Synthesis of novel optically active poly(phenyleneethynylene- aryleneethynylene)s bearing hydroxy groups. Examination of the chiroptical properties and conjugation length

摘要

Novel optically active poly(phenyleneethynylene-aryleneethynylene)s bearing hydroxy groups with various arylene units [poly(1-2), poly(1-3a), poly(1-3b), poly(1-4)] were synthesized by the Sonogashira-Hagihara coupling polymerization of (S)-3,5-diiodo-4-hydroxy-C6H4CONHCH(CH 3)COOC12H25 (1) with HC? -C-Ar-C? -CH [2 (Ar = 1,4-phenylene), 3a (Ar = 2,7-naphthylene), 3b (Ar = 1,4-naphthylene) and 4 (Ar = 1,6-pyrenylene), and the optical properties were compared. Polymers with number-average molecular weights (M_n) of 5,300-11,300 were obtained in 88-94% yields. CD and UV-vis spectroscopic analysis revealed that all the polymers formed predominantly one-handed helical structures in THF. The order of absorption maxima (λ_(max)) of the polymers was poly(1-3a) < poly(1-2) < poly(1-3b) < poly(1-4). Poly(1-2), poly(1-3a), poly(1-3b), and poly(1-4) emitted blue, purplish blue, green and yellow fluorescence, respectively.