Main Chain 1,5-Disubstituted-1H-Tetrazole-Based Polymers via Ugi-Azide-Four-Multicomponent Polymerization (UA-4MCP)

Abstract

The utilization of the distinctive molecular architecture of tetrazoles, which comprises a five-membered ring containing four nitrogen atoms, offers tremendous potential in the field of polymer chemistry. Although research on pendant chain tetrazolecontaining polymers has been considerably reported, the exploration of advanced synthesis methods for main chain tetrazole-based polymers has not been extensively undertaken. On this premise, the synthesis of main chain 1,5-disubstituted-1H-tetrazole (1,5-DS-T)-based compounds was investigated to showcase the possibility of polymer formation by using the Ugi-azide-four-multicomponent polymerization (UA-4MCP) strategy. Particularly, UA-4MC polymers were designed with various side groups (e.g., aliphatic or aromatic) and engineered for a post-polymerization modification via thiol-ene photo-click reaction. The chemical characterization confirmed 1,5-DS-T-based polymer formation with a number average molecular mass (M n ) up to 8500 g mol −1 . Importantly, side-group variation permitted tuning the glass-transition temperature (T g ) between −25 and 60 °C. Furthermore, the polymers exhibited moderate thermal stability up to 305 ± 10 °C besides interesting nonconventional fluorescence behavior.