CONCENTRATION AND SOLVENT SENSITIVE VISIBLE SPECTRA OF POLY(TRICYANOVINYLDIMETHYLANILINE): AGGREGATION AND SOLVATOCHROMISM

ABSTRACT

This work presents unusual spectral behavior of poly(tricyanovinyl dimethylaniline) (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 modifies 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 different solvents. The spectrum of 1 in chloroform solution exhibits two maxima at 490 nm and 550 nm. The associative interaction presumably arises from a dipole–dipole interaction among pendant side groups. In DMF solution of 1 in the presence of p-chloranil, the spectrum shows a maximum at 429 nm with a distinct shoulder near 520 nm which does not orginate from 1 and p-chloranil(CA) itself.

Keywords:

• Aggregation
• Solvatochromism
• Poly(tricyanovinyl-dimethylaniline)
• Charge-transfer complexation

ACKNOWLEDGMENTS

This work was supported in part by the Petroleum Research Fund under Grants 33424-AC7 and 37138-AC1.