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We use the free radical polymerization initiator 4,40-azobis(cyanovaleric acid) coordinated to the open metal sites of metal-organic frameworks (MOFs) to give rise to highly uniform MOF/polymer hybrids.We demonstrate this strategy on two robust zirconium MOFs (NU-1000 and MOF- 808), which are the most effective catalysts for degradation of chemical warfare nerve agents. The resulting hybrid materials maintain their hydrolytic catalytic activity and have substantially improved adhesion to polypropylene and activated carbon textile fibers, yielding highly robust MOF/polymer/textile hybrid systems. These composites are suitable for the green production of active protective clothing and filters capable of detoxifying organophosphorus warfare agents., National Science Center (NCN) of Poland 2020/37/N/ST5/01107 UMO-2014/14/E/ST5/00652, Polish NAWA Agency under the Ulam Fellowship program PPN/ULM/2020/1/00218, University of Warwick, MCIN/AEI PID2020-113608RB-I00, UK Research & Innovation (UKRI), Biotechnology and Biological Sciences Research Council (BBSRC) EP/T015063/1, Engineering & Physical Sciences Research Council (EPSRC), European Commission, Birmingham Science City Advanced Materials Project 1 - Advantage West Midlands (AWM) Birmingham Science City Advanced Materials Project 2 - Advantage West Midlands (AWM)

Two model porphyrin metal-organic frameworks were used for the incorporation of Rh(i) species by a post-synthetic metallation under mild conditions. As a result, new rhodium MOFs (Rh/MOFs), Rh/PCN-222 and Rh/NU-1102, were synthesized and structurally characterized. To illustrate the potential of this catalytic platform, we use Rh/MOFs as phosphine-free heterogeneous catalysts in the hydrogenation of unsaturated hydrocarbons under mild reaction conditions (30 °C and 1 atm H2). We found that for our Rh/MOFs an activation step is required during the first run of the catalytic process. The presence of Rh-CO moieties allowed us to monitor the activation pathway of the catalyst under a H2 atmosphere, by in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). After activation, the catalyst remains highly active during the subsequent catalytic cycles. This simple post-synthetic modification approach presents new possibilities for the utilization of Rh-based catalytic systems with robust porphyrin-based MOFs as supports.

Layered hybrid halide perovskites are known to be more environmentally stable than their 3D analogues. The enhanced stability is particularly relevant for Dion–Jacobson-type layered perovskites due...

In this study, we present a complementary approach for obtaining an effective drug, based on acriflavine (ACF) and zirconium-based metal-organic frameworks (MOFs), against SARS-CoV-2. The experimental results showed that acriflavine inhibits the interaction between viral receptor-binding domain (RBD) of spike protein and angiotensin converting enzyme-2 (ACE2) host receptor driving viral cell entry. The prepared ACF@MOF composites exhibited low (MOF-808 and UiO-66) and high (UiO-67 and NU-1000) ACF loadings. The drug release profiles from prepared composites showed different release kinetics depending on the local pore environment. The long-term ACF release with the effective antiviral ACF concentration was observed for all studied ACF@MOF composites. The density functional theory (DFT) calculations allowed us to determine that π-π stacking together with electrostatic interaction plays an important role in acriflavine adsorption and release from ACF@MOF composites. The molecular docking results have shown that acriflavine interacts with several possible binding sites within the RBD and binding site at the RBD/ACE2 interface. The cytotoxicity and ecotoxicity results have confirmed that the prepared ACF@MOF composites may be considered potentially safe for living organisms. The complementary experimental and theoretical results presented in this study have confirmed that the ACF@MOF composites may be considered a potential candidate for the COVID-19 treatment, which makes them good candidates for clinical trials.

A hybrid nanocarbon receptor consisting of a calix[4]arene and a bent oligophenylene loop ("molecular squid"), was obtained in an efficient, scalable synthesis. The system contains an electron-rich cavity with an adaptable shape, which can serve as a host for electron deficient guests, such as diquat, 10-methylacridinium, and anthraquinone. The new receptor forms inclusion complexes in the solid state and in solution, showing a dependence of the observed binding strength on the shape of the guest species and its charge. The interaction with the methylacridinium cation in solution was interpreted in terms of a 2:1 binding model, with K11 = 5.92(7) × 103 M-1. The solid receptor is porous to gases and vapors, yielding an uptake of ca. 4 mmol/g for methanol at 293 K. In solution, the receptor shows cyan fluorescence (λmaxem = 485 nm, ΦF = 33%), which is partly quenched upon binding of guests. Methylacridinium and anthraquinone adducts show red-shifted emission in the solid state, attributable to the charge-transfer character of these inclusion complexes.

