Precise Synthesis of Optically Active and Thermo-degradable Poly(trifluoromethyl methylene) with Circularly Polarized Luminescence

Developing high performance and environment-friendly fluoropolymers is greatly desired. In this work, we found that 2-diazo-1,1,1-trifluoroethane can be polymerized by air-stable alkyne-palladium(II) catalysts following a living polymerization mechanism, affording a fluoropolymer, poly(trifluoromethyl methylene) in high yield with controlled molar mass and low dispersity. This polymer bears trifluoromethyl on every main chain atom and thus has good resistance to chemical corrosion, high hydrophobicity, and excellent dielectric constant with low dielectric loss. Due to the steric hindrance between the trifluoromethyl pendants, the synthetic poly(trifluoromethyl methylene) can twist into a stable helix. The one-handed preferred helices synthesized using chiral Pd-II-catalysts exhibit high optical activity and circularly polarized luminescence. Remarkably, such polymer can be completely degraded to (E)-1,1,1,4,4,4-hexafluorobut-2-ene at high temperatures (>280 degrees C). Additionally, taking advantage of the living chain end, the polymer can be further modified.

Automated summary

This work demonstrates the development of high performance fluoropolymers through a living polymerization mechanism. The synthesized poly(trifluoromethyl methylene) exhibits excellent properties such as resistance to chemical corrosion, high hydrophobicity, and low dielectric loss. The polymer can form stable helices and shows high optical activity and circularly polarized luminescence when synthesized using chiral palladium catalysts. Moreover, the polymer can be completely degraded to (E)-1,1,1,4,4,4-hexafluorobut-2-ene at high temperatures (>280 degrees C) and can be further modified.