Poly(o-toluidine) as the matrix for incorporation of palladium species from PdCl2 aqueous solutions

Reactivity of poly(o-toluidine) in the emeraldine base form (POT) and protonated with HCl (POT/HCl) in PdCl2 aqueous solutions of various HCl concentrations has been studied. Using elemental analysis, FTIR, UV-Vis, XPS and EXAFS spectroscopies as well as XRD and SEM it has been established that POT/HCl is more reactive than POT. The course of reactions is influenced by the type of the PdCl2 solution. Thus, protonation of POT with incorporation of palladium (11) chloro-and/or aquachloro -and/or chlorohydroxycomplexes counterions is the main process occurring in the PdCl2 Solutions of higher HCl concentration. A redox reaction resulting in the oxidation of the polymer chain with simultaneous formation of metallic palladium takes place in the PdCl2 solution of lower HCl concentration. POT/HCl shows enhanced reducing properties with respect to POT. Lowering of the protonation level (i.e. some deprotonation) of POT/HCl has been also observed. Coordination of palladium (11) ions by nitrogen atoms of the polymer chain can be also postulated. (C) 2003 Elsevier Ltd. All rights reserved.