Zn(II)/Cd(II)-Based Metal–Organic Frameworks as Bifunctional Materials for Dye Scavenging and Catalysis of Fructose/Glucose to 5-Hydroxymethylfurfural

Abstract

Functional neutral metal–organic frameworks (MOFs) {[M­(5OH-IP)­(L)]} n [M = Zn­(II) for ADES-4; Cd­(II) for ADES-5; 5OH-IP = 5-hydroxyisophthalate; L = (E)-N′-(pyridin-3-ylmethylene)­nicotinohydrazide) have been synthesized by a diffusion/conventional reflux/mechanochemical method and characterized by various analytical techniques. Crystals were harvested by a diffusion method, and single-crystal X-ray diffraction (SXRD) analysis revealed that an adjacent [M2(COO)2] n ladder chain generates isostructural two-dimensional network motifs by doubly pillaring via L. The bulk-phase purity of ADES-4 and ADES-5 synthesized by a versatile synthetic approach has been recognized by the decent match of powder X-ray diffraction patterns with the simulated one. Both ADES-4 and ADES-5 showed selective adsorption of cationic dyes methylene blue (MB), methyl violet (MV), and rhodamine B (RhB) over anionic dye methyl orange (MO) from water with good uptake and rapid adsorption. Utilization of ADES-4 as a chromatographic column filler for adsorptive removal of individual cationic dyes as well as a mixture of dyes has been demonstrated from the aqueous phase. Interestingly, ADES-4 is reusable with good stability, and it showed a dye desorption phenomenon in methanol. The probable mechanism of cationic dye removal based on insight from structural information and plausible supramolecular interactions has also been explored. Both MOFs also showed efficient catalytic transformation of fructose and glucose into the high-value chemical intermediate 5-hydroxymethylfurfural of industrial significance.

Bifunctional {Pb10K2}–Organic Framework for High Catalytic Activity in Cycloaddition of CO2 with Epoxides and Knoevenagel Condensation

“…In addition, the excessive emission of carbon dioxide (CO 2 ) has led to a series of serious ecological problems such as global warming and ocean level rising, which make the technology of CO 2 capture and utilization (CCU) widely concerned. − At present, the technical means of using CO 2 to synthesize valuable chemicals can not only effectively reduce the CO 2 content in the environment but also bring huge economic benefits to mankind, which has gradually become one of the most favorable strategies. , So far, it is found that the synthetic technology of cyclic carbonates from CO 2 and epoxides is one of the most effective ways, which can realize the dual functions of solving environmental problems and resource utilization, as cyclic carbonates are a kind of widely used chemicals and chemical raw materials. − However, at present, the catalysts used for producing cyclic carbonates in the industry are mainly organic and inorganic halogenated salts, which have many disadvantages, such as strong pollution, low catalytic efficiency, and difficult separation. − However, the synergistic effect of the exposed metal cations (Lewis acids) and the basic groups (Lewis bases) in microporous MOFs leads to the excellent catalytic activity in the cycloaddition reaction of CO 2 with epoxides. − Furthermore, to enhance the selectivity and catalytic activity, the confined pore environments of MOFs can be adjusted using carefully designed structure-oriented ligands and adjusting the growth environments. , Among all reported MOFs, PbOFs account for a small proportion and are usually based on the most common SBUs, such as monomeric [Pb­(CO 2 ) n ]. , However, the excellent catalytic ability derived from the high-level p-orbitals of the Pb 2+ ion gives scientists impetus to explore more perfect lead–organic frameworks.…”

Construction of a 3D Metal–Organic Framework and Its Composite for Water Remediation via Selective Adsorption and Photocatalytic Degradation of Hazardous Dye

“…Conversely, as we increase the pH range from neutral to alkaline, pH = 11, it can be seen that the adsorption capacity (∼42%) decreases significantly due to the negative part of MB interacting with the base forming NaCl. 63 , 69c , 70 , 71a The effect of pH on the uptake capacity has been shown with 1 being a better adsorbent at a pH of 7 with 85.2% removal efficiency of MB dye.…”

Multiple Construction of a Hierarchical Nanoporous Manganese(II)-Based Metal–Organic Framework with Active Sites for Regulating N2 and CO2 Trapping

“…The type of metal , (coordination capability and number, the metal–linker bond strength, inertness or lability, oxidation states), ligand − (type of donor group, rigidity or flexibility of the structure, angle of rotation of donor groups, and coordination modes), solvent (size, substituent and coordination mode, boiling point), reaction temperature, , pH value, and synthesis method are key factors to the physical and chemical properties of the final structures of MOFs. They have different applications for gas storage, − catalysis, − nanocarriers for drug delivery, − sensing, − antibacterial activity, , separation selectivity of gas mixtures, , and ion conductivity and transport. , The precise design and synthesis of new MOFs with the desired crystal structures are major challenges for scientists . There are many ligands for the construction of MOFs, although most of them frequently create limited structures.…”