Search

Effective separation of hexane (C6) isomers is critical for a variety of industrial applications but conventional distillation methods are energy‐intensive. Adsorptive separations based on porous coordination polymers (PCPs) offer a promising alternative due to their exceptional porosity and tunable properties. However, there is still an urgent need to develop PCPs with high stability and separation performance. This study investigates how substituting a methyl (−CH3) group with a trifluoromethyl (−CF3) group can regulate pores and hydrophobicity in PCPs. This precise adjustment aims to enhance stability and improve the kinetic separation performance of hydrophobic C6 isomers by considering the size and hydrophobicity of the trifluoromethyl group. Two isostructural PCPs with pcu topology, PCP‐CH3 and PCP‐CF3, were synthesized to vary pore diameters and hydrophobicity based on the presence of −CH3 or −CF3 groups. PCP‐CF3 showed greater stability in water compared to PCP‐CH3. While PCP‐CH3 had high adsorption capacities, it lacked selectivity, whereas PCP‐CF3 demonstrated improved selectivity, particularly in excluding dibranched isomers. Dynamic column separation experiments revealed that PCP‐CF3 could selectively adsorb linear and monobranched isomers over dibranched isomers at room temperature. These findings highlight the potential of fluorine‐modified PCPs for efficient isomer separation and underscore the importance of stability improvement strategies. [ABSTRACT FROM AUTHOR]

AbstractThe removal of carbon dioxide (CO2) from acetylene (C2H2) represents a pivotal industrial process for the production of high-purity C2H2. Nevertheless, the separation of C2H2 and CO2 is challenging due to their highly similar molecular sizes and physical properties. In this work, we report a fine regulation of a sql layered coordination polymer (termed NTU-107) into a rare fsc open framework (termed NTU-108) with naphthalenedisulphonic acid pillar for selective C2H2 capture from CO2-contained mixtures. NTU-107 was prepared by the reaction of 4-(1H-imidazol-1-yl)benzoic acid (L1) ligand and Cu2+ ion, showing a layered framework with a pore size of 4.2 Å. After inserting 1,5-naphthalenedisulphonic acid between the layers, a new pillar-layered open framework (5.8 Å) with sulphonic acid functional sites was prepared. Single-component gas adsorption experiments and breakthrough experiments demonstrated that NTU-108 with accessible sulphonic acid sites exhibits a high C2H2 absorption capacity and dynamic C2H2/CO2 separation performance at room temperature. [ABSTRACT FROM AUTHOR]

Reticular materials are one of the more promising tools that humankind has developed to address the required energy transition. Despite their great potential showcased in the last decade, their use is so far mainly confined to the laboratory bench due to drawbacks derived from their powdery morphology. Unlike zeolites and activated carbons, the challenges in shaping and densification of reticular materials hamper their full implementation in the industry. Hence, strategies for shaping and integrating these materials need to be prioritized. Most of the existing strategies rely on applying mechanical pressure and adding chemical binders, but these approaches, although useful for shaping, diminish their final adsorption capacities and do not bring their theoretical, predicted performance. On the other hand, obtaining self‐shaped, dense bodies—so‐called monoliths—arises as a very promising and scalable alternative. Sol–gel monoliths are still scarce in the scientific literature despite their outstanding performance, particularly in terms of volumetric adsorption capacity. This review intends to help expand this scope by offering a rational guide on the self‐shaping of dense monoliths for reticular materials, as well as a complete revision of the state‐of‐the‐art in the field. [ABSTRACT FROM AUTHOR]

Designing efficient proton-conductive materials is crucial in fuel cells. Yet, it remains a substantial challenge because of the issues in proton mobility, proton-carrier amount, and orientation of proton host materials. Herein, we report an in-situ protonation strategy to produce a locally flexible porous coordination polymer (PCP) to enhance the proton-carrier loading and proton conductivity. The local dipole flipping of the ligand allows effective proton exchange with low activation energy, promoting interpore proton transport through the pore apertures and pore walls. The protonation induces substantial charges to the frameworks and enhances the interaction with proton carriers, thereby increasing the loading of the proton carriers. By this design strategy, the resulting PCP exhibits enhanced phosphoric acid loading and extraordinary proton conductivities under both aqueous and anhydrous conditions compared to its isoreticular analog that features rigidity without proton-exchange capability. Our work provides a new avenue for designing proton-conductive materials that combine structural dynamics with performance merits. [ABSTRACT FROM AUTHOR]

