Mineralization‐Inspired Synthesis of Magnetic Zeolitic Imidazole Framework Composites

Metal–organic frameworks (MOFs) capable of mobility and manipulation are attractive materials for potential applications in targeted drug delivery, catalysis, and small‐scale machines. One way of rendering MOFs navigable is incorporating magnetically responsive nanostructures, which usually involve at least two preparation steps: the growth of the magnetic nanomaterial and its incorporation during the synthesis of the MOF crystals. Now, by using optimal combinations of salts and ligands, zeolitic imidazolate framework composite structures with ferrimagnetic behavior can be readily obtained via a one‐step synthetic procedure, that is, without the incorporation of extrinsic magnetic components. The ferrimagnetism of the composite originates from binary oxides of iron and transition metals such as cobalt. This approach exhibits similarities to the natural mineralization of iron oxide species, as is observed in ores and in biomineralization.     

Successful Decontamination of 99TcO4− in Groundwater at Legacy Nuclear Sites by a Cationic Metal‐Organic Framework with Hydrophobic Pockets

⁹⁹Tc contamination at legacy nuclear sites is a serious and unsolved environmental issue. The selective remediation of ⁹⁹TcO₄^? in the presence of a large excess of NO₃^? and SO₄^2? from natural waste systems represents a significant scientific and technical challenge, since anions with a higher charge density are often preferentially sorbed by traditional anion‐exchange materials. We present a solution to this challenge based on a stable cationic metal‐organic framework, SCU‐102 (Ni₂(tipm)₃(NO₃)₄), which exhibits fast sorption kinetics, a large capacity (291 mg g^?1), a high distribution coefficient, and, most importantly, a record‐high TcO₄^? uptake selectivity. This material can almost quantitatively remove TcO₄^? in the presence of a large excess of NO₃^? and SO₄^2?. Decontamination experiments confirm that SCU‐102 represents the optimal Tc scavenger with the highest reported clean‐up efficiency, while first‐principle simulations reveal that the origin of the selectivity is the recognition of TcO₄^? by the hydrophobic pockets of the structure.     

An Auto‐Switchable Dual‐Mode Seawater Energy Extraction System Enabled by Metal–Organic Frameworks

Harvesting energy directly in oceans by electrochemical devices is essential for driving underwater appliances such as underwater vehicles or detectors. Owing to the extreme undersea environment, it is important but difficult to use the devices with both a high energy density and power density simultaneously. Inspired by marine organisms that have switchable energy extraction modes (aerobic respiration for long‐term living or anaerobic respiration to provide instantaneously high output power for fast movement), an auto‐switchable dual‐mode seawater energy extraction system is presented to provide high energy density and power density both by initiatively choosing different solutes in seawater as electron acceptors. With assistance from metal–organic frameworks, this device had a theoretical energy density of 3960 Wh kg^?1, and a high practical power density of 100±4 mW cm^?2 with exceptional stability and low cost, making practical applications in seawater to be possible.     

A Tale of Two Trimers from Two Different Worlds: A COF‐Inspired Synthetic Strategy for Pore‐Space Partitioning of MOFs

The introduction of a symmetry‐ and size‐matching pore‐partitioning agent in the form of either a molecular ligand, such as 2,4,6‐tri(4‐pyridinyl)‐1,3,5‐triazine ( tpt ), or a metal‐complex cluster, into the hexagonal channels of MIL‐88/MOF‐235‐type (the acs net) to create pacs ‐type (partitioned acs ) crystalline porous materials is an effective strategy to develop high‐performance gas adsorbents. We have developed an integrated COF–MOF coassembly strategy as a new method for pore‐space partitioning through the coassembly of [(M₃(OH)_1?x(O)_x(COO)₆] MOF‐type and [B₃O₃(py)₃] COF‐type trimers. With this strategy, the coordination‐driven assembly of the acs framework occurred concurrently and synergistically with the COF‐1‐type condensation of pyridine‐4‐boronic acid into a C₃‐symmetric trimeric boroxine molecule. The resulting boroxine‐based pacs materials exhibited dramatically enhanced gas‐sorption properties as compared to nonpartitioned acs ‐type materials and are among the most efficient NH₃‐sorption materials.     

Particle‐in‐a‐Frame Nanostructures with Interior Nanogaps

Designing plasmonic hollow colloids with small interior nanogaps would allow structural properties to be exploited that are normally linked to an ensemble of particles but within a single nanoparticle. Now, a synthetic approach for constructing a new class of frame nanostructures is presented. Fine control over the galvanic replacement reaction of Ag nanoprisms with Au precursors gave unprecedented Au particle‐in‐a‐frame nanostructures with well‐defined sub‐2 nm interior nanogaps. The prepared nanostructures exhibited superior performance in applications, such as plasmonic sensing and surface‐enhanced Raman scattering, over their solid nanostructure and nanoframe counterparts. This highlights the benefit of their interior hot spots, which can highly promote and maximize the electric field confinement within a single nanostructure.     

Metal–Organic Framework (MOF) Nanorods,Nanotubes, and Nanowires

New mechanisms for the controlled growth of one‐dimensional (1D) metal–organic framework (MOF) nano‐ and superstructures under size‐confinement and surface‐directing effects have been discovered. Through applying interfacial synthesis templated by track‐etched polycarbonate (PCTE) membranes, congruent polycrystalline zeolitic imidazolate framework‐8 (ZIF‐8) solid nanorods and hollow nanotubes were found to form within 100 nm membrane pores, while single crystalline ZIF‐8 nanowires grew inside 30 nm pores, all of which possess large aspect ratios up to 60 and show preferential crystal orientation with the {100} planes aligned parallel to the long axis of the pore. Our findings provide a generalizable method for controlling size, morphology, and lattice orientation of MOF nanomaterials.