title: Dimethylaminoborane (H2BNMe2) coordination to late transition metal centers: snapshots of the B-H oxidative addition process.
abstract: The reaction of cyclodiborazane [Me(2)N-BH(2)](2) with the chloro(dihydrogen) ruthenium complex RuHCl(η(2)-H(2))(P(i)Pr(3))(2) (1) led to the formation of the unsymmetricaly coordinated dimethylaminoborane complex RuHCl(H(2)BNMe(2))(P(i)Pr(3))(2) (2). The dimethylaminoborane coordination (H(2)BNMe(2)) to the ruthenium center in 2 was carefully studied by combining X-ray, multinuclear NMR, and density functional theory (DFT) techniques, and compared with the recently reported osmium analogue which was originally formulated as a σ-B-H borinium complex [OsH(2)Cl(HBNMe(2))(P(i)Pr(3))(2)] (4). All our data are in favor of a bis(σ-B-H) coordination mode at a very activated stage in the case of the ruthenium complex 2, whereas in the osmium complex 4, full oxidative addition is favored leading to a complex better formulated as an osmium(IV) boryl species with an α-agostic B-H interaction. The synthesis and characterization of the symmetrical dihydride complex RuH(2)(H(2)BNMe(2))(P(i)Pr(3))(2) (3) from addition of the lithium dimethylaminoborohydride to 1 is reported for comparison.
authors.affiliation: LCC (Laboratoire de Chimie de Coordination), CNRS, 205 Route de Narbonne, F-31077 Toulouse, France.
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Bénac-Lestrille
authors.forename: Ulrike
authors.initials: U
authors.lastname: Helmstedt
authors.forename: Laure
authors.initials: L
authors.lastname: Vendier
authors.forename: Gilles
authors.initials: G
authors.lastname: Alcaraz
authors.forename: Eric
authors.initials: E
authors.lastname: Clot
authors.forename: Sylviane
authors.initials: S
authors.lastname: Sabo-Etienne