Cost‐effective and facile synthetic routes to organic ligands, along with porous materials that exhibit exceptional gas‐storage properties, promise significant industrial applications. Here, a two‐step synthesis of novel organophosphorus ligands without metal catalysts is reported. These ligands serve as versatile linkers for the construction of metal‐organic frameworks (MOFs) incorporating various metal ions, including zinc and copper. One of the zinc‐based MOFs demonstrates remarkable gas‐storage properties, with a hydrogen (H2) capacity exceeding 2.5 wt% at 77 K and 100 kPa as well as a carbon dioxide (CO2) capacity exceeding 20 wt% at 298 K and 100 kPa. Furthermore, this zinc‐based MOF can be synthesized through a solvothermal process on the gram scale that yields high‐quality single crystals. [ABSTRACT FROM AUTHOR]

Crystalline frameworks represent a cutting‐edge frontier in material science, and recently, there has been a surge of interest in energetic crystalline frameworks. However, the well‐established porosity often leads to diminished output energy, necessitating a novel approach for performance enhancement. Thiol‐yne coupling, a versatile metal‐free click reaction, has been underutilized in crystalline frameworks. As a proof of concept, we herein demonstrate the potential of this approach by introducing the energy‐rich, size‐matched, and reductive 1,2‐dicarbadodecaborane‐1‐thiol (CB−SH) into an acetylene‐functionalized framework, Zn(AIm)2, via thiol‐yne click reaction. This innovative decoration strategy resulted in a remarkable 46.6 % increase in energy density, a six‐fold reduction in ignition delay time (4 ms) with red fuming nitric acid as the oxidizer, and impressive enhancement of stability. Density functional theory calculations were employed to elucidate the mechanism by which CB−SH promotes hypergolic ignition. The thiol‐yne click modification strategy presented here permits engineering of crystalline frameworks for the design of advanced energetic materials. [ABSTRACT FROM AUTHOR]

Two porphyrin-based polymeric frameworks, SnP-BTC and SnP-BTB, as visible light photocatalysts for wastewater remediation were prepared by the solvothermal reaction of trans-dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(IV) (SnP) with 1,3,5-benzenetricarboxylic acid (H3BTC) and 1,3,5-tris(4-carboxyphenyl)benzene (H3BTB), respectively. The strong bond between the carboxylic acid group of H3BTC and H3BTB with the axial hydroxyl moiety of SnP leads to the formation of highly stable polymeric architectures. Incorporating the carboxylic acid group onto the surface of SnP changes the conformational frameworks as well as produces rigid structural transformation that includes permanent porosity, good thermodynamic stability, interesting morphology, and excellent photocatalytic degradation activity against AM dye and TC antibiotic under visible light irradiation. The photocatalytic degradation activities of AM dye were found to be 95% by SnP-BTB and 87% by SnP-BTC within 80 min. Within 60 min of visible light exposure, the photocatalytic degradation activities of TC antibiotic were found to be 70% by SnP-BTB and 60% by SnP-BTC. The enhanced catalytic photodegradation performances of SnP-BTB and SnP-BTC were attributed to the synergistic effect between SnP and carboxylic acid groups. The carboxylic acid connectors strongly resist the separation of SnP from the surface of SnP-BTB and SnP-BTC during the photodegradation experiments. Therefore, the high degradation rate and low catalyst loading make SnP-BTB or SnP-BTC more efficient than other reported catalysts. Thus, the present investigations on the porphyrin-based photocatalysts hold great promise in tackling the treatment of dyeing wastewater.

