Isolated-alkene-linked porous organic polymers (BIT-POPs): facile synthesis via ROMP and distinguishing overlapping signals in solid-state 13C NMR

Abstract

Porous organic polymers (POPs) are a class of promising materials for overcoming environmental and energy issues worldwide. However, their amorphous nature makes structural characterization in the solid state very challenging. In addition, developing facile synthesis methods and applications for POPs with novel structures remain urgent issues requiring improvement. In this work, novel porous organic polymers (named BIT-POPs) with isolated trans-alkene linkages were synthesized via cross-linking bis-norbornene via ring opening metathesis polymerization (ROMP) in an extremely mild and fast manner. Spectral editing approaches, such as ¹³C-CPMAS, ¹³C-CPPI, and ¹³C-CPNQS, relating to solid-state NMR were used to distinguish the overlapping NMR signals of insoluble BIT-POPs, and two-dimensional ¹H–¹³C HETCOR spectra were used. Also, BIT-POP-5 was added to a polysulfone matrix as a porous filler to form a mixed-matrix membrane, which showed a 126% increase in CO₂ permeability during gas separation.