Figure 1. Synthesis and characterization of COP-99.

(a) Proposed chemical structure of COP-99 along with its synthetic procedure. The obtained polymer was dark brown powder. (b) Powder X-ray diffraction pattern of COP-99. Inset displays scanning electron microscopy image of COP-99. Scale bar, 10 μm. (c) C 1s, (d) O 1s, and (e) F 1s XPS spectra of COP-99. (f) Solid-state ¹⁹F-NMR spectrum of COP-99. Black asterisks (*) indicate spinning side bands. (g) Argon adsorption–desorption isotherm of COP-99 measured at 87 K and (h) corresponding NLDFT pore size distribution.