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-linked alkynes were prepared and analyzed by UV, FT-IR, optical microscopy, and differential scanning calorimetry. The possibility to convert ω-alkynes (R−(CH2)n−C⋮CH) to diacetylenic compounds (R−(CH2)nC⋮C−C⋮C−(CH2)n−R) was investigated for R = phthalimide and 1,12-benzoperylene-1‘,2‘-dicarboxylic imide with n = 1, 3, and 9. Formation of the diacetylenic compound is usually straightforward (as checked by comparison with independently synthesized diacetylenes), and in some cases heat-induced polymerization of the thus-formed diacetylenes proceeds directly. For the perylene imide-linked materials with n = 1 and n = 3 1,2-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-polymerization 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 spacer in the crystal.