Estimation of electron transfer rate constants by static (optical and electrochemical) measurements

A kinetic study of the reduction of Co(NH3)(5)(DMSO)(3+) (DMSO = dimethylsu lfoxide) by Fe(CN)(6)(4-) has been carried out in several water-cosolvent m ixtures at 298.2 K. The cosolvents used were ethylene glycol, acetonitrile, methanol and glucose. The free energies of activation for this thermal ele ctron-transfer reaction have bean calculated from a combination of spectros copic and electrochemical data and compared with those obtained from the ki netic study. Quantitative agreement is found between both series of data. T his shows the possibility of estimating activation free energies for electr on transfer reactions from these (static) measurements. (C) 1999 Elsevier S cience B.V. All rights reserved.