Defect concentrations and their compensating groups have been systematically tuned within UiO-66 frameworks by using modified microwave-assisted solvothermal methods. Both of these factors have a pronounced effect on CO2 and H2O adsorption at low and high pressure.

Recent studies have demonstrated that metal-organic frameworks can be employed as protective coatings for enzymes. Two efficient strategies have been reported for the synthesis of such composite materials: biomimetic mineralisation and controlled co-precipitation using polyvinylpyrrolidone. We assessed the relative efficacy of each approach by comparing the thermal stability of encapsulated urease. The resulting data shows that over a range of temperatures biomimetic mineralisation offers superior protection than the co-precipitation method.

Post-synthetic metallation is employed strategically to imbue metal-organic frameworks (MOFs) with enhanced performance characteristics. However, obtaining precise structural information for metal-centred reactions that take place within the pores of these materials has remained an elusive goal, because of issues with high symmetry in certain MOFs, lower initial crystallinity for some chemically robust MOFs, and the reduction in crystallinity that can result from carrying out post-synthetic reactions on parent crystals. Here, we report a new three-dimensional MOF possessing pore cavities that are lined with vacant di-pyrazole groups poised for post-synthetic metallation. These metallations occur quantitatively without appreciable loss of crystallinity, thereby enabling examination of the products by single-crystal X-ray diffraction. To illustrate the potential of this platform to garner fundamental insight into metal-catalysed reactions in porous solids we use single-crystal X-ray diffraction studies to structurally elucidate the reaction products of consecutive oxidative addition and methyl migration steps that occur within the pores of the Rh-metallated MOF, 1·[Rh(CO)2][Rh(CO)2Cl2].

Development of next-generation sensor devices is gaining tremendous attention in both academia and industry because of their broad applications in manufacturing processes, food and environment control, medicine, disease diagnostics, security and defense, aerospace, and so forth. Current challenges include the development of low-cost, ultrahigh, and user-friendly sensors, which have high selectivity, fast response and recovery times, and small dimensions. The critical demands of these new sensors are typically associated with advanced nanoscale sensing materials. Among them, graphene and its derivatives have demonstrated the ideal properties to overcome these challenges and have merged as one of the most popular sensing platforms for diverse applications. A broad range of graphene assemblies with different architectures, morphologies, and scales (from nano-, micro-, to macrosize) have been explored in recent years for designing new high-performing sensing devices. Herein, this study presents and discusses recent advances in synthesis strategies of assembled graphene-based superstructures of 1D, 2D, and 3D macroscopic shapes in the forms of fibers, thin films, and foams/aerogels. The fabricated state-of-the-art applications of these materials in gas and vapor, biomedical, piezoresistive strain and pressure, heavy metal ion, and temperature sensors are also systematically reviewed and discussed, and their sensing performance is compared.

The efficient removal of pertechnetate (TcO4(-)) anions from liquid waste or melter off-gas solution for an alternative treatment is one of the promising options to manage (99)Tc in legacy nuclear waste. Safe immobilization of (99)Tc is of major importance because of its long half-life (t1/2 = 2.13 × 10(5) yrs) and environmental mobility. Different types of inorganic and solid-state ion-exchange materials have been shown to absorb TcO4(-) anions from water. However, both high capacity and selectivity have yet to be achieved in a single material. Herein, we show that a protonated version of an ultrastable zirconium-based metal-organic framework can adsorb perrhenate (ReO4(-)) anions, a nonradioactive surrogate for TcO4(-), from water even in the presence of other common anions. Synchrotron-based powder X-ray diffraction and molecular simulations were used to identify the position of the adsorbed ReO4(-) (surrogate for TcO4(-)) molecule within the framework.

Single-crystal X-ray crystallography is employed to characterize the reaction species of af ull catalytic carbonylation cycle within aM n II -based metal-organic framework (MOF) material. The structural insights explain why the Rh metalated MOF is catalytically competent towardt he carbonylation of MeBr but only affords stoichiometric turn-over in the case of MeI. This work highlights the capability of MOFs to act as platform materials for studying single-site catalysis in heterogeneous systems.

Site-selective organic transformations are commonly required in the synthesis of complex molecules. By employing a bespoke metal-organic framework (MOF, 1·[Mn(CO)N]), in which coordinated azide anions are precisely positioned within 1D channels, we present a strategy for the site-selective transformation of dialkynes into alkyne-functionalized triazoles. As an illustration of this approach, 1,7-octadiyne-3,6-dione stoichiometrically furnishes the mono-"click" product N-methyl-4-hex-5'-ynl-1',4'-dione-1,2,3-triazole with only trace bis-triazole side-product. Stepwise insights into conversions of the MOF reaction vessel were obtained by X-ray crystallography, demonstrating that the reactive sites are "isolated" from one another. Single-crystal to single-crystal transformations of the Mn(I)-metalated material 1·[Mn(CO)(HO)]Br to the corresponding azide species 1·[Mn(CO)N] with sodium azide, followed by a series of [3+2] azide-alkyne cycloaddition reactions, are reported. The final liberation of the "click" products from the porous material is achieved by N-alkylation with MeBr, which regenerates starting MOF 1·[Mn(CO)(HO)]Br and releases the organic products, as characterized by NMR spectroscopy and mass spectrometry. Once the dialkyne length exceeds the azide separation, site selectivity is lost, confirming the critical importance of isolated azide moieties for this strategy. We postulate that carefully designed MOFs can act as physical protecting groups to facilitate other site-selective and chemoselective transformations.

Porous metal–organic polyhedra (MOPs), constructed from heterometallic PdII–MII (M = Cu, Ni, Zn) paddlewheel nodes and 5-tert-butyl-1,3-benzenedicarboxylate organic links, were prepared in which the PdII ions preferentially line the inner surface of the cage molecules.