Mixed-ligand complexes of paddlewheel dinuclear molybdenum as hydrodehalogenation catalysts for polyhaloalkanes.

ABSTRACT: We developed a hydrodehalogenation reaction of polyhaloalkanes catalyzed by paddlewheel dimolybdenum complexes in combination with 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene (MBTCD) as a non-toxic H-atom source as well as a salt-free reductant. A mixed-ligated dimolybdenum complex Mo₂(OAc)₂[CH(NAr)₂]₂ (3a, Ar = 4-MeOC₆H₄) having two acetates and two amidinates exhibited high catalytic activity in the presence of ⁿ Bu₄NCl, in which [ ⁿ Bu₄N]₂[Mo₂{CH(NAr)₂}₂Cl₄] (9a), derived by treating 3a with ClSiMe₃ and ⁿ Bu₄NCl, was generated as a catalytically-active species in the hydrodehalogenation. All reaction processes, oxidation and reduction of the dimolybdenum complex, were clarified by control experiments, and the oxidized product, [ ⁿ Bu₄N][Mo₂{CH(NAr)₂}₂Cl₄] (10a), was characterized by EPR and X-ray diffraction studies. Kinetic analysis of the hydrodehalogenation reaction as well as a deuterium-labelling experiment using MBTCD-d₈ suggested that the H-abstraction was the rate-determining step for the catalytic reaction.

SUBMITTER: Tsurugi H 

PROVIDER: S-EPMC5659211 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature