| Autor: |
Friães S; ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157 Oeiras, Portugal., Realista S; ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157 Oeiras, Portugal., Gomes CSB; LAQV-REQUIMTE, Department of Chemistry, Campus de Caparica, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal.; Associated Laboratory i4HB-Institute for Health and Bioeconomy, School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal.; UCIBIO-Applied Molecular Biosciences Unit, Department of Chemistry, School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal., Martinho PN; Biosystems and Integrative Sciences Institute (BioISI), Faculdade de Ciências, Campo Grande, Universidade de Lisboa, 1749-016 Lisboa, Portugal.; Centro de Química Estrutural, Campo Grande, Faculdade de Ciências Universidade de Lisboa, 1749-016 Lisboa, Portugal., Royo B; ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157 Oeiras, Portugal. |
| Abstrakt: |
A series of new fac -[Mn(L)(CO) 3 Br] 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) 3 Br] ( 4 ) to catalyze the electroreduction of CO 2 has been assessed for the first time. It was found that all complexes displayed a current increase under CO 2 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 CO 2 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). |
