Concentration and Solvent Sensitive Visible Spectra of Poly(tricyanovinyldimethylaniline): Aggregation and Solvatochromism

Abstract

This work presents unusual spectral behavior of poly(tricyanovinyldimethylaniline) (1) in dilute solutions. A new conjugated polymer(1) was prepared from p-(tricyanovinyl)N,N-dimethylaniline via the use of a methylglucopyranoside reagent. It is observed that dilute solutions of 1 exhibit spectral features associated with aggregation. The associative interaction is studied by changing the salt concentration of LiBr in DMF solution, by changing the concentration of 1, and by varying the solvents. The association modi®es the visible spectrum of 1 in dilute solution. Spectra of 1 in DMF solution exhibit an intense absorption maximum at 429 nm, which can be assigned to the side group, with tailing past 700 nm. With increasing concentration, a new absorption band arises between 480 nm and 700 nm. LiBr dissociates the aggregate to decrease the additional spectral features. The visible spectrum of 1 varies in dierent solvents. The spectrum of 1 in chloroform solution exhibits two maxima at 490 nm and 550 nm. The associative interaction presumably arises from a dipoleÀdipole interaction among pendant side groups. In DMF solution of 1 in the presence of p-chloranil, the spectrum shows a Downloaded by [University of California, San Francisco] at 22:23 26 December 2014 maximum at 429 nm with a distinct shoulder near 520 nm which does not orginate from 1 and p-chloranil(CA) itself.