Control of Metal–Organic Framework Crystallization by Metastable Intermediate Pre‐equilibrium Species. Issue 2 (7th December 2018)

• Record Type: Journal Article
• Authors: Yeung, Hamish H.‐M.; Sapnik, Adam F.; Massingberd‐Mundy, Felicity; Gaultois, Michael W.; Wu, Yue; Fraser, Duncan A. X.; Henke, Sebastian; Pallach, Roman; Heidenreich, Niclas; Magdysyuk, Oxana V.; Vo, Nghia T.; Goodwin, Andrew L.
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 2(2019)
• Page Start: 566
• Page End: 571
• Publication Date: 2018-12-07
• Subjects: crystal engineering -- kinetics -- metal–organic frameworks -- nanoparticles -- reactive intermediates; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201810039
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: There is an increasing amount of interest in metal–organic frameworks (MOFs) for a variety of applications, from gas sensing and separations to electronics and catalysis. However, the mechanisms by which they crystallize remain poorly understood. Herein, an important new insight into MOF formation is reported. It is shown that, prior to network assembly, crystallization intermediates in the canonical ZIF‐8 system exist in a dynamic pre‐equilibrium, which depends on the reactant concentrations and the progress of reaction. Concentration can, therefore, be used as a synthetic handle to directly control particle size, with potential implications for industrial scale‐up and gas sorption applications. These findings enable the rationalization of apparent contradictions between previous studies of ZIF‐8 and opens up new opportunities for the control of crystallization in network solids more generally. Abstract : Counterintuitive crystallization kinetics are uncovered in the metal–organic framework ZIF‐8, using in situ XRD and pH measurements. The findings are explained by a pre‐equilibrium model in which metastable, over‐stoichiometric species inhibit crystallization. The model helps to rationalize apparent contradictions between previous studies and opens up new opportunities for crystallization control in network solids.