Room-temperature Barbier single-atom polymerization induced emission as a versatile approach for the utilization of monofunctional carboxylic acid resources

Abstract

Carboxylic acids are widely available from both biomass and fossil sources on the Earth. In comparison with multifunctional carboxylic acid containing chemicals that have been comprehensively used as building blocks of polymer materials, monofunctional carboxylic acid resources exhibit broader availability but are rarely utilized as monomers for polymerization, attributed to their monofunctionality. Here, we demonstrate a Barbier single-atom polymerization (SAP) as a versatile approach for the utilization of monofunctional carboxylic acid resources, where they act as a carbon source to contribute only one carbon atom for the construction of the polymer main chain. The key point for the polymerization of the monofunctional carboxylic acid resource is to difunctionalize it, which is realized through two Barbier additions between bifunctional aromatic halides and monofunctional peroxyester in the presence of Mg. Prior to the Barbier SAP, monofunctional phenylcarboxylic acid is converted into dibenzoyl peroxide (BPO) with higher reactivity. Through the Barbier SAP of BPO at room temperature, a series of nonconjugated polytriphenylmethanols (PTPMs) were prepared as polymerization-induced emission luminogens (PIEgens) with structure-specific nonconjugated luminescence including aggregation-caused quenching (ACQ) and aggregation induced emission (AIE) characteristics, where starting monomers and repeating units are nonemissive. Further applications of PIEgens were carried out for an artificial light-harvesting system with an antenna effect of over 18.5 and explosive detection at the ppm level in solution and ng level on test paper. This work therefore opens a new avenue for the design of nonconjugated luminescence by utilizing Earth's monofunctional carboxylic acid resources sufficiently.