The EPR Pattern of [CrO(cis-1,2-cyclopentanediolato)_2]~- and [CrO(trans-1,2-cyclopentanediolato)_2]~-

摘要

The addition of a large excess of 1,2-cyclopentanediol to a 1:1 mixture of glutathione and Cr~(VI) at pH 7.5 stabilises the intermediate Cr~V species formed by teh one-electron reduction of Cr~(VI) by glutathione.The isotropic EPR parameters (g_(iso) and A_(iso)) of the Cr~V species formed with both cis- and trans-1,2-cyclopentanediol correspond to those calculated for five-coordinate oxo-Cr~V complexes with four alcoholato donors [Cr(O)(1,2-cyclopentanediolato)_2]~-.The five-coordinate oxo-Cr~V species formed with both 1,2-cyclopentanediol isomers show very similar EPR superhyperfine patterns,but differ in their stability and the conditions required for their formation due to the different chelation ability of the cis- vs.trans-1,2-diolato moiety.