ENHANCEMENT OF CHARGE-TRANSFER COMPLEX-FORMATION BETWEEN 1,4-DIMETHYL-NAPHTHALENE AND P-CHLORANIL DURING THE SOL-GEL REACTION OF TETRAETHYLORTHOSILICATE

The absorption spectra of mixed solutions composed of 1,4-dimethyl-nap hthalene (DMN) and p-chloranil (pC) in tetraethyl orthosilicate disper sions during a sol-gel reaction catalyzed by HCl at room temperature h ave been observed as a function of time. Just after preparing the solu tion, the absorption band of the charge-transfer (CT) absorption at ar ound 535 nm due to the CT complex formation between pC and DMN was bar ely visible. As the sol-gel reaction proceeded, the intensity of the C T band increased with reaction time. This increase in the CT absorptio n band was highly enhanced after the gelation and stopped after ca. 10 0 days. (C) 1998 Elsevier Science B.V. All rights reserved.