75180-84-6Relevant articles and documents
Arene transition metal complexes in reactions with nucleophilic reagents XIX. Transannular substituent effects in arene-chromium and iron complexes
Litvak, V.V.,Kun, P. P.,Shteingarts, V. D.
, p. 219 - 234 (1988)
As a result of coordination of chlorobenzene derivatives with the (η-C6H6)Cr+ fragment, the rate of methoxydechlorination was found to increase 14 fold.The effects of the transannular substituent on the rate of methoxydechlorination of (η-C6H5Cl)(η-C6H5X)Cr+A- complexes (1) and on the dissociation constants of (η-C6H5CO2H)(η-C6H5X)Crn acids n = 0 (2), 1+ (3) has been studied.A strong effect of X in the above reaction series has been found, which is defined by the linear correlation equations using the ?p, ?0 and ?R constants for complexes 1, 2 and 3 respectively.The arene-chromium and -iron complexes show a general tendency to increase the mesomeric contribution to the transannular substituent effect with an increase in the electron deficiency in the framework transmitting this effect.Comparison of the effects of X in complexes 1, 2 and 3 leads to the conclusion that there is an intermediate-like transition state in the methoxyde-chlorination of complexes 1, apparently proceeding with intermediate formation of metallorganic analogues of Meisenheimer complexes.