Recent developments in porous coordination polymers make them attractive candidates for various potential applications including systems for controlled drug administration. Drug delivery systems based on metal–organic frameworks (MOF) are usually constructed either by non-covalent adsorption of drug molecules inside the pores of the material or by covalent modification of organic linkers. Herein, we propose alternative method for incorporation of drug molecules inside MOFs by binding them to the metal node using Solvent-Assisted Ligand Incorporation (SALI). We tested NU-1000 platform which contains 8-connecting Zr6-nodes, which can bind up to 4 carboxylate-based ligands. Using SALI technique we successfully anchored three model drug molecules containing carboxylate groups: ketoprofen, nalidixic acid and levofloxacin with drug loadings reaching 30 wt% yielding guest@NU-1000 materials. Our study shows that NU-1000 is stable in phosphate concentrations present in blood plasma, whereas drug molecules can be released from guest@NU-1000 under these conditions without decomposition of the MOF framework. We also observed that the drug release kinetics strongly depends on the size of the guest molecules.

Selective separation of gases/vapors with similar physicochemical properties involves energetically costly distillation processes. Alternative separation processes based on shape-selective molecular sieving, taking place on porous frameworks (or membranes), are less energy demanding but require an optimal balance between selectivity and diffusion kinetics (permeability). Herein, we report a rational strategy to select an optimal soft noncovalent microporous material (NPM) suitable for the low-energy separation of C6-hydrocarbons with kinetic diameters in the range of 4.3–6.3 A. This strategy is based on a Cambridge Structural Database search of diamondoid NPMs with a low packing factor, leading to the selection of an oxidotetrazinc cluster based diamondoid NPM network named DiaMM-1 containing tetrahedral voids of 336 A3 (tetrahedron insphere diameter of 5.8 A accessible through 8.2 A triangular windows) suitable for this separation. Based on this result the fluorinated analogue DiaMM-2 was designed and sy...

Dion-Jacobson (DJ) iodoplumbates based on 1,4-phenylenedimethanammonium (PDMA) have recently emerged as promising light absorbers for perovskite solar cells. While PDMA is one of the simplest aromatic spacers potentially capable of forming a DJ structure based on (PDMA)An-1 Pbn I3n+1 composition, the crystallographic proof has not been reported so far. Single crystal structure of a DJ phase based on PDMA is presented and high-field solid-state NMR spectroscopy is used to characterize the structure of PDMA-based iodoplumbates prepared as thin films and bulk microcrystalline powders. It is shown that their atomic-level structure does not depend on the method of synthesis and that it is ordered and similar for all iodoplumbate homologues. Moreover, the presence of lower (n) homologues in thin films is identified through UV-Vis spectroscopy, photoluminescence spectroscopy, and X-ray diffraction measurements, complemented by cathodoluminescence mapping. A closer look using cathodoluminescence shows that the micron-scale microstructure corresponds to a mixture of different layered homologues that are well distributed throughout the film and the presence of layer edge states which dominate the emission. This work therefore determines the formation of DJ phases based on PDMA as the spacer cation and reveals their properties on a multi-length scale, which is relevant for their application in optoelectronics.

The conversion of 2,4,6-tris(4′-bromophenyl)-1,3,5-triazine to the respective triboronic acid was successfully accomplished by a simple triple Br/Li exchange followed by boronation. Further dehydrative condensation reactions with 2,3,6,7,10,11-hexahydroxytriphenylene or 2,3,6,7-tetrahydroxy-9,10-dilalkylanthracenes (R = Me, Et) resulted in materials featuring good porosity and sorption properties with the nitrogen uptake exceeding 500 cm3/g (STP) and SBET up to 1267 m2/g (T = 77.2 K). In addition, simple dehydration of this compound was employed for the preparation of a hybrid 2D COF composed of triazine, boroxine, and benzene rings. The formation of materials was confirmed by the IR analysis and NMR studies on water-decomposed samples. All obtained COFs exhibit high thermal stability with decomposition temperatures in the range of 400–600 °C. They also show quite different morphology ranging from regular 0.5–4 μm spherical and ellipsoidal clusters to 5–12 μm bent rodlike particles. The PXRD studies suppo...

