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Concerns regarding water contamination are escalating due to the increasing presence of all types of pollutants in water sources, which pose serious health risks to humans and wildlife, disrupt ecosystems, and compromise the safety of drinking water. Addressing water contamination requires stringent regulations and increased public awareness, but especially, it requires the development of highly effective new technologies to decontaminate those aquatic environments that have been already polluted over the past few decades. Since the emergence of metal–organic frameworks (MOFs), their use has been proposed in a multitude of fields, given their unique physicochemical properties, and one of the fields where a realistic application can be expected in the near future is water remediation. In particular, oxamidato-based biological MOFs (bioMOFs) have demonstrated, in recent years, unique properties such as extraordinary robustness, crystallinity and water- and pH-stability as well as very easy functionalisation, which situates them among the best adsorbents for this environmental purpose. In this review, we have summarised the most remarkable results of oxamidato-based bioMOFs in the field of water remediation. Moreover, on the basis of the reported results, we dare to suggest the real possibilities of application, in relevant real-world environments, for these and other MOFs, as well as the main obstacles that will need to be overcome, aiming to widening the range of applicability of MOFs and making solid headway towards sustainable development. [ABSTRACT FROM AUTHOR]

The intrinsic characteristic features of metal–organic frameworks offer unique, great opportunities to develop novel materials with applications in very diverse fields. Aiming to take advantage of these, the application of post-synthetic methodologies has revealed itself to be a powerful approach to the isolation and structuration of metal ions, molecules, or more complex species, either within MOF channels or reticulated at their network, rendering novel and exciting MOFs with new or improved functionalities. Herein, we report the partial post-synthetic metal exchange of Zn(II) metal ions by Co(II) ones in water-stable three-dimensional CaZn6-MOF 1, derived from the amino acid S-methyl-L-cysteine, allowing us to obtain two novel MOFs with increasing contents of the Co(II) ions Co4%@1 and Co8%@1. Remarkably, the presented post-synthetic metal exchange methodology has two relevant implications for us: (i) it allowed us to obtain two novel MOFs, which were not accessible by direct synthesis, and (ii) enabled us to transform physical properties within this family of isoreticular MOFs from the diamagnetic pristine MOF 1 to MOFs Co4%@1 and Co8%@1, exhibiting field-induced, frequency-dependent, alternating current magnetic susceptibility signals, which are characteristic features of single-molecule magnets. [ABSTRACT FROM AUTHOR]

Host–guest chemistry within the confined space of metal–organic frameworks (MOFs) offers an almost unlimited myriad of possibilities, hardly accessible with other materials. Here we report the synthesis and physical characterization, with atomic resolution by single-crystal X-ray diffraction, of a novel water-stable tridimensional MOF, derived from the amino acid S-methyl- L -cysteine, {SrZn6[(S,S)-Mecysmox]3(OH)2(H2O)}·9H2O (1), and its application as a robust and efficient solid catalyst for the cycloaddition reaction of ethylene/propylene oxide with CO2 to afford ethylene/propylene carbonate with yields of up to 95% and selectivity of up to 100%. These results nicely illustrate the great potential of MOFs to be game changers for the selective synthesis of industrially relevant products, representing a powerful alternative to the current heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

β‐Lactam antibiotics are one of the most commonly prescribed drugs to treat bacterial infections. However, their use has been somehow limited given the emergence of bacteria with resistance mechanisms, such as β‐lactamases, which inactivate them by degrading their four‐membered β‐lactam rings. So, a total knowledge of the mechanisms governing the catalytic activity of β‐lactamases is required. Here, we report a novel Zn‐based metal–organic framework (MOF, 1), possessing functional channels capable to accommodate and interact with antibiotics, which catalyze the selective hydrolysis of the penicillinic antibiotics amoxicillin and ceftriaxone. In particular, MOF 1 degrades, very efficiently, the four‐membered β‐lactam ring of amoxicillin, acting as a β‐lactamase mimic, and expands the very limited number of MOFs capable to mimic catalytic enzymatic processes. Combined single‐crystal X‐ray diffraction (SCXRD) studies and density functional (DFT) calculations offer unique snapshots on the host‐guest interactions established between amoxicillin and the functional channels of 1. This allows to propose a degradation mechanism based on the activation of a water molecule, promoted by a Zn‐bridging hydroxyl group, concertedly to the nucleophilic attack to the carbonyl moiety and the cleaving of C−N bond of the lactam ring. [ABSTRACT FROM AUTHOR]

