Water Stable Boronic Acid Grafted Barium Metal-Organic Framework for the Selective Adsorption of cis-Diols.

Boronic acid groups have a high affinity toward cis-diols, which, when suspended in a metal-organic framework, generate a novel adsorbent for cis-diols. In this work, we followed a metal-ligand-fragment-coassembly (MLFC) approach to develop a series of water-stable barium metal-organic frameworks with uniform distribution of free boronic acid in the scaffold. The 11B nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopic (XPS) investigations show the enhancement in the inclusion as the feed amount of boronic acid moiety increases. The findings of the adsorption studies elucidated the importance of furanose isomeric form of cis-diols in determining the adsorption efficiency. Galactose is the favorable adsorbate which has the maximum number of molecules in its furanose isomeric form (∼7%). The developed MOFs are promising candidates for the isolation of cis-diols from aqueous solutions.