title: Rhodium Complexes Promoting C-O Bond Formation in Reactions with Oxygen: The Role of Superoxo Species.
abstract: C-O bond formation in reactions of olefins with oxygen is a long standing challenge in chemistry for which the very complicated-sometimes controversial-mechanistic panorama slows down the design of catalysts for oxygenations. In this regard, the mechanistic details of the oxidation of the complex [Rh(cod)(Ph2N3)] (1) (cod=1,5-cyclooctadiene) with oxygen to the unique 2-rhodaoxetane compound [{Rh(OC8H12)(Ph2N3)}2] (2) has been investigated by DFT calculations. The results of this study provide evidences for a novel bimetallic mechanism in which two rhodium atoms redistribute the four electrons involved in the cleavage of the O=O bond. Furthermore, both oxygen atoms are used to create two new C-O bonds in a controlled fashion with 100 % atom economy. The key intermediates that we have found in this process are a mononuclear open-shell triplet superoxo compound, an open-shell singlet "μ-(peroxo)" derivative, and a closed-shell singlet "bis(μ-oxo)" complex. Some of the findings are used to predict the reactions of RhIcomplexes with oxygen, exemplified by that of the complex [Rh(cod)(OnapyMe2)] (3). Starting from 3, [{Rh(OC8H12)(OnapyMe2)}2] (4) has been prepared and characterized, which represents the second example of a 2-rhodaoxetane compound coming from an oxygenation reaction with oxygen.
authors.affiliation: Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Vilella-Arribas
authors.affiliation: School of Chemistry, Trinity College Dublin, College Green, Dublin, 2, Ireland.
authors.forename: Max
authors.identifier: http://orcid.org/0000-0003-1348-4692
authors.initials: M
authors.lastname: García-Melchor
authors.affiliation: Centre for Theoretical and Computational Chemistry (CTCC) and Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315, Oslo, Norway.
authors.forename: David
authors.identifier: http://orcid.org/0000-0002-3389-0543
authors.initials: D
authors.lastname: Balcells
authors.affiliation: Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain.
authors.forename: Agustí
authors.identifier: http://orcid.org/0000-0001-7909-422X
authors.initials: A
authors.lastname: Lledós
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálsis Homogénea (ISQCH), CSIC Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: López
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálsis Homogénea (ISQCH), CSIC Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.
authors.forename: Sofía
authors.initials: S
authors.lastname: Sancho
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálsis Homogénea (ISQCH), CSIC Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.
authors.forename: B Eva
authors.initials: BE
authors.lastname: Villarroya
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálsis Homogénea (ISQCH), CSIC Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Del Río
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálsis Homogénea (ISQCH), CSIC Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.
authors.forename: Miguel A
authors.identifier: http://orcid.org/0000-0002-7188-8014
authors.initials: MA
authors.lastname: Ciriano
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálsis Homogénea (ISQCH), CSIC Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.
authors.forename: Cristina
authors.identifier: http://orcid.org/0000-0003-3306-0635
authors.initials: C
authors.lastname: Tejel
keywords: C−O bond formation; density functional calculations; dioxygen cleavage; rhodaoxetanes; rhodium