Synthesis, Transformation, Catalysis, and Gas Sorption Investigations on the Bismuth Metal–Organic Framework CAU‐17

Abstract

Very few microporous bismuth metal‐organic frameworks have been discovered to date. Of these, no detailed experimental characterization of the synthesis and properties have been reported until now for the only one which can be prepared from inexpensive starting materials: CAU‐17 [Bi(BTC)(H 2 O)], with H 3 BTC = trimesic acid. In‐situ powder X‐ray diffraction during solvothermal synthesis of CAU‐17 revealed that it crystallizes rapidly within 2 minutes, and if the reaction is not stopped, the MOF transforms into a nonporous dense purely inorganic material within one hour, revealing that CAU‐17 is a crystalline intermediate phase. Synthesis scale‐up employing more concentrated reaction mixtures resulted in another Bi trimesate of composition [Bi(HBTC)(NO 3 )(MeOH)] · MeOH, which structurally decomposes upon storage under ambient conditions. Sorption experiments showed that CAU‐17 is microporous with a BET surface area of 530 m 2 /g. As a potential greenhouse gas sorbent, CAU‐17 showed high SF 6 /N 2 and CO 2 /N 2 selectivity > 31 and 29, respectively. Furthermore, the catalytic activity of CAU‐17 was studied in the regioselective ring‐opening of styrene oxide by methanol to obtain 2‐methoxy‐2‐phenylethanol, thus demonstrating the existence of coordinatively unsaturated sites in the crystal structure of CAU‐17.