EFFECTS OF ACCEPTOR STRUCTURE ON CHARGE-TRANSFER COMPLEXATION IN AQUEOUS POLYELECTROLYTE SOLUTION

Charge-transfer (CT) complexation between 1-pyrenesulfonate (PyS(-)) ( donor) and 9,10-anthraquinone-1-sulfonate (1-AQS(-)) (acceptor), and b etween PyS(-) and 9,10-anthraquinone-2-sulfonate (2-AQS(-)) (acceptor) in the solution of poly(1,1-dimethyl-3,5-dimethylenepiperidinium chlo ride) (PDDP+Cl-) was investigated by absorption spectroscopy, viscosit y and solubility measurements, and molecular orbital calculation. New broad UV bands corresponding to CT complexation between PyS(-) and 1- or 2-AQS(-) were observed only when the polycation was present in the system. A continuous variation method for both systems showed the stoi chiometries of the CT complexes were both 1:I in donor:acceptor compos ition. Reduced viscosity measurements showed to eta(sp)/c of PDDP+Cl- in Na(+)PyS(-)/Na(+)2-AQS(-) solutions decrease more rapidly than in N a(+)PyS(-)/Na(+)1-AQS(-) solutions as the salt concentration increase. Solubility measurements suggested that the polymer precipitated more easily in Na(+)PyS(-)/Na(+)2-AQS(-) than in Na(+)PyS(-)/Na(+)1-AQS(-) solution. These results suggest that interactions between the polycati on and the CT complex for Na(+)PyS(-)/Na(+)2-AQS(-) are stronger than that for Na(+)PyS(-)/Na(+)1-AQS(-). Plausible structures of the CT com plexes are discussed on the basis of the HOMO and LUMO energies and mo lecular orbital symmetry obtained by the MOPAC semi-empirical molecula r orbital calculation program.