A model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state was investigated via combined crystallographic and spectroscopic techniques contributed substantially by theoretical modelling. The complex appeared to exhibit luminescence thermochromism, i.e. red phosphorescence at room temperature which changes to green when lowering the temperature to 90 K. The low-energy emissive state was assigned as a cluster-centred triplet, 3CC. The emission from this state predicted in TDDFT (~635 nm) matches the experimental red band observed at 660&ndash, 715 nm. In contrast, the nature of the high-energy &ldquo, green&rdquo, band was less straightforward. The next reached cluster-centred triplet excited state occurred to be energetically close to the experimental value of ~545 nm. The two excited states also exhibit significant metal-to-ligand and ligand-to-metal charge transfer characteristics, especially for solid-state distorted geometries. In both cases the cluster core was expected to become notably contracted when compared to the ground state. Time-resolved photocrystallographic results supported the computationally predicted core contraction upon excitation. Additionally, the differences between the spectroscopic behaviour of the related tetra- and hexanuclear copper(I) complexes, Cu4 and Cu6 (i.e., [(PhCO2)6Cu6]) in the crystalline state were discussed and examined. It appeared that crystal packing may constitute an important factor as far as the lack of luminescence thermochromism in the latter case is concerned. Synopsis: Structure&ndash, property relationships characterising a model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state were investigated via combined crystallographic and spectroscopic techniques contributed by theoretical modelling, and compared with the properties of the related [(PhCO2)6Cu6] (Cu6) complex.

Selective separation of gases/vapors with similar physicochemical properties involves energetically costly distillation processes. Alternative separation processes based on shape-selective molecular sieving, taking place on porous frameworks (or membranes), are less energy demanding but require an optimal balance between selectivity and diffusion kinetics (permeability). Herein, we report a rational strategy to select an optimal soft noncovalent microporous material (NPM) suitable for the low-energy separation of C

The efficient capture and storage of radioactive iodine (129I or 131I), which can be formed during nuclear energy generation or nuclear waste storage, is of paramount importance. Herein, we present highly efficient aerogels for reversible iodine capture, namely, porous silsesquioxane–imine frameworks (PSIFs), constructed by condensation of octa(3-aminopropyl)silsesquioxane cage compound and selected multitopic aldehydes. The resulting PSIFs are permanently porous (Brunauer–Emmet–Teller surface areas up to 574 m2/g), thermally stable, and present a combination of micro-, meso-, and macropores in their structures. The presence of a large number of imine functional groups in combination with silsesquioxane cores results in extremely high I2 affinity with uptake capacities up to 485 wt %, which is the highest reported to date. Porous properties can be controlled by the strut length and rigidity of linkers. In addition, PSIF-1a could be recycled at least four times while maintaining 94% I2 uptake capacity. Kin...

Chemical warfare agents containing phosphonate ester bonds are among the most toxic chemicals known to mankind. Recent global military events, such as the conflict and disarmament in Syria, have brought into focus the need to find effective strategies for the rapid destruction of these banned chemicals. Solutions are needed for immediate personal protection (for example, the filtration and catalytic destruction of airborne versions of agents), bulk destruction of chemical weapon stockpiles, protection (via coating) of clothing, equipment and buildings, and containment of agent spills. Solid heterogeneous materials such as modified activated carbon or metal oxides exhibit many desirable characteristics for the destruction of chemical warfare agents. However, low sorptive capacities, low effective active site loadings, deactivation of the active site, slow degradation kinetics, and/or a lack of tailorability offer significant room for improvement in these materials. Here, we report a carefully chosen metal-organic framework (MOF) material featuring high porosity and exceptional chemical stability that is extraordinarily effective for the degradation of nerve agents and their simulants. Experimental and computational evidence points to Lewis-acidic Zr(IV) ions as the active sites and to their superb accessibility as a defining element of their efficacy.

An isoreticular series of metal-organic frameworks (MOFs) with the ftw topology based on zirconium oxoclusters and tetracarboxylate linkers with a planar core (NU-1101 through NU-1104) has been synthesized employing a linker expansion approach. In this series, NU-1103 has a pore volume of 2.91 cc g(-1) and a geometrically calculated surface area of 5646 m(2) g(-1), which is the highest value reported to date for a zirconium-based MOF and among the largest that have been reported for any porous material. Successful activation of the MOFs was proven based on the agreement of pore volumes and BET areas obtained from simulated and experimental isotherms. Critical for practical applications, NU-1103 combines for the first time ultrahigh surface area and water stability, where this material retained complete structural integrity after soaking in water. Pressure range selection for the BET calculations on these materials was guided by the four so-called "consistency criteria". The experimental BET area of NU-1103 was 6550 m(2) g(-1). Insights obtained from molecular simulation suggest that, as a consequence of pore-filling contamination, the BET method overestimates the monolayer loading of NU-1103 by ∼16%.

