title: Local Proton Source in Electrocatalytic CO2Reduction with [Mn(bpy-R)(CO)3Br] Complexes.
abstract: The electrochemical behavior of fac-[Mn(pdbpy)(CO)3Br] (pdbpy=4-phenyl-6-(phenyl-2,6-diol)-2,2'-bipyridine) (1) in acetonitrile under Ar, and its catalytic performances for CO2reduction with added water, 2,2,2-trifluoroethanol (TFE), and phenol are discussed in detail. Preparative-scale electrolysis experiments, carried out at -1.5 V 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 CO2atmospheres shows that 1 undergoes fast solvolysis; however, dimer formation in acetonitrile is suppressed, resulting in an atypical reduction mechanism in comparison with other reported MnIcatalysts. Spectroscopic evidence of Mn hydride formation supports the existence of different electrocatalytic CO2reduction pathways. Furthermore, a comparative investigation performed on the new fac-[Mn(ptbpy)(CO)3Br] (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.
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Franco
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.|Univ. Paris Diderot, Sorbonne Paris Cité, UMR CNRS 7591, Laboratoire Electrochimie Moléculaire, 75205, Paris 13, France.
authors.forename: Claudio
authors.initials: C
authors.lastname: Cometto
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Nencini
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Barolo
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.
authors.forename: Fabrizio
authors.identifier: http://orcid.org/0000-0003-4578-2694
authors.initials: F
authors.lastname: Sordello
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.
authors.forename: Claudio
authors.identifier: http://orcid.org/0000-0001-9484-130X
authors.initials: C
authors.lastname: Minero
authors.affiliation: Heyrovský Institute of Physical Chemistry of ASCR v.v.i., Dolejškova 3, 18223, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Fiedler
authors.affiliation: Univ. Paris Diderot, Sorbonne Paris Cité, UMR CNRS 7591, Laboratoire Electrochimie Moléculaire, 75205, Paris 13, France.
authors.forename: Marc
authors.identifier: http://orcid.org/0000-0001-7042-4106
authors.initials: M
authors.lastname: Robert
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Gobetto
authors.affiliation: Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy.
authors.forename: Carlo
authors.identifier: http://orcid.org/0000-0002-3712-7369
authors.initials: C
authors.lastname: Nervi
keywords: carbon dioxide; density functional calculations; electrocatalysis; electrochemistry; manganese