Ultrasmall silver clusters in reduced state are difficult to synthesize since silver atoms tend to rapidly aggregate into bigger entities. Here, we show that dimers of reduced silver (Ag2) are formed within the framework of a metal–organic framework provided with thioether arms in their walls (methioMOF), after reduction with NaBH4 of the corresponding Ag+-methioMOF precursor. The resulting Ag2-methioMOF catalyzes the methanation reaction of carbon dioxide (CO2 to CH4 hydrogenation reaction) under mild reaction conditions (1 atm CO2, 4 atm H2, 140 °C), with production rates much higher than Ag on alumina and even comparable to the state-of-the-art Ru on alumina catalyst (Ru–Al2O3) under these reaction conditions, according to literature results. [ABSTRACT FROM AUTHOR]

Since the emergence of metal–organic frameworks (MOFs), a myriad of thrilling properties and applications, in a wide range of fields, have been reported for these materials, which mainly arise from their porous nature and rich host–guest chemistry. However, other important features of MOFs that offer great potential rewards have been only barely explored. For instance, despite the fact that MOFs are suitable candidates to be used as chemical nanoreactors for the preparation, stabilization and characterization of unique functional species, that would be hardly accessible outside the functional constrained space offered by MOF channels, only very few examples have been reported so far. In particular, we outline in this feature recent advances in the use of highly robust and crystalline oxamato- and oxamidato-based MOFs as reactors for the in situ preparation of well-defined catalytically active single atom catalysts (SACS), subnanometer metal nanoclusters (SNMCs) and supramolecular coordination complexes (SCCs). The robustness of selected MOFs permits the post-synthetic (PS) in situ preparation of the desired catalytically active metal species, which can be characterised by single-crystal X-ray diffraction (SC-XRD) taking advantage of its high crystallinity. The strategy highlighted here permits the always challenging large-scale preparation of stable and well-defined SACs, SNMCs and SCCs, exhibiting outstanding catalytic activities. [ABSTRACT FROM AUTHOR]

This perspective review shows how the coordination chemistry approach to magnetic wires based on dinuclear copper(II) complexes with rodlike aromatic oligomers (RAOs) as extended π-conjugated spacers can be extended to the design and synthesis of a novel class of metallo-carbon nanostructures (MCNs) with polycyclic aromatic hydrocarbons (PAHs) as illustrative examples of advanced magnetic nanodevices for single-molecule spintronics and quantum computing nanotechnologies. In this pursuit, two opposite but complementary ways have been explored: (i) the preparation of synthetic models through the skillful organic synthesis of tailor-made diamine-functionalized RAOs and PAHs as bridging ligands for experimental investigation of their single-molecule electron exchange (EE) and electron transport (ET) or quantum interference (QI) and quantum coherence (QC) properties, or (ii) their theoretical prediction with the aid of first-principle density functional (DFT) and time-dependent density functional (TDDFT) theories on appropriate models from chemists' creative imagination. [ABSTRACT FROM AUTHOR]

Based on a β-diketiminate ligand, an iron(III) tetrahedral high-spin complex, [LFeIII(Cl)2] (1), and an iron(II) high-spin triangular planar complex, [LFeIICl] (2), have been synthesized and structurally characterized. Also, complex 1 can be considered as a precursor to produce 2via a reduction process, with a concomitant change in its magnetic anisotropy. Combined experiments and ab initio calculations support the observation of field-induced single-ion magnet (SIM) behaviour for 2 with an effective spin-reversal energy barrier of Ueff = 40.02 K, as a direct consequence of the large intrinsic magnetic anisotropy (easy axis) arising from out-of-state spin-orbit coupling in the trigonal planar FeII complex. Noteworthy butterfly hysteresis loops were observed from 2 up to 8 K, which represents the first case in Fe(II) complexes. [ABSTRACT FROM AUTHOR]

