Influence of the oxygen atom acceptor on the reaction coordinate and mechanism of oxygen atom transfer from the dioxo-Mo(VI) complex, Tp(iPr)MoO(2)(OPh), to tertiary phosphines.

ABSTRACT: The oxygen atom transfer reactivity of the dioxo-Mo(VI) complex, Tp(iPr)MoO(2)(OPh) (Tp(iPr) = hydrotris(3-isopropylpyrazol-1-yl)borate), with a range of tertiary phosphines (PMe(3), PMe(2)Ph, PEt(3), PBu(n)(3), PEt(2)Ph, PEtPh(2), and PMePh(2)) has been investigated. The first step in all the reactions follows a second-order rate law indicative of an associative transition state, consistent with nucleophilic attack by the phosphine on an oxo ligand, namely, Tp(iPr)MoO(2)(OPh) + PR(3) --> Tp(iPr)MoO(OPh)(OPR(3)). The calculated free energy of activation for the formation of the OPMe(3) intermediate (Chem. Eur. J. 2006, 12, 7501) is in excellent agreement with the experimental DeltaG() value reported here. The second step of the reaction, that is, the exchange of the coordinated phosphine o

SUBMITTER: Basu P 

PROVIDER: S-EPMC2897133 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature