Local Proton Source in Electrocatalytic CO2 Reduction with [Mn(bpy-R)(CO)(3)Br] Complexes

0473905 - ÚFCH JH 2018 RIV DE eng J - Journal Article
Franco, F. - Cometto, C. - Nencini, L. - Barolo, C. - Sordello, F. - Minero, C. - Fiedler, Jan - Robert, M. - Gobetto, R. - Nervi, C.
Local Proton Source in Electrocatalytic CO2 Reduction with [Mn(bpy-R)(CO)(3)Br] Complexes.
Chemistry - A European Journal. Roč. 23, č. 20 (2017), s. 4782-4793. ISSN 0947-6539. E-ISSN 1521-3765
R&D Projects: GA ČR(CZ) GA14-05180S
Institutional support: RVO:61388955
Keywords : electrochemistry * electrocatalysis * [Mn(pdbpy)(CO)(3)Br] Complexes
OECD category: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Impact factor: 5.160, year: 2017

The electrochemical behavior of fac-[Mn(pdbpy)(CO)(3)Br] (pdbpy=4-phenyl-6-(phenyl-2,6-diol)-2,2-bipyridine) (1) in acetonitrile under Ar, and its catalytic performances for CO2 reduction with added water, 2,2,2-trifluoroethanol (TFE), and phenol are discussed in detail. Preparative-scale electrolysis experiments, carried out at -1.5V versus the standard calomel electrode (SCE) in CO2-saturated acetonitrile, reveal that the process selectivity is extremely sensitive to the acid strength, producing CO and formate in different faradaic yields. A detailed spectroelectrochemical (IR and UV/Vis) study under Ar and CO2 atmospheres shows that 1 undergoes fast solvolysis, however, dimer formation in acetonitrile is suppressed, resulting in an atypical reduction mechanism in comparison with other reported Mn-I catalysts. Spectroscopic evidence of Mn hydride formation supports the existence of different electrocatalytic CO2 reduction pathways. Furthermore, a comparative investigation performed on the new fac-[Mn(ptbpy)(CO)(3)Br] (ptbpy=4-phenyl-6-(phenyl-3,4,5-triol)-2,2-bipyridine) catalyst (2), bearing a bipyridyl derivative with OH groups in different positions to those in 1, provides complementary information about the role that the local proton source plays during the electrochemical reduction of CO2.
Permanent Link: http://hdl.handle.net/11104/0271016