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Three alternating poly(m-p-anilines) are synthesized via palladium-catalyzed amination reactions and polymers are oxidized to radical cations by the use of chemical and electrochemical methods. The presence of radical cations is demonstrated by the appearance of two bands in UV-vis spectra, the positions of which depend on chemical structure of polymers.

Poly(3,3'-dioctyl-2,2':5',2'-terthiophene) is fabricated into five fractions distinctly differing in their molecular weights in order to determine the influence of the degree of polymerization (D[P.sub.n]) on its principal physicochemical parameters. The results have shown that at least in the polythiophene family of electroactive parameters, the DP dependence of the crucial electrical parameters persists to relatively high molecular weights and have indicated the importance of the macromolecular parameters control in the fabrication of polymer-based electronic and electrochemical devices.

Vibrational dynamics in triarylaminedendrimers was studied ina complementary way by Raman and infrared (IR) spectroscopies andincoherent inelastic neutron scattering (IINS). Three molecules wereinvestigated, namely, unsubstituted triarylamine dendrimer of thefirst generation and two dendrimers of the first and second generation,substituted in the crown with butyl groups. To facilitate the assignmentof the observed IR and Raman modes as well as the IINS peaks, vibrationalmodels, based on the general valence force field method (GVFF), werecalculated for all three compounds studied. A perfect consistencybetween the calculated and experimental results was found. Moreover,an important complementarity of the vibrational spectroscopies andIINS was established for the investigated dendrimers. The IINS peaksoriginating mainly from the C–H motions were not restrictedby particular selection rules and only dependent on the IINS crosssection. To the contrary, Raman and IR bands were imposed by the selectionrules and the local geometry of the dendrimers yielding mainly C–Cand C–N deformation modes with those of C–H nature ofmuch lower intensity. Raman spectroscopy was also applied to the studiesof the oxidation of dendrimers to their cationic forms. A strong Ramanresonance effect was observed, since the spectra of the studied compounds,registered at different levels of their oxidation, strongly dependedon the position of the excitation line with respect to their electronicspectrum. In particular, the blue (458 nm) excitation line turnedout to be insensitive toward the cationic forms yielding very limitedspectral information. To the contrary, the use of the red (647 nm)and infrared (1064 nm) excitation lines allowed for an unambiguousmonitoring of the spectral changes in dendrimers oxidized to nominallymonocationic and tricationic states. The analysis of oxidation-inducedspectral changes in the tricationic state indicated that the chargestorage configuration predominantly involved one spinless dicationof the quinoid bond sequence and one radical cation. However, smallnumbers of dications were also found in a nominally monocationic state,where only radical cations should have been present. This findingwas indicative of some inhomogeneity of the oxidation. [ABSTRACT FROM AUTHOR]