Hyperbranched Poly(aryleneethynylene)s: Synthesis, Thermal Stability and Optical Properties

Abstract Summary: Alkyne copolycyclomerizations of aromatic diynes 2,7‐bis(4‐ethynylphenylethynyl)‐9,9‐dihexylfluorene ( I ) and 1,4‐bis(4‐ethynylphenylethynyl)benzene ( II ) with an aliphatic monoyne 1‐dodecyne ( A ) were effected by CpCo(CO) 2  hv in THF, producing hyperbranched poly(aryleneethynylene)s ( 1 and 2 ) of high molecular weights ( $\overline M _{\rm w}$ up to 4.4 × 10 4 Da) in high isolation yields (up to 97%). The polymers possessed outstanding thermal stability and emitted strong deep blue light of ≈400 nm when their solutions were photoexcited. The polymers effectively limited the light of a 532 nm laser, with the performance of 2 being better than that of C 60 , a well‐known optical limiter, under similar linear transmittance. The structure of hyperbranched poly(aryleneethynylene). image The structure of hyperbranched poly(aryleneethynylene).