Mechanism of SN2 disulfide bond cleavage by phosphorus nucleophiles. Implications for biochemical disulfide reducing agents.

ABSTRACT: The B3LYP variant of DFT has been used to study the mechanism of S-S bond scission in dimethyl disulfide by a phosphorus nucleophile, trimethylphospine (TMP). The reaction is highly endothermic in the gas phase and requires significant external stabilization of the charged products. DFT calculations (B3LYP) were performed with explicit (water molecules added) and implicit solvent corrections (COSMO model). The transition structures for this SN2 displacement reaction in a number of model systems have been located and fully characterized. The reaction barriers calculated with different approaches for different systems are quite close (around 11 kcal/mol). Remarkably, the calculations suggest that the reaction is almost barrierless with respect to the preorganized reaction complex and that mo

SUBMITTER: Dmitrenko O 

PROVIDER: S-EPMC2613176 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature