Coligand-Rigidity Induced Interpenetration in Flexible Bis-imidazolyl Type Linker Based Mixed Ligand Metal–Organic Frameworks

Abstract

Interpenetration or catenation is well explored in the network structure of metal organic frameworks, but these kinds of networks were considered as not usable for normal applications of conventional open metal−organic frameworks (MOFs). Recently, flexibility in such networks was found to be an important factor to introduce functionality in the structures of MOFs, and also, the understanding of the factors that control interpenetration also become important. To date, there is no obvious root that has been found to have an interpenetrated network with successive flexibility. In search of such types of networks and to explore the avenue of understanding of growing interpenetration in a framework, six new metal−organic frameworks (MOFs) of Cu(II), Cd(II), and Zn(II) have been synthesized from three flexible dicarboxylates and two rigid dicarboxylates along with 2-methyl-1-(4-(2-methyl-1H-imidazole-1-yl)butyl)-1H-imidazole, as a coligand. All of these synthesized complexes have been characterized by single crystal and powder X-ray diffraction and were further characterized by elemental analysis, infrared spectroscopy (IR), and thermogravimetric analysis (TGA). N 2 , CO 2 , H 2 , and CH 4 sorption studies were also done for all the MOFs, and the characteristic surface adsorptions were found in all cases. Here, from the studies of all these complexes, a common observation is found: flexible dicarboxylates give a noninterpenetrated framework whereas rigid linkers give an interpenetrated framework.

Solvent-Induced Two Co-Based 3D Metal–Organic Frameworks as Platforms for the High Degradation of Rhodamine B Under Sunlight

“…As is known, the photocatalytic effect of MOFs strongly depends on the central metals and the conjugation degree of organic ligands. Organic ligands also influence the self-assembly of porous MOFs, endowing MOFs the diversity in shape and size of pores. − The abundant catalytic sites and specific surface areas make MOFs possess outstanding catalytic activities. − Some MOFs containing 4,4′,4″-nitrilotribenzoic acid (H 3 NTB) ligands were usually reported to have photocatalytic activity. For example, Lan’s group synthesized a series of MOFs utilizing H 3 NTB ligands, which showed highly photocatalytic activities for the CO 2 reduction reaction. , Su’s group obtained a 3D Co-MOF with a twofold interpenetrating structure by using H 3 NTB ligands, which acted as a heterogeneous catalyst to degrade RhB in water through activating peroxymonosulfate (PMS) to generate sulfate radicals .…”

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. , …”

A Cobalt-Organic Framework with Sensitive Detection of Fe3+, Cr2O72–, and CrO42– Ions in Water

“…In general, the uorescent MOFs are constructed with aromatic ligands because the π electron systems of the ligands endow the MOFs with photoluminescence properties and provide potential supramolecular recognition sites between the backbones and analytes [17]. The mixed-ligands approach is implemented by the judicious choice of carboxylates with aromatic π rings and N-donor linkers can afford novel uorescent MOFs [18,19]. Among the transition metal ions, Co 2+ is widely used in the synthesis of MOFs because of its excellent coordination ability and potential function as an electrochemically active center; moreover, it is widely abundant and inexpensive.…”