Organo-catalyzed polycyclotrimerization of bis(aroylacetylene)s: A facile strategy toward regioregular hyperbranched poly(aroylarylene)s

Alkyne polycyclotrimerization has emerged as a versatile synthetic platform for the preparation of hyperbranched polyphenylenes. However, most existing systems rely on transition metal catalysts, suffer from harsh reaction conditions, and yield regioirregular polymers, which limit their practical applicability. Herein, we present a facile and efficient strategy for the synthesis of regioregular hyperbranched polymers via organocatalyzed polycyclotrimerization of activated terminal diynes. Specifically, the polymerization reactions of bis(aroylacetylene)s were conducted in dichloromethane (DCM) at 30 °C for 5 h in the presence of 4-dimethylaminopyridine (DMAP) and acetylacetone, affording five soluble hyperbranched poly(aroylarylene)s ( hb -PAAs) with high weight-average molecular weights of up to 1251000 g/mol in high yields of up to 90.7%. Notably, the polycyclotrimerization proceeds smoothly under open-air conditions without the need for moisture or oxygen exclusion. The hb -PAAs possess perfect 1,3,5-regiostructures, and high thermal stabilities with 5% weight loss temperatures up to 482 °C. The hb -PAA incorporating tetraarylethylene (TAE) moieties exhibits distinct aggregation-induced emission (AIE) characteristics. Furthermore, when doped into a poly(vinyl alcohol) (PVA) matrix, the polymers display room-temperature phosphorescence (RTP) properties, with phosphorescence lifetimes of up to 320 ms and phosphorescence quantum yields ( Φ p ) of up to 4.8%. This organocatalytic polycyclotrimerization provides a mild, metal-free route to regioregular hyperbranched polymers with tailored photophysical properties, showing great potential for advanced optoelectronic applications.