Solvent-assisted ligand incorporation (SALI) is useful for functionalizing the channels of metal-organic framework (MOF) materials such as NU-1000 that offer substitutionally labile zirconium(IV) coordination sites for nonbridging ligands. Each of the 30 or so previous examples relied upon coordination of a carboxylate ligand to achieve incorporation. Here we show that, with appropriate attention to ligand/node stoichiometry, SALI can also be achieved with phosphonate-terminated ligands. Consistent with stronger M(IV) coordination of phosphonates versus carboxylates, this change extends the pH range for retention of incorporated ligands. The difference in coordination strength can be exploited to achieve stepwise incorporation of pairs of ligands-specifically, phosphonates species followed by carboxylate species-without danger of displacement of the first ligand type by the second. Diffuse reflectance infrared Fourier-transform spectroscopy suggests that the phosphonate ligands are connected to the MOF node as RPO2(OH)¯ species in a moiety that leaves a base-accessible -OH moiety on each bound phosphonate.

A novel organozinc initiator with a clear mechanistic signature for organic radical reactions has been developed., This paper reports a series of comparative experiments on the activity of carbon- and oxygen-centred radical species in a model reaction of the radical addition of THF to imines mediated by a series of zinc alkyl/air reaction systems. The study strongly contradicts the notion that generally R˙ radicals are the initiating species in organic reactions mediated by RnM/air systems, and simultaneously demonstrates that oxygen-centred radical species are the key intermediates responsible for the initiation process. In addition, a new efficient RZn(L)/air initiating system for radical organic reactions exampled by a model reaction of radical addition of THF to imines is developed. Moreover, the isolation and structural characterization of the first zinc alkylperoxide supported by a carboxylate ligand, [Zn4(μ3-OOtBu)3(μ4-O)(O2CEt)3]2, as well as the novel octanuclear zinc oxo(alkoxide) aggregate with entrapped O–THF species, [Zn4(μ4-O)(μ3-2-O–THF)(O2CEt)5]2, provide clear mechanistic signatures for the mode of function of the RZn(O2CR′)/air system.

Experimentally refined crystal structures for metal–organic frameworks (MOFs) often include solvent molecules and partially occupied or disordered atoms. This creates a major impediment to applying high-throughput computational screening to MOFs. To address this problem, we have constructed a database of MOF structures that are derived from experimental data but are immediately suitable for molecular simulations. The computation-ready, experimental (CoRE) MOF database contains over 4700 porous structures with publically available atomic coordinates. Important physical and chemical properties including the surface area and pore dimensions are reported for these structures. To demonstrate the utility of the database, we performed grand canonical Monte Carlo simulations of methane adsorption on all structures in the CoRE MOF database. We investigated the structural properties of the CoRE MOFs that govern methane storage capacity and found that these relationships agree well with those derived recently from a...

Electrophoretic deposition (EPD) is used to assemble metal-organic framework (MOF) materials in nano- and micro-particulate, thin-film form. The flexibility of the method is demonstrated by the successful deposition of 4 types of MOFs: NU-1000, UiO-66, HKUST-1, and Al-MIL-53. Additionally, EPD is used to pattern the growth of NU-1000 thin films that exhibit full electrochemical activity.

A family of group 13 organometallic macrocyclic phthalates [(MMe2)2(μ-O2C)2-1,2-C6H4]2 (where M = Al (1), Ga (2), In (3)) is prepared, and the reactivity of these homologous carboxylates toward various monodentate Lewis bases is investigated. The studies provide the first structurally characterized methylindium [{(Me2In)(μ-O2C)2-1,2-C6H4}{Me2In(THF)}]n (4) and methylaluminum [{(Me2Al)(μ-O2C)2-1,2-C6H4}{Me2Al(py-Me)}]n (5) 1D coordination polymers stabilized by dicarboxylate ligands as a result of disruption of the parent tetranuclear macrocyclic structural motifs in 3 and 1 by the incoming donor ligands. The molecular and crystal structures of the reported compounds are examined by spectroscopic studies and single-crystal X-ray diffraction.

Metal-organic frameworks (MOFs) are hybrid porous materials with many potential applications, which intimately depend on the presence of chemical functionality either at the organic linkers and/or at the metal nodes. Functionality that cannot be introduced into MOFs directly via de novo syntheses can be accessed through post-synthesis modification (PSM) on the reactive moieties of the linkers and/or nodes without disrupting the metal-linker bonds. Even more intriguing methods that go beyond PSM are herein termed building block replacement (BBR) which encompasses (i) solvent-assisted linker exchange (SALE), (ii) non-bridging ligand replacement, and (iii) transmetalation. These one-step or tandem BBR processes involve exchanging key structural components of the MOF, which in turn should allow for the evolution of protoMOF structures (i.e., the utilization of a parent MOF as a template) to design MOFs composed of completely new components, presumably via single crystal to single crystal transformations. The influence of building block replacement on the stability and properties of MOFs will be discussed, and some insights into their mechanistic aspects are provided. Future perspectives providing a glimpse into how these techniques can lead to various unexplored areas of MOF chemistry are also presented.

