Synthesis of Novel Substituted Polyacetylenes and Design of Polymerization Catalysts

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The present study deals with design and synthesis of novel substituted polyacetylenes, characterization of the formed polymers, and development of their electrooptic functions. The results obtained are outlined below.1.Design and Synthesis of Novel Substituted Polyacetylenes. Phenylacetylenes having bulky ortho substituents such as perfluoro-n-hexyl and (trialkylsilyl) methyl groups were polymerized to provide novel high molecular weight polymers. As another type of monomers, diphenylacetylenes with N-carbazolyl and trimethylgermyl groups produced new polymers in the presence of TaCl_5-based catalysts. Further, heteroatom-containing polyacetylenes were obtained from 3- (N-carbazolyl) -1-propyne, 1-phenylthio-1-propyne, 1-butylthio-2-phenylacetylene, and so on.2.Basic Studies on the Structure and Properties of Substituted Polyacetylens. Visiblenear IR,time-resolved spectra of these polymers in photo-excited states were measured with time resolutions below 300 fs. As another study, UV photoelection spectra of more than 20 polymers were measured, and their ionization threshold energies were determined. These values corresponded with the lowest excitation energies.3.Studies on the Electrooptic Properties of Substituted Polyacetylenes. Electroluminescence devices (ITO/Polymer/Mg-In) were fabricated by using ring-substituted poly (diphenylacetylenes) and poly (1-phenyl-1-alkynes). Green and blue luminescences were observed from the devices. These polymers displayd also photoluminescence. As a study of nonlinear optical properties, third-order susceptibilities of 9-anthrylacetylene copolymers and poly (N-carbazolylacetylene) were measured to show values ca. 10-100 times as large as that of poly (phenylacetylene). These values could be correlated with the cutoff wavelengths in UV-visible spectroscopy.