The effects of the crosslinking position and degree of conjugation in perylene tetraanhydride bisimide microporous polymers on fluorescence sensing performance

Abstract

In this study, two fluorescence conjugated microporous polymers based on perylene tetraanhydride bisimide (DP₄A₀ and DP₄A₂) were prepared via Sonogashira–Hagihara cross-coupling polymerization for the efficient detection of o-nitrophenol (o-NP). They were well characterized via FT-IR, solid state ¹³C NMR, elemental analysis, and other material characterization techniques. The experiments proved that both CMPs possess high thermal and chemical stability and a porous nature with Brunauer–Emmett–Teller (BET) specific surface areas of 41.3 and 402.1 m² g⁻¹. Importantly, owing to signal amplification by the conjugated skeleton, DP₄A₀ and DP₄A₂ exhibit extremely high sensitivity to o-NP with K_sv values of 1.83 × 10⁴ and 1.69 × 10⁴ L mol⁻¹ and limits of detection of 5.73 × 10⁻⁹ and 7.36 × 10⁻⁹ mol L⁻¹, respectively. The sensing performance of DP₄A₀ and DP₄A₂ was dependent on the position of crosslinking points and crosslinking density. Finally, super amplified quenching was considered the electron transfer mechanism and hydrogen bond interactions were also present.