title: Electronic Structure of a Formal Iron(0) Porphyrin Complex Relevant to CO2Reduction.
abstract: Iron porphyrins can act as potent electrocatalysts for CO2functionalization. The catalytically active species has been proposed to be a formal Fe(0) porphyrin complex, [Fe(TPP)]2-(TPP = tetraphenylporphyrin), generated by two-electron reduction of [FeII(TPP)]. Our combined spectroscopic and computational investigations reveal that the reduction is ligand-centered and that [Fe(TPP)]2-is best formulated as an intermediate-spin Fe(II) center that is antiferromagnetically coupled to a porphyrin diradical anion, yielding an overall singlet ground state. As such, [Fe(TPP)]2-contains two readily accessible electrons, setting the stage for CO2reduction.
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Römelt
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.|Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, P. R. China.
authors.forename: Jinshuai
authors.initials: J
authors.lastname: Song
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Maxime
authors.initials: M
authors.lastname: Tarrago
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.|Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States.
authors.forename: Julian A
authors.identifier: http://orcid.org/0000-0003-0883-2680
authors.initials: JA
authors.lastname: Rees
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Maurice
authors.initials: M
authors.lastname: van Gastel
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Thomas
authors.identifier: http://orcid.org/0000-0002-0399-7999
authors.initials: T
authors.lastname: Weyhermüller
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.|Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Serena
authors.initials: S
authors.lastname: DeBeer
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Eckhard
authors.initials: E
authors.lastname: Bill
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Neese
authors.affiliation: Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Shengfa
authors.identifier: http://orcid.org/0000-0001-9747-1412
authors.initials: S
authors.lastname: Ye