Metall-organische Geruste (MOFs) sind Hybridmaterialien, die anhaltendes Interesse auf sich ziehen – nicht zuletzt wegen vielfaltiger moglicher Anwendungen, von der Gastrennung uber die Katalyse bis hin zum Sammeln von Licht. Allerdings ist die De-novo-Synthese von MOFs mit gewunschten Eigenschaften nicht immer einfach: unerwunschte Topologien konnen entstehen, die Loslichkeit von Vorstufen kann zu gering sein, und die Funktionalitat wichtiger Netzwerkkomponenten kann verlorengehen. Mit einem neuen Ansatz – dem losungsmittelunterstutzten Linker-Austausch (“solvent-assisted linker exchange”, SALE) – lassen sich diese Probleme umgehen, und tatsachlich wurden mit SALE bereits verschiedene MOF-Materialien erzeugt, die durch direkte Syntheseverfahren nicht erhaltlich waren. Unsere Ubersicht beschreibt Forschungsergebnisse uber MOFs, die erst durch SALE moglich gemacht wurden, und diskutiert Studien, die das Verstandnis dieses Verfahrens verbessert und sein Anwendungsgebiet erweitert haben.

A uniform and crack-free metalorganic framework (MOF) thin film composed of free-standing acicular nanorods was grown on a transparent conducting glass substrate. The MOF thin film exhibits electrochromic switching between yellow and deep blue by means of a one-electron redox reaction at its pyrene-based linkers. The rigid MOF stabilizes the radical cations of the pyrene linkers at positive applied potential, resulting in the reversible color change of the MOF film. The regular and uniform channels of the MOF allow ions to migrate through the entire film. The MOF thin film thus exhibits a remarkable color change and rapid switching rate.

A new functionalization technique, solvent-assisted ligand incorporation (SALI), was developed to efficiently incorporate carboxylate-based functionalities in the Zr-based metal-organic framework, NU-1000. Unlike previous metal node functionalization strategies, which utilize dative bonding to coordinatively unsaturated metal sites, SALI introduces functional groups as charge compensating and strongly bound moieties to the Zr6 node. Utilizing SALI, we have efficiently attached perfluoroalkane carboxylates of various chain lengths (C1-C9) on the Zr6 nodes of NU-1000. These fluoroalkane-functionalized mesoporous MOFs, termed herein SALI-n, were studied experimentally and theoretically as potential CO2 capture materials.

Solvent-assisted linker exchange (SALE) was performed on a pillared-paddlewheel metal–organic framework (MOF), SALEM-5, to achieve incorporation of longer linkers into the material. The 9-A meso-1,2-di(4-pyridyl)-1,2-ethanediol pillar of SALEM-5 was successfully replaced by 11-A, 14-A, and 17-A pillars to generate daughter MOFs SALEM-6, SALEM-7, and SALEM-8. The daughter frameworks possess more open cages, as was demonstrated by structural modeling from the powder X-ray diffraction patterns, and larger solvent accessible space, as was demonstrated by thermogravimetric analysis. Finally, a study was performed to examine the effect of pKa of monoprotonated dipyridyl pillars (as an indicator of the Zn–L bond strength) on the outcome of SALE.

Control over catenation in a pillared paddlewheel metal–organic framework was achieved via solvent-assisted linker exchange. The linker exchange was demonstrated on the noncatenated structure of DO-MOF, by using 4,4′-bipyridine (L4) and 4,4′-azobis(pyridine) (L5) as linkers, leading to noncatenated materials SALEM-3 and SALEM-4. The de novo synthesized analogues of SALEM-3 and SALEM-4 can only be obtained as 2-fold interpenetrated frameworks. The reaction progress of the linker exchange was monitored by NMR spectroscopy, and structure and framework catenation were characterized by powder X-ray diffraction and thermogravimetric methods.

International audience; A new synthetic procedure was developed to obtain a novel mononuclear chiral square-pyramidal (acetato) bis(aminoalkoxido) Mn-III complex from a heterometallic Zn-II/Mn-II system with a crucial role for O-2 in the process. The resulting compound was characterized spectroscopically and crystallo-graphically, and its magnetic properties were determined. The MnIII ion exhibits magnetic anisotropy with a zero-field splitting D parameter equal to -2.95 cm(-1).

