TRANSFER OF SOME ALKYL SUBSTITUTED FERROCENES FROM WATER TO CATIONIC SURFACTANT MICELLES STUDIED BY KINETIC METHOD

Binding of ferrocene and its 1,1'-dimethyl and n-butyl derivatives to dodecyl and tetradecyltrimethylammonium nitrate micellar aggregates has been studied at 20.0-degrees-C and ionic strength 0.02 mol dm-3 by examining the micellar retarding effects on the rates of iron(III) oxidation of these substrates. Solubilization of the ferrocenes in the cationic micellar phase increases as the substrate hydrophobic character increases and, to a lesser extent, as the surfactant hydrocarbon chain length becomes longer. The critical micelle concentrations of the surfactants used and the incremental free energy of transfer of methylene groups of both the substrate and the surfactant from the aqueous to the micellar pseudophase have also been determined. The present data are discussed and compared with those obtained previously in the presence of the longer homologous hexadecyltrimethylammonium nitrate and of some nonionic C(i)E(j) surfactants, providing evidence for the incorporation of the ferrocene solubilizates into the hydrophobic core of the micelle. (C) 1994 Academic Press, Inc.