Allylic alcohol epoxidation and dehydrogenation reactivity is distinguished when VO(acac)2 is used in solution or anchored in a metal–organic framework (MOF). The chemical mechanism depends on the electronic profile of alkene substituents when the vanadyl complex is used in the homogenous phase. However, confinement effects imparted by MOF channels allow gaining control of the chemoselectivity toward the dehydrogenation product. [ABSTRACT FROM AUTHOR]

The search for efficient technologies empowering the selective capture of environmentally harmful heavy metals from wastewater treatment plants, at affordable prices, attracts wide interest but constitutes an important technological challenge. We report here an eco-friendly single-walled carbon nanotube buckypaper (SWCNT-BP) enriched with a multivariate amino acid-based metal–organic framework (MTV-MOF) for the efficient and selective removal of Pb2+ in multicomponent water systems. Pristine MTV-MOF was easily immobilized within the porous network of entangled SWCNTs, thus obtaining a stable self-standing adsorbing membrane filter (MTV-MOF/SWCNT-BP). SWCNT-BP alone shows a moderately good removal performance with a maximum adsorption capacity of 180 mg·g–1 and a considerable selectivity for Pb-(II) ions in highly concentrated multi-ion solutions over a wide range of lead concentration (from 200 to 10000 ppb). Remarkably, these features were outperformed with the hybrid membrane filter MTV-MOF/SWCNT-BP, exhibiting enhanced selectivity and adsorption capacity (310 mg·g–1, which is up to 42% higher than that of the neat SWCNT-BP) and consequently enabling a more efficient and selective removal of Pb2+ from aqueous media. MTV-MOF/SWCNT-BP was able to reduce [Pb2+] from the dangerous 1000 ppb level to acceptable limits for drinking water, below 10 ppb, as established by the current EPA and WHO limits. Thus, the eco-friendly composite MTV-MOF/SWCNT-BP shows the potential to be effectively used several times as a reliable adsorbent for Pb2+ removal for household drinking water or in industrial treatment plants for water and wastewater lead decontamination. [ABSTRACT FROM AUTHOR]

Extremely high electrophilic metal complexes, composed by a metal cation and very electron poor σ‐donor ancillary ligands, are expected to be privileged catalysts for oxidation reactions in organic chemistry. However, their low lifetime prevents any use in catalysis. Here we show the synthesis of fluorinated pyridine‐Pd2+ coordinate cages within the channels of an anionic tridimensional metal‐organic framework (MOF), and their use as efficient metal catalysts for the aerobic oxidation of aliphatic alcohols to carboxylic acids without any additive. Mechanistic studies strongly support that the MOF‐stabilized coordination cage with perfluorinated ligands unleashes the full electrophilic potential of Pd2+ to dehydrogenate primary alcohols, without any base, and also to activate O2 for the radical oxidation to the aldehyde intermediate. This study opens the door to design catalytic perfluorinated complexes for challenging organic transformations, where an extremely high electrophilic metal site is required. [ABSTRACT FROM AUTHOR]

Developing efficient adsorbent materials is crucial for adsorption and separation to realize the purification of energy source and raw chemicals. Here, we report a novel and robust 3D In‐based MOF built up with fluorine‐functionalized ligands, QMOF‐2F, with improved separation properties of C2‐light hydrocarbons over methane at room temperature respect isoreticular non‐fluorinated MOF. QMOF‐2F shows a remarkable chemical stability in different solvents, including water, and pH (2–12). DFT calculations support the key role of fluorine‐functionalization on the improved performance of QMOF‐2F. [ABSTRACT FROM AUTHOR]

The low‐temperature water‐gas shift reaction (WGSR, CO+H2O ⇔ H2+CO2) is considered a very promising reaction ‐candidate for fuel cells‐ despite an efficient and robust catalyst is still desirable. One of the more prominent catalysts for this reaction is based on single Pt atoms (Pt1) on different supports, which are supposed to manifold the reaction by the accepted mechanism for the general WGSR, i. e. by addition of one H2O molecule to CO, with generation of CO2 and H2. Here we show, experimentally, that not one but two H2O molecules are added to CO on the Pt1 catalyst, as assessed by a combination of reactivity experiments with soluble Pt catalysts, kinetic and spectroscopic measurements, and finally by in‐operando single crystal X‐ray diffraction on a Pt1‐MOF, to visualize the formation of the hemiacetal intermediate on the solid catalytic site. These results confirm our previous DFT predictions and provide a paradigmatic shift in the assumed mechanism of the WGSR, which may open the debate if two H2O molecules are recurrently added during the WGSR, not only for Pt1 catalysts but also for other metal catalysts. [ABSTRACT FROM AUTHOR]