The octet-compliant group 13 organometallics with highly polarized bonds in the metal coordination sphere exhibit a significant tendency to maximize their coordination number through the formation of adducts with a wide range of neutral donor ligands or by self-association to give aggregates containing tetrahedral and higher coordinated aluminium centres, and even in some cases molecular complexes equilibrate with ionic species of different coordination numbers of the metal centre. This work provides a comprehensive overview of the structural chemistry landscape of the group 13 carboxylates. Aside from a more systematic approach to the general structural chemistry of the title compounds, the structure investigations of [R2M(μ-O2CPh)]2-type benzoate complexes (where M = B, Al and Ga) and their Lewis acid–base adducts [(R2M)(μ-O2CPh)(py-Me)] are reported. DFT calculations were also performed to obtain a more in-depth understanding of both the changes in the bonding of group 13 organometallic carboxylate adducts with a pyridine ligand.

A zeolitic imidazolate framework material of SOD topology possessing primarily unsubstituted imidazolate (im) linkers has been synthesized via solvent-assisted linker exchange (SALE) of ZIF-8. The structure of the new material, SALEM-2, has been confirmed through (1)H NMR and powder and single-crystal X-ray diffraction. SALEM-2 is the first example of a porous Zn(im)(2) ZIF possessing a truly zeolitic topology that can be obtained in bulk quantities. Upon treatment with n-butyllithium, the open analogue exhibits Brønsted base catalysis that cannot be accomplished by the parent material ZIF-8. Additionally, it displays a different size cutoff for uptake and release of molecular guests than does ZIF-8.

An atom-efficient and mild synthesis of a series of oxozinc carboxylates [Zn(4)(μ(4)-O)(O(2)CR)(6)] [where R = Ph (2a), p-PhC(6)H(4) (2b), p-MeC(6)H(4) (2c), and p-MeSC(6)H(4) (2d)] from well-defined alkylzinc precursors and H(2)O is described. The molecular and crystal structures of the resulting complexes have been determined by single-crystal X-ray diffraction. A closer examination of their crystal structure provides a direct picture of the effect of the nature of substituents on the molecular self-assembly of the octahedral oxozinc through noncovalent interactions. It was revealed that these discrete oxozinc clusters can form diverse types of noncovalent assemblies ranging from structures representing zeolitic topologies in the case of 2a to soft porous materials with gated voids or open channels for the remaining molecular clusters.

Thin films of the metal-organic framework (MOF) NU-1000 were grown on conducting glass substrates. The films uniformly cover the conducting glass substrates and are composed of free-standing sub-micrometer rods. Subsequently, atomic layer deposition (ALD) was utilized to deposit Co(2+) ions throughout the entire MOF film via self-limiting surface-mediated reaction chemistry. The Co ions bind at aqua and hydroxo sites lining the channels of NU-1000, resulting in three-dimensional arrays of separated Co ions in the MOF thin film. The Co-modified MOF thin films demonstrate promising electrocatalytic activity for water oxidation.

"Breathing" metal-organic frameworks (MOFs) are an emerging class of soft porous crystals (SPCs) with potential for high working capacity for gas storage applications. However, most breathing MOFs have low stability and/or low surface area. Here we report a water-stable, high surface area, breathing MOF of ftw topology, NU-1105. While Zr6-oxo clusters as nodes introduce water stability in NU-1105, its high surface area and breathing character stem from its pyrene-based tetracarboxylate (Py-FP) linkers, in which the fluorene units (F) in the FP "arms" play a key role in promoting breathing behavior. During gas sorption studies, the "closed pore" (cp) ↔ "open pore" (op) transition of NU-1105 occurs at a propane pressure of ∼3 bar. At 1 bar, NU-1105 is in its cp form and adsorbs less propane than it would in its op form, highlighting improved working capacity. In situ powder X-ray diffraction during propane sorption was used to track the cp ↔ op transition, and molecular modeling was used to elucidate the structure of the op and cp forms of NU-1105. According to TD-DFT calculations, the proposed conformations of the Py-FP linkers in the op and cp forms are consistent with the measured excitation and emission spectra of the op and cp forms of NU-1105. Similar structural transitions are also observed in the porphyrinic MOF NU-1104 depending on the identity of the porphyrin core; we observed breathing behavior if the constituent Por-PTP linker is nonmetalated.

The availability of efficient hydrogen evolution reaction (HER) catalysts is of high importance for solar fuel technologies aimed at reducing future carbon emissions. Even though Pt electrodes are excellent HER electrocatalysts, commercialization of large-scale hydrogen production technology requires finding an equally efficient, low-cost, earth-abundant alternative. Here, high porosity, metal-organic framework (MOF) films have been used as scaffolds for the deposition of a Ni-S electrocatalyst. Compared with an MOF-free Ni-S, the resulting hybrid materials exhibit significantly enhanced performance for HER from aqueous acid, decreasing the kinetic overpotential by more than 200 mV at a benchmark current density of 10 mA cm−2. Although the initial aim was to improve electrocatalytic activity by greatly boosting the active area of the Ni-S catalyst, the performance enhancements instead were found to arise primarily from the ability of the proton-conductive MOF to favourably modify the immediate chemical environment of the sulfide-based catalyst., Hydrogen evolution technologies for a future carbon-free energy economy require efficient catalysts which can be implemented on a large scale. Here, the authors prepare a composite electrode from readily available elements, whereby a metal-organic framework boosts catalytic performance by enabling rapid proton transport.

