No abstract

Benzobisthiazole polymers containing mono‐, bi‐, and terthiophene moieties were synthesized through polycondensation in polyphosphoric acid of 2,5‐diamino‐1,4‐benzenedithiol dihydrochloride with thiophene‐2,5‐dicarboxylic acid, 2,2′‐bithiophene‐5,5′‐dicarboxylic acid, and 2,2′:5′,2″‐terthlophene‐5,5″‐dicarboxylic acid, or their corresponding diacid chlorides, respectively. Intrinsic viscosities of up to 8.1 dL/g (methanesulfonic acid, 30°C) were recorded. Polymer structures were verified by elemental analysis and spectroscopic comparison of the polymers with appropriate model compounds. Onset of breakdown under thermogravimetric analysis in air occurred in the 460–590°C range with the benzobisthiazole polymers containing a monothiophene linkage being the most stable. Films suitable for third‐order optical susceptibility measurements could be prepared by extrusion techniques from the benzobisthiazole polymer containing a monothiophene linkage. Degenerate four wave mixing measurements on this film yielded a third order optical susceptibility χ(3) of approximately 4.5 × 10−10 esu. © 1993 John Wiley & Sons, Inc.

As part of a continuing study, a series of highly conjugated aromatic benzobisthiazole, benzobisoxazole, and N,N-diphenylbenzbisimidazole model compounds were synthesized, and their third-order nonlinear optical properties investigated by using subpicosecond degenerate four-wave mixing. Measurementa were made at 602 nm on THF solutions, vacuum-deposited films, or melt-quenched films. In all but one material, the third-order effect was determined to be instantaneous within the employed temporal resolution, suggesting dominance of electronic nonlinearity. From the experimental data it was possible to formulate structure-nonlinear optical property correlations and demonstrate that the molecular second hyperpolarizability can be increased almost 3 orders of magnitude by simple structural modifications. IX: #I= L4((NIylr + N~Y,,)~ + (N1yli)2)'/2 (15) Shand, M. L.; Chance, R. R. In Nonlinear Optical Propertiesof Organic and Polymeric Materiale; Williams, D. J., Ed.; ACS Symp. Ser. No. 233; American Chemical Society: Washington, DC, 1983.

The reactions of some ortho‐substituted anilines with various α,β‐acetylenic ketones were investigated as a route to 4‐alkyl‐, 4‐aryl‐, 4‐hydroxy‐, and 4‐amino‐3‐quinolyl ketones. The anilines examined were 2‐aminoacetophenone (1), 2‐aminobenzophenone (2), anthranilonitrile (3), methyl anthranilate (4), and ethyl anthranilate (5). The acetylenic ketones used were 1,4‐diphenyl‐2‐butyne‐1,4‐dione (6), 3‐butyn‐2‐one (7), 1,3‐diphenyl‐2‐propyn‐1‐one (8), and 4‐phenyl‐3‐butyn‐2‐one (9). The acetylenic ketones typically reacted with the anilines to give enamines; however, exceptions were found. Acetylene 6 reacts with 3 to give the enamine (13) along with a small amount of 2,3‐dibenzoyl‐4‐quinolamine (14). The reactions of 1 or 2 with 6 give the respective quinoline derivatives directly. Acetylene 8 reacts with 2 to give 3‐benzoyl‐2,4‐diphenylquinoline (22) directly, whereas no reaction occurs between 8 and 1 or 3. Acetylene 9 does not react with 1, 2, or 3. The enamines exist as the intramolecularly hydrogen bonded isomers and usually undergo cyclization with 5 molar equivalents of methanolic sodium methoxide to give quinoline derivatives. The 4‐quinolinols exist predominantly as the 4‐quinolinone tautomer.