Molecular Design of Naphthalene‐ and Carbazole‐Based Monomers for Regiospecific Synthesis of Poly(arylenevinylene)s via Co‐Catalyzed Hydroarylation Polyaddition

Abstract

AbstractThis study focuses on the development of regiospecific hydroarylation polyaddition of naphthalene‐ and carbazole‐based monomers with diynes under mild reaction conditions at room temperature. A 1‐pyrazole substituent serves as an appropriate directing group for a Co‐catalyst to efficiently activate the C–H bonds of generally inactive six‐membered aromatic hydrocarbons. The 1‐pyrazole groups in 2,6‐di(1‐pyrazolyl)naphthalene adopt planar conformations and act as directing groups, resulting in a smooth hydroarylation reaction. In contrast, the reaction with 1,5‐di(1‐pyrazolyl)naphthalene do not proceed. The polyaddition reaction of 2,6‐di(1‐pyrazolyl)naphthalene selectively proceeds at 3,7‐positions under mild reaction conditions at 30 °C, and yields corresponding poly(arylenevinylene) (PAV) with high molecular weight. This molecular design is also applicable to the hydroarylation polyaddition of carbazole; the polyaddition reaction of 9‐(2‐ethylhexyl)‐3,6‐di(1‐pyrazolyl)carbazole selectively occurred at 2,7‐positions. The optical and electronic properties of the synthesized compounds are evaluated. The obtained PAVs serve as an emitting material in organic light‐emitting diode (OLED). This study aims to develop a Co‐catalyzed hydroarylation polyaddition via C–H activation of generally inactive polyaromatic hydrocarbons (PAHs) under mild conditions.