The improvement of sustainable chemical processes plays a pivotal role in safe environmental and societal development, for example, by reducing the use of hazardous substances, preventing chemical waste, and improving the efficiency of chemical reactions to obtain added-value compounds. In this context, the porous coordination polymer MOF-808 (MOF, metal–organic framework) was prepared by a straightforward method in water, at room temperature, and was unequivocally characterized by powder X-ray diffraction, vibrational spectroscopy, thermogravimetric analysis, and scanning electron microscopy. MOF-808 material was applied for the first time as catalysts in ring-opening aminolysis reactions of epoxides. It demonstrated high activity and selectivity for reactions of styrene oxide and cyclohexene oxide with aniline, using a very low amount of an eco-sustainable solvent (0.5 mL of EtOH), at 70 °C. Moreover, MOF-808 demonstrated high stability in the catalytic reaction conditions applied, and a notable reuse capacity of up to 20 consecutive reaction cycles, without significant variation in its catalytic performance. In fact, this Zr-based porous coordination polymer prepared by environment-friendly conditions proved to be a novel efficient heterogeneous catalyst, promoting the ring-opening reaction of epoxides under more sustainable conditions, and using a very low amount of catalyst. [ABSTRACT FROM AUTHOR]

A series of metal–organic frameworks (MOFs) based on zinc ions and two triptycene ligands of different size have been synthesized under solvothermal conditions. Structural analyses revealed that they are isostructural 3D‐network MOFs. The high porosity and thermal stability of these MOFs can be attributed to the highly rigid triptycene‐based ligands. Their BET specific surface areas depend on the size of the triptycene ligands. In contrast to these surface‐area data, the H2 and CO2 adsorption of these MOFs is larger for MOFs with small pores. Consequently, we introduced functional groups to the bridge‐head position of the triptycene ligands and investigated their effect on the gas‐sorption properties. The results unveiled the role of the functional groups in the specific CO2 binding via an induced interaction between adsorbates and the functional groups. Excellent H2 and CO2 properties in these MOFs were achieved in the absence of open metal sites. [ABSTRACT FROM AUTHOR]

We have developed highly porous Cu‐based metal–organic frameworks (MOFs) using carbazole‐type linkers. The novel topological structure of these MOFs was revealed by single‐crystal X‐ray diffraction analysis. Molecular adsorption/desorption experiments indicated that these MOFs are flexible and change their structure upon adsorption/desorption of organic solvents and gas molecules. These MOFs exhibit unprecedented properties that allow controlling their flexibility by adding a functional group onto the central benzene ring of the organic ligand. For example, the introduction of electron‐donating substituents increases the robustness of the resulting MOFs. These MOFs also exhibit flexibility‐dependent differences in gas‐adsorption and ‐separation performance. Thus, this study represents the first example of controlling the flexibility of MOFs with the same topological structure via the substituent effect of functional groups introduced into the organic ligand. [ABSTRACT FROM AUTHOR]

The nanoconfinement of proton carrier molecules may contribute to the lowing of their proton dissociation energy. However, the free proton transportation does not occur as easily as in liquid due to the restricted molecular motion from surface attraction. To resolve the puzzle, herein, imidazole is confined in the channels of porous coordination polymers with tunable geometries, and their electric/structural relaxations are quantified. Imidazole confined in a square‐shape channels exhibits dynamics heterogeneity of core‐shell‐cylinder model. The core and shell layer possess faster and slower structural dynamics, respectively, when compared to the bulk imidazole. The dimensions and geometry of the nanochannels play an important role in both the shielding of the blocking effect from attractive surfaces and the frustration filling of the internal proton carrier molecules, ultimately contributing to the fast dynamics and enhanced proton conductivity. [ABSTRACT FROM AUTHOR]

