title: Even the normal is abnormal: N-heterocyclic carbene C(2) binding to a phosphaalkene without breaking the P=C π-bond.
abstract: The reaction of MesP=CPh2 with the least sterically demanding N-heterocyclic carbene (NHC = IMe) results in formation of the 'abnormal' (C(4)-substituted) 4-phosphino-NHC (1). In contrast, reaction with Me2IMe gives the unprecedented 'normal' C(2) adduct, Me2IMe → P(Mes)=CPh2 (2). Particularly striking is the asymmetric and weak bonding of the NHC to the P=C moiety in 2. DFT calculations indicate that the P=C natural bond order in 2 (1.54) still reflects significant π-character to the bond (cf. MesP=CPh2: NBO = 1.98). Further computational analysis suggests that π-delocalization into the remote C-phenyl substituents is key to stabilizing the NHC adduct.
authors.affiliation: Institut für Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany. r.streubel@uni-bonn.de and Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada. dgates@chem.ubc.ca.
authors.forename: Paresh Kumar
authors.initials: PK
authors.lastname: Majhi
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada. dgates@chem.ubc.ca.
authors.forename: Keith C F
authors.initials: KC
authors.lastname: Chow
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada. dgates@chem.ubc.ca.
authors.forename: Tom H H
authors.initials: TH
authors.lastname: Hsieh
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada. dgates@chem.ubc.ca.
authors.forename: Eric G
authors.initials: EG
authors.lastname: Bowes
authors.affiliation: Institut für Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany. r.streubel@uni-bonn.de.
authors.forename: Gregor
authors.initials: G
authors.lastname: Schnakenburg
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada. dgates@chem.ubc.ca.
authors.forename: Pierre
authors.initials: P
authors.lastname: Kennepohl
authors.affiliation: Institut für Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany. r.streubel@uni-bonn.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Streubel
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada. dgates@chem.ubc.ca.
authors.forename: Derek P
authors.initials: DP
authors.lastname: Gates