Charge-Transfer Complexation in Aqueous Polyelectrolyte Solution. I. Complexation between Dimethoxyanthracenesulfonate Ion and Anthraquinonesulfonate Ion.

Absorption and fluorescence spectroscopic studies on the charge-transfer (CT) complexation between 9,10-dimethoxyanthracene-2-sulfonate ion (DMACS−) and 9,10-anthraquinone-2-sulfonate ion (AQS−) in aqueous solution were performed in the presence of poly(allylammonium chloride) (PAAH+Cl−), as well as in its absence. No spectroscopic indication of the CT complex was recognized by mixing Na+DMACS− (1 × 10−4 M) with Na+AQS− (1 × 10−4 M), but the addition of PAAH+Cl− to the mixed solution brought about the CT complexation. On the other hand, in the absence of PAAH+Cl−, DMACS− and AQS− also form the CT complex when their concentrations become ca. 1 × 10−3 M. Therefore, the CT complexation between DMACS− and AQS− in PAAH+Cl− solution can be attributed to a close proximity of DMACS−–AQS− pairs, which results from the electrostatic binding of them by the polyions. The continuous variation method for the CT band indicated that a 1 : 2 (DMACS− : AQS−) complex and a 1 : 1 complex were preferentially formed in the pre...