title: Heterolytic activation of hydrogen using frustrated Lewis pairs containing tris(2,2',2''-perfluorobiphenyl)borane.
abstract: The extremely sterically hindered borane tris(2,2',2''-perfluorobiphenyl)borane (PBB) has been structurally characterised. In combination with bulky nitrogen bases, it forms the 'frustrated Lewis pairs' (FLPs) PBB/2,2,6,6-tetramethylpiperidine (TMP) (1), PBB/1,4-diazobicyclo[2.2.2]-octane (DABCO) (2) and PBB/2,6-lutidine (lut) (3). These novel, unquenched acid-base pairs have been shown to effect facile room temperature heterolytic cleavage of dihydrogen to form the ammonium borate salts [2,2,6,6-Me(4)C(5)H(6)NH(2)][HB(C(12)F(9))(3)] (4) and [N(C(2)H(4))(3)NH][HB(C(12)F(9))(3)] (5), and lutidinium borate [2,6-Me(2)C(5)H(3)NH][HB(C(12)F(9))(3)] (6). Although these reactions are equilibria, the reverse reaction and release of hydrogen gas was not apparent at temperatures up to 120 °C. The relative Lewis acidity of PBB has been determined using the Gutmann-Beckett method.
authors.affiliation: Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR.
authors.forename: Samantha C
authors.initials: SC
authors.lastname: Binding
authors.forename: Hasna
authors.initials: H
authors.lastname: Zaher
authors.forename: F
authors.initials: F
authors.lastname: Mark Chadwick
authors.forename: Dermot
authors.initials: D
authors.lastname: O'Hare