Mixed-valence complexes dynamics

One final point should be noted. Theoretical discussions of electron transfer processes have focused almost entirely on outer-sphere processes. When we have an inner-sphere mechanism, or sufficient electronic interaction in a dynamically trapped mixed-valence complex to produce a large separation between upper and lower potential surfaces, the usual weak-interaction approach has to be abandoned. Thus a detailed knowledge of a potential surface which is not describable as an intersection surface of perturbed harmonic surfaces, for example, is required. For this purpose, detailed calculations will be required. The theory of these processes will be linked more... 

The book Electrons in Chemical Reactions by L. Salem places electron transfer in a broad context ranging from basic wave mechanics to ion-solvent interactions. Sutin has reviewed theories of electron transfer with emphasis on nuclear, electronic, and frequency factors and Wong and Schatz have given a useful unified account of the dynamics of mixed-valence complexes using the vibronic coupling model. ... 

In spite of the abundant work on synthetic, thermodynamic, structural, and spectroscopic aspects of mixed-valence compounds, the dynamic solution behavior toward external redox reagents has not been much addressed. When such compounds are unsymmetrical and valence-localized, several problems arise when a fully reduced dinuclear complex reacts with an oxidant. Haim pioneered a systematic study performed with different systems reacting with a common two-electron oxidant, peroxydisulfate (126). A relevant example is given by reaction (35) ... 

In more elaborate studies, Kubiak and coworkers have established experimentally the existence of dynamic equilibrium mixtures containing charge-transfer isomers of mixed-valence ruthenium complexes within [ Ru3(p-0)-(p-CH3C00)6(12c1 0)(L ) ](p-BL)[ Ru3(p-0)(p-CH3C00)6( C 0)(L") ] by monitoring the v(CO) vibrations in the infrared (p-BL = unsymmetrical pyr-azine derivatives). The mixed-valence charge-transfer isomers differ in the... 

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