Synthesis of poly(arylenevinylene)s containing 1,5- or 9,10-anthrylene moieties and their optical and electrochemical properties

Alternating copolymers containing anthrylenevinylene and phenylenevinylene were synthesized by Wittig condensation reaction. The molecular weight of polymers was very low possibly due to the low solubility of anthracene dicarbaldehyde and the resulting polymers. The absorption spectrum of polymer containing 1,5 position-linked anthrylene showed slightly longer absorption maximum wavelength and smaller optical band gap in comparison with polymer containing 9,10 position-linked anthrylene due to longer conjugation length. The electrochemical band gap of polymer containing 1,5 position-linked anthrylene was smaller which is consistent with the results from its optical band gap. The solution and solid-state emission maximum of polymer containing 9,10 position-linked anthrylene exhibited longer wavelength and large Stokes shift due to the more quinoidal form in excited state and the significant difference in the conformation between ground state and excited state. Polymer containing 1,5 position-linked anthrylene showed very high photoluminescence quantum yield due to the zigzag structure of polymer backbone that weakens the interchain interaction and the rotational relaxation hence reduces the non-radiative pathway.