Synthesis of highly fluorescent and soluble 1,2,4-linking hyperbranched poly(arylenevinylene) featuring intramolecular energy funneling

Abstract

The synthesis and optical properties of a highly soluble (>200mg mL -1) and highly fluorescent (ΦF in film =0.64) 1,2,4-linking hyperbranched poly(arylenevinylene) (1,2,4-hb-PAV) prepared via Wittig reaction of A3 (biphenyl-tricarbaldehyde) and B2 (phosphonium salt) monomers is reported. The molecular weight of 1,2,4-hb-PAV can be precisely controlled by the amount of the base (NaOCH3) used In the polymerization. The absorption and photoluminescence (PL) spectra of 1,2,4-hb-PAV shows distinct red-shifts compared to conventional 1,3,5-linking hyperbranched poly(arylenevinylene) (1,3,5-hb-PAV), attributed to the extended π-conjugation along ortho- (1,2-) and para- (1,4-) links. The inherent energy gradient from the shorter branches to the longer conjugated stem In 1,2,4-hb-PAV enabled a characteristic energy funneling effect, which is absent In conventional hyperbranched polymer of 1,3,5-hb-PAV. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.