Single crystals of two spin-crossover (SCO) cyanometallic coordination polymers based on the pyridazino[4,5-d]pyridazine ligand (pp) of the composition [Fe(pp)M(CN)4]∙G (where M = Pd, Pt; G = guest molecules) were obtained by a slow diffusion technique. A single-crystal X-ray analysis showed that both compounds adopted the structure of porous 3D frameworks, consisting of heterometallic cyano-bridged layers and interlayer pillar pp ligands, with a total solvent accessible volume of ca. 160 Å3 per iron(II) ion (about 37% of the unit cell volume). These frameworks displayed hysteretic SCO behaviour with T1/2 of 150/190 K (heating/cooling) for Pd complex and 135/170 K (heating/cooling) for Pt complex, which was confirmed by variable-temperature SCXRD experiments. This research shows the perspective of using pp ligand for building porous MOFs with spin transitions. [ABSTRACT FROM AUTHOR]

Two porphyrin-based polymeric frameworks, SnP-BTC and SnP-BTB, as visible light photocatalysts for wastewater remediation were prepared by the solvothermal reaction of trans -dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(IV) (SnP) with 1,3,5-benzenetricarboxylic acid (H 3 BTC) and 1,3,5-tris(4-carboxyphenyl)benzene (H 3 BTB), respectively. The strong bond between the carboxylic acid group of H 3 BTC and H 3 BTB with the axial hydroxyl moiety of SnP leads to the formation of highly stable polymeric architectures. Incorporating the carboxylic acid group onto the surface of SnP changes the conformational frameworks as well as produces rigid structural transformation that includes permanent porosity, good thermodynamic stability, interesting morphology, and excellent photocatalytic degradation activity against AM dye and TC antibiotic under visible light irradiation. The photocatalytic degradation activities of AM dye were found to be 95% by SnP-BTB and 87% by SnP-BTC within 80 min. Within 60 min of visible light exposure, the photocatalytic degradation activities of TC antibiotic were found to be 70% by SnP-BTB and 60% by SnP-BTC. The enhanced catalytic photodegradation performances of SnP-BTB and SnP-BTC were attributed to the synergistic effect between SnP and carboxylic acid groups. The carboxylic acid connectors strongly resist the separation of SnP from the surface of SnP-BTB and SnP-BTC during the photodegradation experiments. Therefore, the high degradation rate and low catalyst loading make SnP-BTB or SnP-BTC more efficient than other reported catalysts. Thus, the present investigations on the porphyrin-based photocatalysts hold great promise in tackling the treatment of dyeing wastewater.

Single‐cell multiplexing is key to exploration of the heterogeneous cell populations in biological systems. Although the state‐of‐the‐art mass cytometry (CyTOF) possesses high resolution and multiple dimensions, the lack of suitable marker materials prohibits fully exploiting the available CyTOF detection channels. Here we report a new design strategy for CyTOF markers using functionalized mesoporous porphyrinic frameworks (MPFs) as scaffolds for chelating metals that have been unachievable by conventional approaches. We developed surface modification for stably dispersing the MPF nanoparticles (<40 nm) during the metalation and antibody conjugation processes. Our markers exhibit higher sensitivity and comparable specificity compared with a polymer‐based commercial benchmark. Compatibility with commercial markers during co‐staining was also confirmed. Furthermore, our markers show promising performance for immunophenotyping and potential implementation in CyTOF systems. [ABSTRACT FROM AUTHOR]

International guidelines have progressively addressed global warming which is caused by the greenhouse effect. The greenhouse effect originates from the atmosphere's gases which trap sunlight which, as a consequence, causes an increase in global surface temperature. Carbon dioxide is one of these greenhouse gases and is mainly produced by anthropogenic emissions. The urgency of removing atmospheric carbon dioxide from the atmosphere to reduce the greenhouse effect has initiated the development of methods to covert carbon dioxide into valuable products. One approach that was developed is the photocatalytic transformation of CO2. Photocatalysis addresses environmental issues by transferring CO2 into value added chemicals by mimicking the natural photosynthesis process. During this process, the photocatalytic system is excited by light energy. CO2 is adsorbed at the catalytic metal centers where it is subsequently reduced. To overcome several obstacles for achieving an efficient photocatalytic reduction process, the use of metal-containing polymers as photocatalysts for carbon dioxide reduction is highlighted in this review. The attention of this manuscript is directed towards recent advances in material design and mechanistic details of the process using different polymeric materials and photocatalysts. [ABSTRACT FROM AUTHOR]