The reactions of LnIII ions with a versatile pyridyl-decorated dicarboxylic acid ligand lead to the formation of a series of novel three-dimensional (3D) Ln-MOFs, [Ln3(pta)4(Hpta)(H2O)]·xH2O (Ln = Dy (1), Eu (2), Gd (3), Tb (4), H2pta = 2-(4-pyridyl)-terephthalic acid, x = 6 for 1, 2.5 for 2, 1.5 for 3 and 2 for 4). The Ln3+ ions act as nine-coordinated muffin spheres, linking to each other to generate trinuclear {Ln3(OOC)6N2} SBUs, which are further extended to be interesting 3D topological architectures. To the best of our knowledge, the Dy-MOF exhibits zero-field single-molecule magnet (SMM) behaviour with the largest effective energy barrier among the previously reported 3D MOF-based Dy-SMMs. The combined analyses of a diluted sample (1@Y) and ab initio calculations demonstrate that the thermally assisted slow relaxation is mainly attributed to the single-ion magnetism. Furthermore, fluorescence measurements reveal that H2pta can sensitize EuIII and TbIII characteristic luminescence. [ABSTRACT FROM AUTHOR]

The exact chemical structure of non–crystallising natural products is still one of the main challenges in Natural Sciences. Despite tremendous advances in total synthesis, the absolute structural determination of a myriad of natural products with very sensitive chemical functionalities remains undone. Here, we show that a metal–organic framework (MOF) with alcohol–containing arms and adsorbed water, enables selective hydrolysis of glycosyl bonds, supramolecular order with the so–formed chiral fragments and absolute determination of the organic structure by single–crystal X–ray crystallography in a single operation. This combined strategy based on a biomimetic, cheap, robust and multigram available solid catalyst opens the door to determine the absolute configuration of ketal compounds regardless degradation sensitiveness, and also to design extremely–mild metal–free solid–catalysed processes without formal acid protons. Elucidation of the chemical structure of natural products constitutes one of the main challenges in Natural Sciences. Here, the authors show that an amino acid-based metal–organic framework exhibits hydrolase-like catalytic activity and crystallographic determination of the resulting products. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) are seen as promising candidates to overcome the fundamental limit of polymeric membranes, known as the so-called Robeson upper bound, which defines the best compromise between permeability and selectivity of neat polymeric membranes. To overcome this limit, the permeability of the filler particles in the MMM must be carefully matched with that of the polymer matrix. The present work shows that it is not sufficient to match only the permeability of the polymer and the dispersed phase, but that one should consider also the individual contributions of the diffusivity and the solubility of the gas in both components. Here we compare the gas transport performance of two different MMMs, containing the metal–organic framework CuNi-MOF in the rubbery Pebax®1657 and in the glassy poly(ether-ether-ketone) with cardo moiety, PEEK-WC. The chemical and structural properties of MMMs were investigated by means of FT-IR spectroscopy, scanning electron microscopy and EDX analysis. The influence of MOF on the mechanical and thermal properties of both polymers was investigated by tensile tests and differential scanning calorimetry, respectively. The MOF loading in Pebax®1657 increased the ideal H2/N2 selectivity from 6 to 8 thanks to an increased H2 permeability. In general, the MOF had little effect on the Pebax®165 membranes because an increase in gas solubility was neutralized by an equivalent decrease in effective diffusivity. Instead, the addition of MOF to PEEK-WC increases the ideal CO2/CH4 selectivity from 30 to ~48 thanks to an increased CO2 permeability (from 6 to 48 Barrer). The increase in CO2 permeability and CO2/CH4 selectivity is maintained under mixed gas conditions. [ABSTRACT FROM AUTHOR]

