title: Why Does the Intramolecular Trimethylene-Bridged Frustrated Lewis Pair Mes2 PCH2 CH2 CH2 B(C6 F5 )2 Not Activate Dihydrogen?
abstract: The methyl labelled C3 -bridged frustrated phosphane borane Lewis pair (P/B FLP) 2 b was prepared by treatment of Mes2 PCl with a methallyl Grignard reagent followed by anti-Markovnikov hydroboration with Piers' borane [HB(C6 F5 )2 )]. The FLP 2 b is inactive toward dihydrogen under typical ambient conditions, in contrast to the C2 - and C4 -bridged FLP analogues. Dynamic NMR spectroscopy showed that this was not due to kinetically hindered P⋅⋅⋅B dissociation of 2 b. DFT calculations showed that the hydrogen-splitting reaction of the parent compound 2 a is markedly endergonic. The PH(+) /BH(-) H2 -splitting product of 2 b was indirectly synthesized by a sequence of H(+) /H(-) addition. It lost H2 at ambient conditions and confirmed the result of the DFT analysis.
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Özgün
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
authors.forename: Ke-Yin
authors.initials: KY
authors.lastname: Ye
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
authors.forename: Constantin G
authors.initials: CG
authors.lastname: Daniliuc
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Wibbeling
authors.affiliation: Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstraße 4, 53115, Bonn, Germany.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstraße 4, 53115, Bonn, Germany.
authors.forename: Stefan
authors.identifier: http://orcid.org/0000-0002-5844-4371
authors.initials: S
authors.lastname: Grimme
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Kehr
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany. erker@uni-muenster.de.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Erker
keywords: boron; density functional calculations; dihydrogen activation; frustrated Lewis pair; phosphorus