The installation of ferrocene molecules within the wide-channel metal-organic framework (MOF) compound, NU-1000, and subsequent configuration of the modified MOF as thin-film coatings on electrodes renders the MOF electroactive in the vicinity of the ferrocenium/ferrocene (Fc(+)/Fc) redox potential due to redox hopping between anchored Fc(+/0) species. The observation of effective site-to-site redox hopping points to the potential usefulness of the installed species as a redox shuttle in photoelectrochemical or electrocatalytic systems. At low supporting electrolyte concentration, we observe bias-tunable ionic permselectivity; films are blocking toward solution cations when the MOF is in the ferrocenium form but permeable when in the ferrocene form. Additionally, with ferrocene-functionalized films, we observe that the MOF's pyrene-based linkers, which are otherwise reversibly electroactive, are now redox-silent. Linker electroactivity is fully recovered, however, when the electrolyte concentration is increased 10-fold, that is, to a concentration similar to or exceeding that of an anchored shuttle molecule. The findings have clear implications for the design and use of MOF-based sensors, electrocatalysts, and photoelectrochemical devices.

Organozinc hydroxides ,R ZnOH, possessing the proton-reactiv ea lkylzinc group and the CO2-reactive Zn¢OH group, represent an intriguing group of organometallic pre- cursors for the synthesis of novel zinc carbonates .C ompre- hensive experimental and computational investigations on 1) solution an ds olid-stat eb ehavior of tBuZnOH (1 )s pecies in the presence of Lewis bases, namely ,T HF and 4-methyl- pyridine ;2 )s tep-by-step sequence of the reactio nb etween 1 and CO2 ;a nd 3) the effect of ad onor ligand and/or an excess of tBu2Zn as an external proto na cceptor on the reac- tion course are reported. DFT calculations for the insertion of carbon dioxide into the dinuclea ra lkylzinc hydroxide 12 are fully consisten tw ith 1 HN MR spectroscopy studies and indi- cate that this process is am ultistep reaction, in which the in- sertion of CO2 seems to be the rate-determining step. More- over ,D FT studies show that the mechanism of the rearrange- ment between key intermediates, that is, the primary alkyl- zinc bicarbonate with ap roximal position of hydrogen and the secondary alkylzinc bicarbonate with ad istal positio no f hydrogen, most likely proceeds through internal rotatio no f the dinuclear bicarbonate.

Crystallization of Me3In from hexane solution at ambient temperature allows for the isolation of a new phase that cannot be obtained by classical sublimation routes. The crystal structure analysis revealed that this new polymorph of Me3In crystallizes in the rhombohedral space group R3 h. The primary structural effect of the In-CH3‚‚‚In intermolecular interactions results in the formation of cyclic hexamers with 12-membered (InC)6 rings of an extended-chair conformation. The shortest intermolecular In‚‚‚C contact is 3.028(4) A with In‚‚‚H distances between 2.74 and 2.79 A. The hexamers are further linked by longer In-CH3‚‚‚In bridges into the 3D network. In addition, the tetragonal form of Me3In was redetermined at 100 K. The presented results demonstrate that the impact of both crystallization conditions and the character of intermolecular forces on clustering events is evident. Finally, the network topology of a family of the group 13 trimethyls is analyzed and correlated.

The X-ray structure analysis of the alkylaluminum and -indium compounds derived from methyl thiosalicylate, Me2Al(SC6H4-2-CO2Me) and [Me2In(µ-SC6H4-2-CO2Me)]2, revealed that the intermolecular S···C(π) interaction between the Al–S thiolate units and the ester π-surface can effectively compete with the hypercoordinate sulfur–metal dative bond. The former compound exists as the noncovalently bonded

The reaction of (t)Bu(2)Zn with water was investigated which led to isolation of the novel hexameric tert-butylzinc hydroxide. The resulting zinc hydroxide cluster appears to be an ideal predesigned single-source precursor which decomposes smoothly in one step at only ca. 120 °C into ZnO nanoparticles.

