Synthesis, Light Emission, Explosive Detection, Fluorescent Photopatterning, and Optical Limiting of Disubstituted Polyacetylenes Carrying Tetraphenylethene Luminogens

Tetraphenylethene-functionalized acetylenes [(C6H5)2CC­(C6H5)­(C6H4CCR), R = C8H17 and C6H5] were synthesized, and their polymerizations were effected by WCl6–Ph4Sn at elevated temperatures in toluene under nitrogen, furnishing polymers P1 and P2. The polymers possessed good solubility and degraded at high temperatures of up to ∼400 °C under nitrogen. Both polymers emitted weakly in the solution state. Whereas the emission of P1 was enhanced when aggregated, that of P2 was quenched, demonstrating that the light emission of polyacetylenes could be varied readily by changing their molecular structure. The polymers could serve as fluorescent chemosensors for explosive detection with an amplification effect. UV irradiation of their films in air photo-oxidized and bleached the fluorescence of the exposed parts, generating fluorescent photopatterns. The polymers exhibited optical nonlinearity and could limit laser pulses.