Synthesis of spiroborate-linked covalent organic frameworks (COFs) based on 1,3-diol borates

Abstract

We report the synthesis of two spiroborate-linked COFs, BSCOF-1 and BSCOF-2, which were characterized by PXRD, FT-IR, solid-state ¹¹B NMR, XPS, and N₂ sorption measurements. Both BSCOF-1 and BSCOF-2 displayed enhanced hydrolytic stability over that of COF-5. Density functional theory (DFT) calculations were performed to reveal the strong resilience in aqueous and acidic environments for BSCOF-1, indicating high energy barriers for hydrolysis of the 1,3-diol-boronic ester bonds. This study should provide a strategy for constructing stable boronate ester-linked COFs, opening avenues for their application under demanding conditions.