Catalyst-Free Four-Component Spiropolymerization for the Construction of Spirocopolymers with Tunable Photophysical Properties

Spiropolymers have gained a great deal of interest from both academic and industrial fields by virtue of their unique geometric structures and physical properties. Herein, we prepared a series of spirocopolymers through the catalyst-free four-component spiropolymerization of diisocyanides, activated alkynes, and two different kinds of monomers with reactive carbonyl groups. It is found that the polymerization reactivity of monomers, feeding modes, and feed ratios play significant roles in spirocopolymerization. Monomers with high reactivity and feeding reactive monomers first contribute to improving the molecular weights and yields of the polymers. The constructed copolymers have two different kinds of spiro structures, which is confirmed by the nuclear magnetic resonance. In addition, the spirocopolymers display the unique cluster-triggered emission and aggregation-induced emission properties, and their emission properties can be well-modulated by altering the ratio of comonomers. It is highly anticipated that this line of research will enrich the methodology of multi-component spiropolymerization, and provide a new insight into developing spiropolymers with various spiro structures and tunable properties.