85283-43-8Relevant academic research and scientific papers
Charge-Transfer Perturbations of the Electronic Contributions to Electron-Transfer Reactions. Enhanced Donor-Acceptor Couplings Mediated by Coordinated Ligands
Endicott, John F.,Ramasami, T.
, p. 3740 - 3747 (1986)
The factors contributing to variations in the adiabaticity of a series of Co(III)-Co(sep)(2+) (sep= (S)-1,3,6,8,10,13,16,19-octaazabicycloeicosane) cross-reactions have been investigated.Coordinated ligands can be effective in making the electron-transfer rates more adiabatic by altering the electronic structure of the complex and/or by contributing to intermolecular charge-transfer interactions.Alterations of the coordinated ligands change both the ligand field and the charge-transfer excited states of the Co(III) acceptor, and the contributions of each kind of excited state perturbation must be considered in evaluating rate patterns.For Co(NH3)5X(2+) oxidants, the inferred values of the electronic transmission coefficient, κel, increase systematically through the series X=CN, Cl, Br, N3, and I with the smallest value of κel being ca. 10-3 and the largest approaching unity.Simple models are proposed which account for the variations in κel based on the perturbational effects of ligand to metal charge transfer and triplet ligand field excited states on the electron exchange integral coupling reactants and products.
Magnetodynamic effects on outer-sphere electron-transfer reactions: A paramagnetic transition state
Ronco,Ferraudi
, p. 3961 - 3967 (2008/10/08)
The effect of the magnetic field on the rate of outer-sphere electron-transfer reactions has been investigated as a function of the field intensity, between 0 and 9 T, and at a given temperature. In complexes of d6 metal ions, i.e., Ru(II) and Co(III), the rate constant exhibits a complex dependence on the field: a complexity associated with field-induced changes of the electronic matrix element and the activation energy. Changes in the activation energy have been investigated as a function of the temperature at a given field intensity. These measurements have shown that the magnetic susceptibility of activation has the large positive values that are expected for a strongly paramagnetic transition state. The magnetic field effects are discussed in terms of symmetry-determined selection rules for the coupling of the initial and final electronic states of the reactions.