Alkylzinc alkoxides, (RZnOR')4 ,h ave received much attention as efficient precursors of ZnO nanocrystals (NCs), and their "Zn4O4 "h eterocubane core has been regarded as a" preorganized ZnO". Ac omprehensive investigation of the synthesis and characterization of an ew family of tert-butyl- (tert-butoxy)zinc hydroxides, ((tBu)4Zn4(m3-OtBu)x(m3-OH)4¢x ), as model single-source precursors of ZnO NC si sr eported. The direct reaction between well-defined (tBuZnOH)6 (16) and (tBuZnOtBu)4 (24 )i nv arious molar ratios allows the isola- tion of new mixed cubane aggregates as crystalline solids in ah igh yield :( ( tBu)4Zn4(m3-OtBu)3(m3-OH)) (3), ((tBu)4Zn4(m3- OtBu)2(m3-OH)2 )( 4), ((tBu)4Zn4(m3-OtBu)(m3-OH)3 )( 5). The re- sulting products were characterize di ns olution by 1 HN MR and IR spectroscopy ,a nd in the soli ds tate by single-crystal X-ray diffraction .T he thermal transformations of 2-5 were monitored by in situ variable-temperature powder X-ray dif- fraction and thermogravimetric measurements. The investi- gation showe dt hat the Zn¢ OH groups appeared to be ad e- sirable feature for the solid-state synthesis of ZnO NCs that significantly decreased the decomposition temperature of crystalline precursors 3-5.

Metal–organic frameworks (MOFs) are hybrid porous materials with many potential applications, which intimately depend on the presence of chemical functionality either at the organic linkers and/or at the metal nodes. Functionality that cannot be introduced into MOFs directly via de novo syntheses can be accessed through post-synthesis modification (PSM) on the reactive moieties of the linkers and/or nodes without disrupting the metal–linker bonds. Even more intriguing methods that go beyond PSM are herein termed building block replacement (BBR) which encompasses (i) solvent-assisted linker exchange (SALE), (ii) non-bridging ligand replacement, and (iii) transmetalation. These one-step or tandem BBR processes involve exchanging key structural components of the MOF, which in turn should allow for the evolution of protoMOF structures (i.e., the utilization of a parent MOF as a template) to design MOFs composed of completely new components, presumably via single crystal to single crystal transformations. The influence of building block replacement on the stability and properties of MOFs will be discussed, and some insights into their mechanistic aspects are provided. Future perspectives providing a glimpse into how these techniques can lead to various unexplored areas of MOF chemistry are also presented.

The synthesis of a permanently porous pillared-paddlewheel metal–organic framework (MOF) was achieved through transmetalation of Zn(II) with Ni(II). The MOF can be treated with liquid water, leading to the reversible displacement of 50% of its pillars by water molecules and resulting in a most unusual crystalline and permanently porous structure.

Metal-organic frameworks (MOFs) have gained considerable attention as hybrid materials-in part because of a multitude of potential useful applications, ranging from gas separation to catalysis and light harvesting. Unfortunately, de novo synthesis of MOFs with desirable function-property combinations is not always reliable and may suffer from vagaries such as formation of undesirable topologies, low solubility of precursors, and loss of functionality of the sensitive network components. The recently discovered synthetic approach coined solvent-assisted linker exchange (SALE) constitutes a simple to implement strategy for circumventing these setbacks; its use has already led to the generation of a variety of MOF materials previously unobtainable by direct synthesis methods. This Review provides a perspective of the achievements in MOF research that have been made possible with SALE and examines the studies that have facilitated the understanding and broadened the scope of use of this invaluable synthetic tool.

We designed, synthesized, and characterized a new Zr-based metal-organic framework material, NU-1100, with a pore volume of 1.53 ccg(-1) and Brunauer-Emmett-Teller (BET) surface area of 4020 m(2) g(-1) ; to our knowledge, currently the highest published for Zr-based MOFs. CH4 /CO2 /H2 adsorption isotherms were obtained over a broad range of pressures and temperatures and are in excellent agreement with the computational predictions. The total hydrogen adsorption at 65 bar and 77 K is 0.092 g g(-1) , which corresponds to 43 g L(-1) . The volumetric and gravimetric methane-storage capacities at 65 bar and 298 K are approximately 180 vSTP /v and 0.27 g g(-1) , respectively.

Dichloroaluminum benzoate and its adducts with Lewis bases show a large structural variety from molecular complexes to ionic species as indicated by X-ray diffraction, spectroscopic studies, and quantum-chemical calculations.

We have authenticated the molecular and crystal structure of ZntBu2 and constructed the unprecedented 2D fabric structure using the tert-butylzinc molecules and 1,2-bis(4-pyridyl)ethane as building blocks. The X-ray crystal structure analysis revealed that the inorganic−organic polymeric chains were weaving to form the fabric structure by the concerted C−H···π interactions involving the pyridine rings. Subtle factors governing self-assembly processes leading to a fabric structure are discussed.