title: Catalytic amine-borane dehydrogenation by a PCP-pincer palladium complex: a combined experimental and DFT analysis of the reaction mechanism.
abstract: Catalytic dehydrogenation of ammonia-borane (NH(3)·BH(3), AB) and dimethylamine borane (NHMe(2)·BH(3), DMAB) by the Pd(II) complex [((tBu)PCP)Pd(H(2)O)]PF(6) [(tBu)PCP = 2,6-C(6)H(3)(CH(2)P(t)Bu(2))(2)] leads to oligomerization and formation of spent fuels of general formula cyclo-[BH(2)-NR(2)](n) (n = 2,3; R = H, Me) as reaction byproducts, while one equivalent of H(2) is released per amine-borane equivalent. The processes were followed through multinuclear ((31)P, (1)H, (11)B) variable temperature NMR spectroscopy; kinetic measurements on the hydrogen production rate and the relative rate constants were also carried out. One non-hydridic intermediate could be detected at low temperature, whose chemical nature was explored through a DFT modeling of the reaction mechanism, at the M06//6-31+G(d,p) computational level. The computational output was of help to propose a reliable mechanistic picture of the process.
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organometallici, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze), Italy. a.rossin@iccom.cnr.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossin
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bottari
authors.forename: Ana M
authors.initials: AM
authors.lastname: Lozano-Vila
authors.forename: Margarita
authors.initials: M
authors.lastname: Paneque
authors.forename: Maurizio
authors.initials: M
authors.lastname: Peruzzini
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Zanobini