title: Spectroscopic Characterization of a Monomeric, Cyclopentadienyl-Based Rhenium(V) Dioxo Complex.
abstract: Mononuclear, coordinatively unsaturated rhenium(V) dioxo species of the type XReO2 (X = Me, substituted cyclopentadienyl) have long been postulated as intermediates in rhenium-catalyzed deoxydehydration, but their characterization was precluded because of aggregation into dimeric or oligomeric structures. Using the bulky 1,2,4-tri-tert-butylcyclopentadienyl (Cp(ttt)) ligand, the rhenium(V) dioxo species (Cp(ttt))ReO2 could now be observed, in equilibrium with the dimeric form [(Cp(ttt))Re(O)μ-O]2, and characterized by NMR, IR, and UV-vis spectroscopies, as well as electrospray ionization mass spectrometry. (Cp(ttt))ReO2 is shown to be the primary product of reduction of the rhenium(VII) complex (Cp(ttt))ReO3 with PPh3 and demonstrated to react with ethylene glycol significantly faster than its dimeric counterpart, supporting its role as an intermediate in rhenium-catalyzed deoxydehydration reactions.
authors.affiliation: Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University , Universiteitsweg 99, Utrecht 3584 CG, The Netherlands.
authors.forename: Suresh
authors.initials: S
authors.lastname: Raju
authors.affiliation: Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University , Universiteitsweg 99, Utrecht 3584 CG, The Netherlands.
authors.forename: Johann T B H
authors.initials: JT
authors.lastname: Jastrzebski
authors.affiliation: Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University , Padualaan 8, Utrecht 3584 CH, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Lutz
authors.affiliation: Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University , Universiteitsweg 99, Utrecht 3584 CG, The Netherlands.
authors.forename: Léon
authors.initials: L
authors.lastname: Witteman
authors.affiliation: Department of Chemistry, Technical University of Denmark , Kemitorvet 207, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Johannes R
authors.initials: JR
authors.lastname: Dethlefsen
authors.affiliation: Department of Chemistry, Technical University of Denmark , Kemitorvet 207, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Fristrup
authors.affiliation: Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University , Universiteitsweg 99, Utrecht 3584 CG, The Netherlands.
authors.forename: Marc-Etienne
authors.initials: ME
authors.lastname: Moret
authors.affiliation: Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University , Universiteitsweg 99, Utrecht 3584 CG, The Netherlands.
authors.forename: Robertus J M Klein
authors.initials: RJ
authors.lastname: Gebbink