Synthesis and characterization of polybinaphthalene incorporating chiral ( R) or ( S)-1,1′-binaphthalene and oxadiazole units by Heck reaction

Abstract

Chiral conjugated polymers P-1 and P-2 were synthesized by the polymerization of ( R)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthalene (( R )- M-1) and ( S)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthalene (( S )- M-1) with 2,5-bis(4-vinylphenyl)-1,3,4-oxadiazole ( M-2) under Pd-catalyzed Heck coupling reaction, respectively. Both monomers and polymers were analysed by NMR, MS, FT-IR, UV, DSC-TG, fluorescent spectroscopy, GPC and CD spectra. The chiral conjugated polymers exhibit strong Cotton effect in their circular dichroism (CD) spectra indicating a high rigidity of polymer backbone. CD spectra of polymers P-1 and P-2 are almost identical and have opposite signs for their position. These polymers have strong blue fluorescence.