Tetraphenylethene-decorated functional polybenzoxazines: post-polymerization synthesis via benzoxazine–isocyanide chemistry and application in probing and catalyst fields

Abstract

Benzoxazines have been widely studied as thermosetting plastics; in contrast, scarce attention has been focused on their functionalization. In this effort, a series of tetraphenylethene (TPE)-decorated, functional polybenzoxazines were successfully constructed by post-polymerization of a main-chain type benzoxazine precursor (P1) via efficient benzoxazine–isocyanide chemistry (BIC) under mild conditions. The obtained polymers were characterized by FT-IR, ¹H NMR and size exclusion chromatography (SEC) analyses. The representative polymer, P2-2, exhibits typical aggregation-induced emission enhancement (AIEE) characteristics, and was applied as a fluorescent probe to detect nitro compounds in high-water fraction medium (f_w% = 90%). In addition, the residual isocyano (–NC) groups on the obtained polymer (P2-3) were utilized to bind with CuCl, and the resulting polymer/metal complex (P2-3-CuCl) can be applied as an efficient heterogeneous catalyst for an azide–alkyne cycloaddition reaction in air. This current work provides a simple and effective method for the functionalization of easily obtained polybenzoxazines to further expand their application scope.