the problems of global warming and fossil fuel shortages [1]
Among the available methods for CO2 fixation, the electrocatalytic reduction of CO2 represents a promising approach for the production of value-added chemicals as fuels [2,3]
Intensive research has been done on CO2 electrocatalytic reduction using molecular catalysts in the last decade [4]
Summary
The synthesis of renewable fuels from carbon dioxide (CO2 ) is a key strategy to solve the problems of global warming and fossil fuel shortages [1]. Several groups have investigated in detail the electrocatalytic activity of related pyridine-based Mn complexes [13,14,15,16,17]. Complexes of the general type fac-[Mn(pyNHC)(CO) X] (NHC = imidazole- and benzimidazole-NHCs) resulted to be catalytically the pyridine ring π-system is typically considered electron-deficient, triazolylidenes, an interesting subclass of NHC ligands, are strongly σ-donating ligands [28]. Pyridine ligands and explored their activity in the CO2 electrocatalytic reduction. We became interested in exploring the impact of the presence of triazolylidene, triazole, and pyridine fragments in the coordination sphere of Mn. While the pyridine ring π-system is typically considered electron-deficient, triazolylidenes, an interesting subclass of NHC ligands, are strongly σ-donating ligands [28]. Catalytic systems based on Mn-triazolylidene are limited to one example recently reported by us [26]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
