Dye-substituted acetylenes and diacetylenes: Convenient polymerization as studied by differential scanning calorimetry, FT-IR, and UV-vis spectroscopy

A series of phthalimide- and 1,12-benzoperylene-1',2'-dicarboxylic imido-li nked alkynes were prepared and analyzed by UV, FT-IR, optical microscopy, a nd differential scanning calorimetry. The possibility to convert omega-alky nes (R-(CH2)(n)-C=CH) to diacetylenic compounds (R-(CH2)(n)C=C-C=C-(CH2)(n) -R) was investigated for R = phthalimide and 1,12-benzoperylene-1',2'-dicar boxylic imide with n = 1, 3, and 9. Formation of the diacetylenic compound is usually straightforward las checked by comparison with independently syn thesized diacetylenes), and in some cases heat-induced polymerization of th e thus-formed diacetylenes proceeds directly. For the perylene imide-linked materials with n = 1 and n = 3 1,a-polymerization occurs, while for n = 9 1,4-polymerization occurs. The 1,4-polymerization is also observed for the phthalimide-linked materials. For R = phthalimide and n = 1 this 1,4-polyme rization can only be induced by further heating, while for the analogous n = 9 compound 1,4-polymerization is already induced by UV-vis irradiation at room temperature. This is related to the flexibility of the methylene spac er in the crystal.