Prearation and Nonlinear Optical Property of Polydiacetylenes from Unsymmetrical Diphenylbutadiynes with Trifluoromethyl Substituents

Abstract In order to obtain the polydiacetylenes having π-conjugation between polymer backbone and side chains, many of unsymmetrical diphenylbutadiyne derivatives with trifluoromethyl substituents on one of the phenyl rings have been synthesized. Among them, 1-(3-(methylamino) phenyl)-4-(3, 5-bis (trifluoromethyl)-phenyl) butadiyne (MADF) was found to be topochemically polymerized with complete conversion into the polymer single crystals. Spectroscopies and X-ray crystal structure analysis revealed that the π-conjugation of this polymer are more extended than those of the so-far prepared poly(diphenylbutadiyne)s, with smaller dihedral angles between π-conjugation planes of polymer backbone and phenyl rings. The extended π-conjugation was also confirmed by larger X(3) values.