Iron-Based Metal–Organic Frameworks MIL-88B and NH₂-MIL-88B: High Quality Microwave Synthesis and Solvent-Induced Lattice “Breathing”

Abstract

Iron-based MIL-88B and NH 2 -MIL-88B microcrystals with high dispersibility and uniform size were successfully synthesized by using a rapid microwave-assisted solvothermal method. By carefully controlling the reaction conditions, the microwave method provided superior quality MIL-88B crystals in high yields and excellent phase purity. Framework flexibility was observed for both MIL-88B-Fe and NH 2 -MIL-88B-Fe frameworks in various solvents, which however significantly differs between the two materials. MIL-88B-Fe shrinks reversibly by about 25% only when it is dispersed in the strongly hydrogen bonding solvents water or methanol. In contrast, NH 2 -MIL-88B-Fe shrinks up to 33% upon replacement of dimethylformamide (DMF) by any other solvent studied (benzene, chloroform, acetone, acetonitrile, methanol, water). The change in unit cell parameters (shortening of the a axis) can be seen macroscopically, although the overall integrity of the materials is maintained. We suggest that hydrogen bonding between the oxygen atoms of the MIL-88B-Fe framework and solvent molecules plays an important role in the framework shrinkage, while in the NH 2 -MIL-88B-Fe framework additional hydrogen bonds may form and thus a different breathing behavior is observed.

In Situ Grown Bimetallic MOF‐Based Composite as Highly Efficient Bifunctional Electrocatalyst for Overall Water Splitting with Ultrastability at High Current Densities

“…The reaction mixture was heated at 125 °C for 5 h to yield the NFN-MOF/NF composite (Scheme 1). The crystalline structure of the bulk and sheet NFN-MOFs were characterized with powder X-ray diffraction (XRD) and confirmed with the simulated diffraction pattern of NH 2 -MIL-88B(Fe 3 ) [40] (Figure 1a). For comparison purposes, the NFN-MOF was also prepared without addition of the NF, and the products were termed the bulk NFN-MOF.…”

Smart Nanocomposites of Cu-Hemin Metal-Organic Frameworks for Electrochemical Glucose Biosensing

“…1C). Due to different linkages between metal ions and organic ligands, MOFs could present various morphologies including rod octahedron4244, nanosphere45, hexahedron4546, spindle-shape47, and so on. However, such ball-flower-like structure has not yet been reported in previous works.…”

Fabrication of a magnetic nanoparticle embedded NH2-MIL-88B MOF hybrid for highly efficient covalent immobilization of lipase

“…43 The prominent diffraction peaks are located at 2θ = 9°, 16 However it should be noted that the intensity of different peaks related to NH 2 -MIL-88B as well as Fe 3 O 4 was decreased. 43 The prominent diffraction peaks are located at 2θ = 9°, 16 However it should be noted that the intensity of different peaks related to NH 2 -MIL-88B as well as Fe 3 O 4 was decreased.…”