title: Catalytic transfer hydrogenation by a trivalent phosphorus compound: phosphorus-ligand cooperation pathway or P(III) /P(V) redox pathway?
abstract: Main-group-element catalysts are a desirable alternative to transition-metal catalysts because of natural abundance and cost. However, the examples are very limited. Catalytic cycles involving a redox process and E-ligand cooperation (E=main-group element), which are often found in catalytic cycles of transition-metal catalysts, have not been reported. Herein theoretical investigations of a catalytic hydrogenation of azobenzene with ammonia-borane using a trivalent phosphorus compound, which was experimentally proposed to occur through P(III) /P(V) redox processes via an unusual pentavalent dihydridophosphorane, were performed. DFT and ONIOM(CCSD(T):MP2) calculations disclosed that this catalytic reaction occurs through a P-O cooperation mechanism, which resembles the metal-ligand cooperation mechanism of transition-metal catalysts.
authors.affiliation: Fukui Institute for Fundamental Chemistry, Kyoto University, Takano-Nishihiraki-cho 34-4, Sakyo-ku, Kyoto 606-8103 (Japan).
authors.forename: Guixiang
authors.initials: G
authors.lastname: Zeng
authors.forename: Satoshi
authors.initials: S
authors.lastname: Maeda
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Taketsugu
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Sakaki
keywords: density functional calculations; hydrogenation; main-group elements; phosphorus; redox chemistry