Organoselenium-substituted poly(p-phenylenevinylene)

A new type of conjugated polymer, organoselenium substituted poly (p-phenylenevinylene) (PPV), was synthesized from the corresponding alkylselenenyl p-xylylene dibromide via a Gilch route using potassium tert-butoxide in THF The p-xylylene dibromide precursors were synthesized by reacting lithiated bis(methoxymethyl)benzenes with elemental selenium, followed by alkylation of the generated selenolates. As a final demasking step, the bromomethyl functions were liberated by ether cleavage using boron tribromide. Bis-alkylselenenyl PPV was obtained with an average molecular weight M. of approximately 300,000 g/mol and with polydispersity M-w/M-n = 2. Due to low solubility, monoalkylselenenyl PPV was obtained with a considerably lower average molecular weight in the proximity of 16,000 g/mol and with a polydispersity slightly larger than 3. Absorption and fluorescence spectroscopy revealed that the bis-alkylselenenyl PPV is extensively conjugated. (c) 2005 Wiley Periodicals, Inc.