Controlled Synthesis, Chiral Assembly, and Circularly Polarized Luminescence of Poly(Phenyl Isocyanide)‐Block‐Polyfluorene Copolymers

• Published in: Macromolecular rapid communications. Vol. 44; no. 15; pp. e2300159 - n/a
• Main Authors: Zou, Hui, Han, Shan‐Shan, Li, Guo‐Qiang, Zhou, Li, Liu, Na, Wu, Zong‐Quan
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2023
• Subjects: Alkynes; Block copolymers; chiral assembly; Chirality; Circular polarization; circularly polarized luminescence; Conformation; conjugated polymers; Copolymers; Cross coupling; Cyanides - chemistry; helical polymers; Luminescence; Molecular Conformation; Monomers; Nanofibers; Optical activity; Optical properties; Polymerization; Polymers - chemistry; Segments; Self-assembly; chiral assembly; circularly polarized luminescence; helical polymers; conjugated polymers
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.202300159

In this work, π‐conjugated block copolymers consisting of poly(phenyl isocyanide) (PPI) and polyfluorene (PF) segments are facilely prepared by one‐pot sequential polymerization of phenyl isocyanide (monomer 1) and 7‐bromo‐9,9‐dioctylfluorene‐2‐boronic acid pinacol ester (monomer 2). The Pd(II)‐terminated PPI is first prepared via polymerizing monomer 1 catalyzed with phenyl alkyne‐Pd(II) complex and then utilized to initiate the controlled Suzuki cross‐coupling polymerization of monomer 2, yielding various PPI‐b‐PF copolymers possessing controlled molar mass and narrow dispersity. Owing to the helical conformation of PPI segment and π‐conjugated structure of PF segment, PPI‐b‐PF copolymers present distinctive optical property and fascinating chiral self‐assembly behavior. During the self‐assembly process, chirality transfer from helical PPI block to the supramolecular aggregates of helical nanofibers occurs to afford optically active helical nanofibers with high optical activity. Furthermore, the self‐assembled helical nanofibers exhibit excellent circularly polarized luminescence performance. Optically active π‐conjugated poly(phenyl isocyanide)‐block‐polyfluorene copolymers with controlled molar mass and narrow dispersity are facilely prepared. The obtained copolymers can self‐assemble into helical nanofibers with high optical activity, and the helical direction of the helical nanofibers depends on the helical control of the poly(phenyl isocyanide) block. Moreover, the self‐assemblies of poly(phenyl isocyanide)‐block‐polyfluorene copolymers present excellent circularly polarized luminescence performance.