title: An Inverted-Sandwich Diuranium μ-η5:η5-Cyclo-P5Complex Supported by U-P5δ-Bonding.
abstract: Reaction of [U(TrenTIPS)] [1, TrenTIPS=N(CH2CH2NSiiPr3)3] with 0.25 equivalents of P4reproducibly affords the unprecedented actinide inverted sandwich cyclo-P5complex [{U(TrenTIPS)}2(μ-η5:η5-cyclo-P5)] (2). All prior examples of cyclo-P5are stabilized by d-block metals, so2shows that cyclo-P5does not require d-block ions to be prepared. Although cyclo-P5is isolobal to cyclopentadienyl, which usually bonds to metals via σ- and π-interactions with minimal δ-bonding, theoretical calculations suggest the principal bonding in the U(P5)U unit is polarized δ-bonding. Surprisingly, the characterization data are overall consistent with charge transfer from uranium to the cyclo-P5unit to give a cyclo-P5charge state that approximates to a dianionic formulation. This is ascribed to the larger size and superior acceptor character of cyclo-P5compared to cyclopentadienyl, the strongly reducing nature of uranium(III), and the availability of uranium δ-symmetry 5f orbitals.
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD (UK).
authors.forename: Benedict M
authors.initials: BM
authors.lastname: Gardner
authors.affiliation: School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL (UK).
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.affiliation: School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL (UK).
authors.forename: Eric J L
authors.initials: EJ
authors.lastname: McInnes
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD (UK).
authors.forename: Jonathan
authors.initials: J
authors.lastname: McMaster
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD (UK).
authors.forename: William
authors.initials: W
authors.lastname: Lewis
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD (UK).
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Blake
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD (UK).
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Liddle
keywords: Dichtefunktionaltheorie; Phosphor; Uran; cyclo‐P5; δ‐Bindung