Increasing the Complexity in the MIL‐53 Structure: The Combination of the Mixed‐Metal and the Mixed‐Linker Concepts

Abstract

The isoreticular mixed‐component concept is a promising approach to tailor the material properties of metal–organic frameworks. While isoreticular mixed‐metal or mixed‐linker materials are commonly synthesized, the combination of both concepts for the development of isoreticular materials featuring both two metals and two linkers is still rarely investigated. Herein, we present the development of mixed‐metal/mixed‐linker MIL‐53 materials that contain different metal combinations (Al/Sc, Al/V, Al/Cr, Al/Fe) and different linker ratios (terephthalate/2‐aminoterephthalate). The possibility of changing the metal combination and the linker ratio independently from each other enables a large variety of modifications. A thorough characterization (PXRD, ATR‐IR, TGA, 1H NMR, ICP‐OES) confirmed that all components were incorporated into the framework structure with a statistical distribution. Nitrogen physisorption measurements showed that the breathing behavior can be tailored by adjusting the linker ratio for all metal combinations. All materials were successfully used for post‐synthetic modification reactions with maleic anhydride.

Breathing Behaviour Modification of Gallium MIL‐53 Metal–Organic Frameworks Induced by the Bridging Framework Inorganic Anion

“…[4] The thermoresponsive breathing behaviour of [MX(bdc)] MIL-53 MOFs can be directed through changing the trivalent metal, M, [4][5][6][7][8][9][10][11] incorporating mixtures of two different metals, M and M', [12,13,14] partially substituting the bdc 2À linkers for other dicarboxylate-based linkers, [15,16] or a mixture of these strategies. [17] Another potential route to direct the flexibility of these materials is to change the nature of the μ 2 -bridging X À anions. A markedly different thermoresponsive behaviour for [Al(X)(bdc)] has been reported.…”

Does Mixed Linker-Induced Surface Heterogeneity Impact the Accuracy of IAST Predictions in UiO-66-NH2?

“…Metal–organic frameworks (MOFs) are ideal for systematic studies of adsorption in nanoporous materials due to their high tunability and modular assembly . In particular, mixed-linker MOFs, where differently functionalized linkers are combined in one structure, result in a controllable extent of surface heterogeneity imparted on the internal pore surfaces and exhibit tunable adsorption behavior. − This mixed-linker approach has been reported for a variety of MOFs such as IRMOF-1, MIL-53, MIL-101­(Cr), different ZIFs, ,, and UiO-66. − These multilinker materials provide a suitable platform to investigate and understand fundamental contributions to nonideal adsorption behavior and probe the limits of IAST.…”

Surface-Modified Ultrathin Metal–Organic Framework Nanosheets as a Single-Site Iron Electrocatalyst for Oxygen Evolution Reaction

“…MOFs are usually classified as uniform heterogeneous catalysts, a subclass of single-site heterogeneous catalysts, as the homogeneously distributed unsaturated vacancies of the inorganic node can play the role of catalytic active sites. Alternately, the organic linkers of MOFs can be pre-synthetically or post-synthetically modified with different functional groups, − and the active sites can be controllably introduced into the resulting mixed-linker MOFs, , which combine the advantages of both homogeneous and heterogeneous catalysts, also facilitate the development of quasimolecular heterogeneous catalysts. − The catenation or interpenetration of frameworks, cavity and aperture expansion in the modification process, as well as painful and multistep organic synthesis remain as the main challenges for the preparation of mixed-linker MOF catalysts. , …”