Conjugated materials: Problems and prospects for synthesis using carbohydrate reagents

General considerations related to the use of sugars and closely related compounds as reagents for molecular and macromolecular synthesis are presented. For the first time, we have used unprotected carbohydrates to initiate polymerizations. A variety of dicyanoalkenes and -arenes react with sugars in the presence of alkali to give conjugated polymers. Both cyclopolymerization and polymerization at only one of two cyano groups are observed, and some qualitative mechanistic issues related to these observations are discussed. In some cases, a sugar alkoxide is the active initiating reagent. Characterization of the resulting polymers is reported. Alkaline sugar reagents have also been used in Knoevenagel reactions to synthesize CN-PPV oligomers and a related conjugated polymer in good yields. The use of the polysaccharide chitosan as a polycation allows the absorption spectrum of the polythiophene HPURET to shift to longer wavelengths than other polycations in electrostatically assembled films.