Fig. 4: B-aPOPs with unprotected trivalent B-center.

a Synthesis of B-P9a,b, B-P10a,b, B-P11a,b and B-P12a,b by B-Sn exchange reaction³⁹. b, c Pyridine and trimethylamine sensing of B-P9b in the solid state. d Pyridine adsorption and solid-state ¹¹B NMR spectra of B-P9b. (adapted with permission from ref. ³⁹. © 2022 American Chemical Society).