Valence bond configuration mixing

McLennan, D. J. Pross, A. The mechanism for nucleophilic substitution of a-carbonyl derivatives. Application of the valence-bond configuration mixing model./. Chem. Soc. Perkin Trans. 2 1984, 981-984. 

VALENCE BOND CONFIGURATION MIXING DIAGRAMS GENERAL FEATURES... 

VALENCE BOND CONFIGURATION MIXING DIAGRAM WITH IONIC INTERMEDIATE CURVES... 

Valence Bond Configuration Mixing Diagram for Proton-Transfer Processes... 

Insights from Valence Bond Configuration Mixing Diagrams One Electron Less-One Electron More... 

The trends in the activation barriers were explained440,442 using the valence bond configuration mixing model443 444, as shown schematically in Figure 32a. According to this... 

VBCM, see Valence bond configuration mixing theory... 

Unlike thiophene radical cation the SOMO for this species is 2bl with considerable spin density on sulfur. The reversible electrochemical oxidation potentials for 129 and some of its derivatives in l,l,l,3,3,3-hexafluoro-2-propanol are listed in Table 8. The reactions of 129 with radicals and with nucleophiles has been studied [275]. The position of attack by radicals on 129 should reflect the spin density at that position as found by EPR spectroscopic analysis. Indeed reaction with N02 occurs predominantly at S, C(2) and C(4) as expected. The valence bond configuration mixing model leads to the prediction that nucleophiles should preferentially attack 129 at C(l) and C(3) with little attack at S, C(2) and C(4). This is partly but not completely validated experimentally. Radi-... 

The discussion so far has considered only heterolytic processes for substitution reactions, but there is increasing evidence that substitutions may take place by a single electron shift synchronous with bond displacement or by a single electron transfer (SET) pathway in which electron transfer precedes bond displacement. To understand the basis of this theory, it is useful to discuss a conceptual model for organic reactions that has been called the valence bond configuration mixing (VBCM) model. As described by... 

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