Synthesis and properties of amino acid-derived optically active photo-responsive polymers

Optically active azobenzenedicarboxylic acids were synthesized from l-alanine, and the polycondensation of the diacids with o-, m-, p-xylylenediols, 5-norbornene-2, 3-endo, endo- and exo, exo-dimethanols, m-, p-xylylenediamines, and trans-1, 4-cyclohexanediamine was carried in N, N-dimethylformamide. Polymers with weight-average molecular weights of 3, 300–33, 700 were obtained in 63%-quantitative yields. All the polymers reversibly isomerized the azobenzene units from trans to cis and vice versa upon UV- and visible-light irradiations. The polymers exhibited no evidence for the formation of a chiral secondary structure

Synthesis of highly conjugated poly(3,9-carbazolyleneethynylenearylene)s emitting variously colored fluorescence

Novel conjugated polymers P1–P7 containing 3, 9-linked carbazole units in the main chain were synthesized by the polycondensation of 3-ethynyl-9-(4-ethynylphenyl)carbazole (EEPCz) and dihaloarenes, and their optical and electrical properties were studied. Polymers with weight-average molecular weights of 4100–48, 000 were obtained in 24–92% yields by the Sonogashira coupling polycondensation in tetrahydrofuran (THF)/Et3N at 30 or 50 °C for 48 h. All the polymers absorbed light around 350 nm. The polymers with electron-accepter units exhibited absorption bands originating from charge transfer. The polymers except the one containing azobenzenes emitted variously colored fluorescence with moderate quantum yields upon excitation at the absorption maxima. P1–P3 were oxidized around 0.6 V, and then reduced around 0.5 V. The conductivity of P3 was 1.1 × 10−14 S/cm at 103 V/cm