A π‐Conjugated, Covalent Phosphinine Framework

Abstract

Abstract Structural modularity of polymer frameworks is a key advantage of covalent organic polymers, however, only C, N, O, Si, and S have found their way into their building blocks so far. Here, the toolbox available to polymer and materials chemists is expanded by one additional nonmetal, phosphorus. Starting with a building block that contains a λ 5 ‐phosphinine (C 5 P) moiety, a number of polymerization protocols are evaluated, finally obtaining a π‐conjugated, covalent phosphinine‐based framework (CPF‐1) through Suzuki–Miyaura coupling. CPF‐1 is a weakly porous polymer glass (72.4 m 2 g −1 BET at 77 K) with green fluorescence ( λ max =546 nm) and extremely high thermal stability. The polymer catalyzes hydrogen evolution from water under UV and visible light irradiation without the need for additional co‐catalyst at a rate of 33.3 μmol h −1 g −1 . These results demonstrate for the first time the incorporation of the phosphinine motif into a complex polymer framework. Phosphinine‐based frameworks show promising electronic and optical properties, which might spark future interest in their applications in light‐emitting devices and heterogeneous catalysis.