title: Reactivity of a frustrated lewis pair and small-molecule activation by an isolable Arduengo carbene-B{3,5-(CF3)2C6H3}3 complex.
abstract: Tris[3,5-bis(trifluoromethyl)phenyl]borane reacts with the sterically demanding Arduengo carbenes 1,3-di-tert-butylimidazolin-2-ylidene and 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene to form isolable normal adducts. In the case of 1,3-di-tert-butylimidazolin-2-ylidene, the adduct exhibits dynamic behaviour in solution and frustrated-Lewis-pair (FLP) reactivity. Fast cleavage of dihydrogen and THF, the C-H activation of phenylacetylene, and carbon dioxide fixation were achieved by using solutions of this adduct in benzene. This adduct is stable at room temperature in the absence of suitable substrates; however, thermal rearrangement into an abnormal carbene-borane adduct can be observed. In contrast, the 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene adduct exhibits no evidence of FLP reactivity or of dissociation in solution. DFT calculations confirmed the experimental behaviour and stability of these carbene-borane adducts.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Germany.
authors.forename: Eugene L
authors.initials: EL
authors.lastname: Kolychev
authors.forename: Thomas
authors.initials: T
authors.lastname: Bannenberg
authors.forename: Matthias
authors.initials: M
authors.lastname: Freytag
authors.forename: Constantin G
authors.initials: CG
authors.lastname: Daniliuc
authors.forename: Peter G
authors.initials: PG
authors.lastname: Jones
authors.forename: Matthias
authors.initials: M
authors.lastname: Tamm