Synthesis and Solid-State Polymerization of Novel Diacetylenes for Nonlinear Optics

Abstract
Novel unsymmetrical diacetylenes having a carbazolyl group directly bound to acetylene moiety, i.e. 1-(N-carbazolyl)-penta-1,3-diyne-5-ol(CPDO) and the derivatives were synthesized. These diacetylenes can be topochemically polymerized in the solid state and the absorption edges of the polymers are expanded to near infrared, suggesting that π-conjugation of the main chain becomes longer by the electrons donated from carbazolyl groups. From the action spectrum of photocurrent, the band gap energy of poly-CPDO was evaluated to be 1.6 eV, which is smaller than those of so-far-known polydiacetylenes. The ionization potential was estimated to be 4.4 eV.