Assembly of Metal–Organic Frameworks (MOFs) Based on Indium‐Trimer Building Blocks: A Porous MOF with soc Topology and High Hydrogen Storage

Abstract

The potential of the molecular-building-block (MBB) approach for the assembly and development of functional solid-state porous materials has already been recognized. [1] This approach offers a prospective avenue toward the design and construction of novel materials; that is, desired properties can be incorporated at the design stage. These properties are required to address the myriad technological challenges that face us, including hydrogen storage for fuel applications. In metal-ligand directed assembly, the MBB approach has been adopted for the synthesis of functional metal-organic assemblies (MOAs), which range from discrete (metal-organic polyhedra) to 3D (metal-organic frameworks (MOFs)). Accordingly, various applications, including nonlinear optics (NLO), magnetism, catalysis, and gas storage, were revealed for MOFs. [2,3] These MOFs have proven exceptional owing to their facile tunability (alteration in pore size and functionality), a feature dependent on the rigidity, modularity, and control of the MBBs. Therefore, prior to the assembly process, it is essential that the MBBs possess certain attributes for the construction of targeted structures: each must be rigid, impart the desired directionality, and possess the necessary shape and geometry for that structure.Organic chemistry would seem to offer a vast repertoire to be employed as MBBs, because organic molecules can be designed to contain these features. Nevertheless, organicmolecule-based MBBs with high connectivity are not common, and their assembly into crystalline porous organic frameworks remains a challenge.[4] As such, alternative routes have been pursued combining organic MBBs and inorganic MBBs derived from metal-ligand coordination. Unlike organic MBBs, which are selected already possessing the desired features, typically inorganic MBBs are formed in situ. As a result, reaction conditions to generate a specific inorganic MBB consistently in situ are vital; once established, desired MOAs can be designed and (potentially) assembled by judicious choice of organic ligands. It is clear that continuous development and isolation of novel MBBs will eventually facilitate the rational construction of targeted functional MOAs, an example of design versus serendipity.Strategies based on the MBB approach have already shown promise toward the design and construction of MOAs, and, accordingly, some basic guidelines have been derived: [1] 1) It is essential that the desired inorganic building blocks can be targeted. 2) The organic linker must have specific functionalities that give rise to the desired shape, geometry, and rigidity upon coordination. 3) Reaction conditions must introduce the ability to generate crystalline materials, a result that is vital for structural analysis and correlations between structure and building units. 4) It is accepted that the assembly of simple building blocks, in the absence of any altering agent such as a template or structure directing agent (SDA), will lead to the construction of the default structure relative to...

Structural and elemental influence from various MOFs on the performance of Fe@C catalysts for Fischer–Tropsch synthesis

“…N 2 physisorption at 77 K, TGA and XRD confirmed the presence of MIL-68 [21][22][23] , MIL-88A [24][25][26] , MIL-100 [27][28][29] , MIL-101 [30][31][32] , and MIL-127 [33][34][35] (see Table S1, Figure S1 and Figure S2) ‡. XRD of the F300 Fe-BTC MOF revealed a very low degree of crystallinity, but the MIL-100 topology was confirmed since the isotherm contained an additional step in the micropore regime corresponding to the large cages in the MTN-type framework [27][28] .…”

Structures and H2 Adsorption Properties of Porous Scandium Metal–Organic Frameworks

“…In order to enhance the H 2 binding energy in these materials, strategies such as the formation of very narrow pores [14,15,17] (in which overlapping potentials from two or more pore walls increases the binding energy between the H 2 and the framework), framework catenation/interpenetration [18] and doping of frameworks with light electron-donating non-transition-metal centres to increase H 2 uptake [19] have been undertaken. In particular, access to exposed metal sites can increase the affinity of H 2 through direct coordination to metal centres.…”

Porous, rigid metal(III)-carboxylate metal-organic frameworks for the delivery of nitric oxide

“…11 To address this issue, we focused our attention to other iron(III)-carboxylate based MOFs (Figure 1) that not only possess the same building units as the MIL-88 series, and thus large amounts of Lewis acid sites, but also rigid frameworks with larger windows/pores, namely, MIL-100 (Cr, Fe) 13 and MIL-127(Fe) 14 (analogous to soc-MOF(In) 15 ). MIL-100 possesses two types of mesoporous cages (d ∼ 24 and 29 Å, respectively), accessible through microporous pentagonal and hexagonal windows, while MIL-127(Fe) exhibits a 3D microporous system (d ∼ 5-7 Å) with both hydrophobic and hydrophilic features 15 ( Figure 1). It has previously been shown that these particular MOFs easily adsorb or separate various types of gas molecules and their ability to coordinate polar or quadrupolar molecules (water, alcohols, C3, etc.)…”