Complexation of dysprosium(III) ions with a multidentate hydrazone ligand, N-[(E)-pyridin-2-ylmethylideneamino]pyridine-2-carboxamide (L), in the presence of different β-diketonate coligands, leads to the formation of two novel DyIII dimers, with formulas Dy2(BTFA)4(L)2 (1) and Dy2(TTA)4(L)2 (2) (BTFA = 3-benzoyl-1,1,1-trifluoroacetone and TTA = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate). They exhibit slightly different coordination geometries around DyIII centers and discrepant binuclear motifs – as a result of altering the β-diketonate coligands – which has an impact on the magnetic interactions between metal centers, the local tensor of anisotropy on each DyIII site and their relative orientations, therefore contributing to distinct magnetization dynamics. Compared to 2, complex 1 exhibits a more significant slow magnetic relaxation of SMM behavior in the absence of a dc field. The QTM effect is effectively repressed under a static field, resulting in the energy barriers of 57 K for 1 and 38 K for 2. Ab initio calculations clarify that, strong single-ion magnetic anisotropies exist in both complexes, whereas intermetallic ferromagnetic interaction and antiferromagnetic interaction are observed in 1 and 2, respectively, therefore resulting in dissimilar magnetization dynamics. [ABSTRACT FROM AUTHOR]

A family of four mononuclear DyIII β‐diketonate complexes with formulas [Dy(tmhd)3(Br2‐bpy) (1), [Dy(tmhd)3(Br‐bpy)] (2), [Dy(tmhd)3(dppz)] (3), and [Dy(tmhd)3(mcdpq)] (4) (tmhd=2,2,6,6‐tetramethyl‐3,5‐heptanedione, Br2‐bpy=5,5′‐dibromo‐2,2′‐bipyridine, Br‐bpy=5‐bromo‐2,2′‐bipyridine, dppz=dipyrido [3,2‐a:2′,3′‐c]phenazine, mcdpq=2‐methoxyl‐3‐cyanodipyrido[3,2‐f:2,3′‐h]quinoxaline) were prepared by modifying the capping N‐donor coligands. DyIII centers in these complexes feature an N2O6 octacoordinate environment with distorted square‐antiprismatic D4d symmetry. Magnetic investigations evidenced single‐ion magnet behavior in all complexes with energy barriers Ueff of 42.10 (1), 61.47, (2), 77.53 (3), and 2.51 K (4) in the absence of static field, as well as 206.03 (1), 224.13 (2), 247.76 (3), and 49.70 K (4) under applied dc field (Hdc=1500 Oe for 1 and 2; Hdc=1200 Oe for 3 and 4). The different natures of the N‐donor ligands induce changes in both the coordination geometry and their intermolecular interactions, which severely impact their magnetic dynamics. The disparities in their magnetic behaviors and the uniaxial anisotropies are also explained and substantiated by theoretical calculations. Cap variations: A combination of electron‐donating β‐diketonate ligands and different capping N‐donor coligands led to a family of four mononuclear DyIII complexes exhibiting nearly identical D4d symmetry but differing magnetic dynamics, which were elucidated by a combination of magnetic investigations and ab initio calculations. [ABSTRACT FROM AUTHOR]

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The presence of residual organic dyes in water resources or wastewater treatment systems, derived mainly from effluents of different industries, is a major environmental problem with no easy solution. Herein, an ecofriendly, water‐stable metal–organic framework was prepared from a derivative of the natural amino acid l‐serine. Its functional channels are densely decorated with highly flexible l‐serine residues bearing hydroxyl groups. The presence of such a flexible and functional environment within the confined environment of the MOF leads to efficient removal of different organic dyes from water: Pyronin Y, Auramine O, Methylene Blue and Brilliant Green, as unveiled by unprecedented snapshots offered by single‐crystal X‐ray diffraction. This MOF enables highly efficient water remediation by capturing more than 90 % of dye content, even at very low concentrations such as 10 ppm, which is similar to those usually found in industrial wastewaters. Remarkably, the removal efficiency is improved in simulated contaminated mineral water with multiple dyes. Multidye capture: A highly crystalline metal–organic framework, derived from the amino acid l‐serine, captures efficiently different organic dyes at very low concentration, even in the presence of multiple dyes (see figure). In addition, single‐crystal X‐ray diffraction offered unprecedented snapshots of the dye‐capture process. [ABSTRACT FROM AUTHOR]