Polycondensation of Bis(cyanoacetate) and a,10bDihydrobenzofuro2,3-bbenzofuran-2.9-dicarbaldehyde via Knoevenagel Reaction: Synthesis of Donor-Acceptor Polymers Containing Shoulder-to-Shoulder Main Chains

摘要

Compound 5a,10b-dihydrobenzofuro2,3-b benzofuran-2,9-dicarbaldehyde (II) was prepared by two-step reactions from p-cresol and glyoxa.The bis(cyanoacetate) monomers (III) were prepared in a high yield by reacting ethyl cyanoacetate with the appropriate diol in the presence of tetra-n-butyl titanate.The polymers from II and III were synthesized by Knoevenagel polycondensation that was first carried out in anhydrous THF and followed by a solid-state polycondensation,and main-chain polymers with good glass transition temperatures in high yield were obtained.The polymerization of II and III afforded polymers IV,which exhibited good solubility in most organic solvents.The structure of all the monomers and polymers were characterized by conventional spectroscopic methods.The synthesized polymers contain acceptor groups (cyanide and carbonyl) and a donor group (benzodihydrofuran) in their main chain.