Chemical and Structural Stability of Zirconium‐based Metal–Organic Frameworks with Large Three‐Dimensional Pores by Linker Engineering

Abstract

The synthesis of metal–organic frameworks with large three-dimensional channels that are permanently porous and chemically stable offers new opportunities in areas such as catalysis and separation. Two linkers (L1=4,4′,4′′,4′′′-([1,1′-biphenyl]-3,3′,5,5′-tetrayltetrakis(ethyne-2,1-diyl)) tetrabenzoic acid, L2=4,4′,4′′,4′′′-(pyrene-1,3,6,8-tetrayltetrakis(ethyne-2,1-diyl))tetrabenzoic acid) were used that have equivalent connectivity and dimensions but quite distinct torsional flexibility. With these, a solid solution material, [Zr6O4(OH)4(L1)2.6(L2)0.4]⋅(solvent)x, was formed that has three-dimensional crystalline permanent porosity with a surface area of over 4000 m2 g−1 that persists after immersion in water. These properties are not accessible for the isostructural phases made from the separate single linkers.

Stable Metal–Organic Frameworks: Design, Synthesis, and Applications

“…However, the stability of many so‐called “stable MOFs” has yet to reach the same level of other inorganic or organic porous materials such as zeolites, mesoporous silica, and porous carbons. On the other hand, the mechanical stability of MOFs, an important consideration for the industrialization process, has not been widely studied so far . Once the stability of MOFs has been addressed, stride can be taken in the industrialization of these unique materials.…”

Solvent‐Assisted Metal Metathesis: A Highly Efficient and Versatile Route towards Synthetically Demanding Chromium Metal–Organic Frameworks

“…[3] In contrast to traditional porous materials such as zeolites and activated carbons,t he porosity and functional sites of MOFs can be precisely tuned by judicious choice of the metal nodes and modification of the organic ligands.H owever,t he labile metal-ligand coordination bonds in early MOFs,mostly with divalent metal ions (e.g., Zn II and Cu II ), have rendered them unstable under many conditions,s uch as upon exposure to moisture and air, which has become an obvious obstacle for the practical application of MOFs in industry. [1c] More recently,M OFs constructed from high-valence metals (hard Lewis acids) and carboxylates (hard Lewis bases), such as those with Cr III , [4a-c, 5, 10c-e] Fe III , [4d-i, 7] and Zr IV [6,8] clusters,h ave received increasing attention because of their improved stability and larger surface areas,w hich would warrant their application as catalysts and adsorbents. However,t he kinetic inertness of such metal-ligand bonds and fast reaction rates result in poor control over the crystallization process,w hich has impeded the facile direct synthesis of these high-valence MOFs.A mong the various MOF families,the number of known Fe III - [7] and Zr IV -MOFs [8] has increased rapidly thanks to the development of modulated synthetic strategies.I nc omparison, Cr III -MOFs with trigonal-prismatic Cr 3 Os econdary building units (SBUs) show superior chemical stability.F or example,m any of them are stable not only in water with aw ider range of pH values but also in alkylamine solutions.…”

“…[1c] More recently,M OFs constructed from high-valence metals (hard Lewis acids) and carboxylates (hard Lewis bases), such as those with Cr III , [4a-c, 5, 10c-e] Fe III , [4d-i, 7] and Zr IV [6,8] clusters,h ave received increasing attention because of their improved stability and larger surface areas,w hich would warrant their application as catalysts and adsorbents. However,t he kinetic inertness of such metal-ligand bonds and fast reaction rates result in poor control over the crystallization process,w hich has impeded the facile direct synthesis of these high-valence MOFs.A mong the various MOF families,the number of known Fe III - [7] and Zr IV -MOFs [8] has increased rapidly thanks to the development of modulated synthetic strategies.I nc omparison, Cr III -MOFs with trigonal-prismatic Cr 3 Os econdary building units (SBUs) show superior chemical stability.F or example,m any of them are stable not only in water with aw ider range of pH values but also in alkylamine solutions. [5, 10d] In addition, the linkages between the Cr 3 OS BUs and polytopic carboxylates would lead to Cr-MOFs with high porosity,a s exemplified by MIL-101(Cr) [4c] and MIL-100(Cr).…”

Preise 2015 der Real Sociedad Española de Química

“…Derzeit befasst er sich vor allem mit Metall‐organischen Gerüstverbindungen und schichtförmigen anorganischen Feststoffen. Er hat als Coautor an einer kürzlich in der Angewandten Chemie erschienenen Arbeit über zirconiumbasierte Metall‐organische Gerüstverbindungen mitgewirkt 9…”