Engineering new defective phases of UiO family metal–organic frameworks with water

Abstract

As defects significantly affect the properties of metal-organic frameworks (MOFs)-from changing their mechanical properties to enhancing their catalytic ability-obtaining synthetic control over defects is essential to tuning the effects on the properties of the MOF. Previous work has shown that synthesis temperature and the identity and concentration of modulating acid are critical factors in determining the nature and distribution of defects in the UiO family of MOFs. In this paper we demonstrate that the amount of water in the reaction mixture in the synthesis of UiO family MOFs is an equally important factor, as it controls the phase which forms for both and UiO-66(Hf) (F 4 BDC). We use this new understanding of the importance of water to develop a new route to the stable defect-ordered hcp UiO-66(Hf) phase, demonstrating the effectiveness of this method of defect-engineering in the rational design of MOFs. The insights provided by this investigation open up the possibility of harnessing defects to produce new phases and dimensionalities of other MOFs, including nanosheets, for a variety of applications such as MOF-based membranes.Zirconium and hafnium MOFs, including the UiO family, exhibit a wide range of defect chemistry. As defects alter the properties of the framework, obtaining control over the type, location and concentration of defects will in turn allow control over the properties of the MOF. 9,14-17 UiO-66 is an ideal system for study-

Correlated disorder in metal–organic frameworks

“…11,68 An intriguing recent development along similar lines is the concept of using correlated disordered states as intermediates in materials synthesis to target low-dimensional phases. 17 But we note in conclusion the possible additional importance of different types of correlated disorder in MOFs to those outlined here-involving e.g. frustrated magnetism, 78 local charge ordering, 81 or cooperative spin-state transitions.…”

“…It is no accident then that controlling the correlations within disordered MOFswhether involving vacancy, composition, or linker orientation distributions-is an essential aspect of defect engineering. 2,[16][17][18] Distinguishing correlated disorder from random disorder is often a nontrivial experimental and computational challenge. Conventional crystallography, which has played such an important historical role in MOF science, probes only the average structure of materials: it is demonstrably insensitive to correlations within disordered states.…”

Cracking the Chloroquine Conundrum: The Application of Defective UiO-66 Metal–Organic Framework Materials to Prevent the Onset of Heart Defects—In Vivo and In Vitro

“… 32 It may be observed that, for all prepared samples, the characteristic PXRD patterns correspond to the FC topology. 32 − 34 …”

High Throughput Methods in the Synthesis, Characterization, and Optimization of Porous Materials

“…SBUs are treated as genetic structural units and reacted together according to consideration of their functional groups in a manner reminiscent of Wilmer et al, [ 314 ] with the distinction that 2D materials were explicitly targeted in this work as well as 3D materials. 2D MOFs have become a recent area of great interest (see e.g., Cliffe et al [ 391 ] and Firth et al [ 392 ] ) for their potential use in catalysis and/or as membranes for example, hence it would be interesting to see the targeting of 2D MOFs. Although the generated structures were optimized using the DREIDING force field and/or Forcite, the structures were not ranked according to thermodynamic stability, which would be a logical way to assess the synthetic viability, as was done in a landmark study by Lukose et al [ 393 ] in 2010 using tight binding DFT approaches implemented in the deMON2k package.…”