New cyanopyridine‐based π‐conjugative poly(azomethine)s: Synthesis,characterization and electroluminescence studies

Four new Schiff‐base type conjugative polymers (CPs), that is, Py _1‐4 carrying a strong electron‐withdrawing cyanopyridine scaffold coupled with different electron‐donating aromatic/heteroaromatic moieties were synthesized from their respective co‐monomers by simple poly‐condensation route. They were subjected to structural, thermal, photophysical, and electrochemical characterizations and theoretical investigations in order to identify their suitability in polymer light‐emitting diode (PLED) application. All these polymers showed good film‐forming ability and exhibited favorable photophysical behaviors with an optical bandgap in the order of 2.54‐2.68 eV. Further, their electrochemical data were used to evaluate highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels. Finally, Py _1‐4 were successfully employed as blue‐light emitter in the construction of new ITO/PEDOT:PSS/ Py _1‐4 /Al configured light‐emitting diodes (LED), and the fabricated devices demonstrated stable blue electroluminescence behavior endorsing an effective electrons injection in the PLEDs.     

Crystal and molecular structure of the unreactive form of 1,8-bis (p-chlorophenyl)-octa-1,7-diene-3,5-diyne

The title compound (C₂₀ H ₁₂Cl₂,M _r =322, mp 69–70°C) crystallizes in the monoclinic system, space groupP2₁/n, witha=3.942(2),b=6.887(2),c=28.701(4) Å,=91.362(4)°,V _c =778.93(2) ų,Z=2,D _c =1.373,D _m =1.370(1) (in C₆H₆/CCl₄) g cm^–3,F(000)=332 and (MoK)=3.57 cm^–1. The final residuals areR=0.0365 andR _w =0.0368 for 999 observed reflections at the levelI3(I). The molecule as a whole is found to havetrans conformation. This structural study reveals that the title compound does not undergo solid-state polymerization due to close packing.