Fp. Cavasino et al., REACTIVITY OF SOME SQUARE-PLANAR PALLADIUM(II) COMPLEXES IN AQUEOUS-SOLUTION AND IN HEPTANE-AOT-WATER MICROEMULSIONS, Journal of the Chemical Society. Faraday transactions, 90(2), 1994, pp. 311-314
Citations number
24
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
The substitution reactions at square-planar palladium(II) complexes {[
PdX(en)](2+), where X = 2,2'-bipyridine or 4,4'-dimethyl-2,2'-bipyridi
ne, en = ethylenediamine) with ethylenediamine or N,N-dimethylethylene
diamine have been studied at 25.0 degrees C in aqueous solution and in
heptane-AOT-water microemulsions with various molar ratios, [H2O]/[AO
T] = W, the AOT concentration being kept constant at 0.12 mol dm(-3).
The kinetic data, obtained by using both conventional and stopped-flow
spectrophotometric methods, show that the reaction rates, either in b
ulk aqueous solution or in the microemulsions, decrease with increasin
g steric hindrance of both the entering nucleophile and the ligand coo
rdinated to the metal. Moreover, the reaction rate in the microemulsio
ns is accelerated compared with that in the bulk aqueous solution and
exhibits a dependence on the molar ratio W. The microscopic AOT/water
interface is suggested as the reaction site.