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Issue 15, 1977
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Volumes of activation for dissociative (D) mechanisms: the substitution of pentacyanoferrate(II) complexes by various nucleophiles

Abstract

The dissociative step of a dissociative, or D, substitution mechanism exhibits a volume of activation, ΔV1, which is independent of the nature of the incoming nucleophile. For the reaction of [Fe(CN)5(3,5Me2-py)]3–(3,5Me2-py = 3,5-dimethylpyridine) with [CN], ΔV1= 20.5 ± 0.8 cm3 mol–1; with pyrazine, ΔV1= 21.2 ± 1.0 cm3 mol–1; and with imidazole, ΔV1= 20.3 ± 1.0 cm3 mol–1. For the reaction of [Fe(CN)5(3CN-py)]3–(3CN-py = 3-cyano-pyridine) with [CN], ΔV1= 20.6 ± 0.5 cm3 mol–1. These volumes of activation are shown to correspond to stretching of the Fe–N bond in the activated complex from 65 to 88% of the distance corresponding to complete dissociation of the leaving group from the [Fe(CN)5]3– moiety.

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Article type: Paper
DOI: 10.1039/DT9770001460
Citation: J. Chem. Soc., Dalton Trans., 1977,0, 1460-1466
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    Volumes of activation for dissociative (D) mechanisms: the substitution of pentacyanoferrate(II) complexes by various nucleophiles

    T. R. Sullivan, D. R. Stranks, J. Burgess and R. I. Haines, J. Chem. Soc., Dalton Trans., 1977, 0, 1460
    DOI: 10.1039/DT9770001460

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