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Structural consequences of electron transfer reactions. 8. Elucidation of isomerization mechanism of the radical anion of (η4-cyclooctatetraene)cyclopentadienylcobalt with FFT-Faradaic admittance measurements.
Autorzy
Rok wydania
1983
Czasopismo
Journal of the American Chemical Society
Numer woluminu
105
Strony
1772-1776
DOI
10.1021/ja00345a013
Kolekcja
Język
Angielski
Typ publikacji
Artykuł
The reduction of ( 4-1,5-cyclooctatetraene)cyclopentadienylcobalt, (l,5-COT)CoCp, proceeds in an apparently irreversible one-electron step to an isomerized anion, (l,3-COT)CoCp". The present study addressed the mechanistic question of whether the isomerization occurs concomitant with or subsequent to the electron-transfer step. Since the isomerization step was too fast to be studied by normal cyclic voltammetric or moderate frequency ac polarographic techniques, studies using Fast Fourier Transform Faradaic Admittance measurements were undertaken. Using ac frequencies up to 24 kHZ, the reduction was characterized as an EC process (isomerization reaction following the electron-transfer step) with a rate constant for the isomerization step (at 298 K) of (2 ± 1) X 103 s"1 in dimethylformamide containing 0.1 M Bu4NBF4 as supporting electrolyte. The heterogeneous electron-transfer rates of the reductions of both isomers were evaluated as ksapp = 0.28 cm/s for the 1,3-isomer and 0.06 cm/s for the 1,5-isomer.
Adres publiczny
http://dx.doi.org/10.1021/ja00345a013