A thiourea hexamethylene diisocyanate covalent organic framework (TH COF) was synthesized by adjusting the surface charge and surface area. The surface charge value of TH COF, −3.8 ± 0.5 mV, can be changed to −29.1 ± 0.4 mV by treatment with NaOH (dp-TH) and 17.1 ± 1.0 mV by treatment with HCl (p-TH). Additionally, the surface area of TH COF was 39.3 m2/g, whereas the surface area of dp-TH COF and p-TH COF structures were measured as 41.4 m2/g and 42.5 m2/g, respectively. However, the COF structure had a better adsorption capability with acid and base treatments, e.g., dp-TH COF absorbed 5.5 ± 0.3 mg/g methylene blue (MB) dye, and p-TH COF absorbed 25.9 ± 1.4 mg/g methyl orange (MO) dye from 100 mL 25 ppm aqueous dye solutions, thereby increasing the MB and MO absorption amounts of the TH COF structure. Furthermore, by calculating the distribution, selectivity, and relative selectivity coefficients, the absorption capacity order was determined as dp-TH > TH > p-TH COFs for the MB dye, whereas it was p-TH > TH > dp-TH COFs for the MO dye. Finally, the reusability of dp-TH COF for MB absorption and p-TH COF for MO absorption were investigated. After five repeated uses, dp-TH COF retained 64.6 ± 3.7% of its absorption ability, whereas p-TH COF preserved 79.7 ± 3.2% of its absorption ability relative to the initial absorption amount. [ABSTRACT FROM AUTHOR]

This work demonstrates the fabrication of a nanoporous iron carbide-iron oxide/reduced graphene oxide (IC-IO/ rGO) hybrid via a controlled one-step thermal treatment of Prussian blue (PB)/GO hybrid at 450 °C under N2 flow. The PB/GO hybrid is initially prepared through the in-situ deposition of PB nanoparticles on the GO sheets through electrostatic interactions. The morphological analysis of the hybrid reveals the uniform coverage of the rGO sheets by IC-IO nanoparticles and the even distribution of carbon (C), oxygen (O), and iron (Fe) on the rGO nanosheets. As a result of the hybrid composition and controlled morphology, the surface area of the obtained IC-IO/rGO hybrid (~40 m2/g) is significantly enhanced compared to those of the calcined GO sheets and PB nanoparticles (without GO).

To develop an efficient CO2 reduction catalyst, hybridizing a molecular catalyst and a porous coordination polymer (PCP) is a promising strategy because it can combine both advantages of the precise reactivity control of the former and the CO2 adsorption property of the latter. Although several PCP hybrid catalysts have been reported to date, the CO2 sorption behavior and the CO2 reduction reactivity have been investigated separately, and the CO2 enrichment during the catalysis is still unclear. We report CO2 photoreduction under different temperatures and pressures using a PCP‐RuII complex hybrid catalyst. The product selectivity (CO or HCOOH) varied depending on the reaction conditions. The altered selectivity could be interpreted in terms of the CO2 capture in the micropores of a PCP. [ABSTRACT FROM AUTHOR]

Single crystals of two spin-crossover (SCO) cyanometallic coordination polymers based on the pyridazino[4,5-d]pyridazine ligand (pp) of the composition [Fe(pp)M(CN)4]∙G (where M = Pd, Pt; G = guest molecules) were obtained by a slow diffusion technique. A single-crystal X-ray analysis showed that both compounds adopted the structure of porous 3D frameworks, consisting of heterometallic cyano-bridged layers and interlayer pillar pp ligands, with a total solvent accessible volume of ca. 160 Å3 per iron(II) ion (about 37% of the unit cell volume). These frameworks displayed hysteretic SCO behaviour with T1/2 of 150/190 K (heating/cooling) for Pd complex and 135/170 K (heating/cooling) for Pt complex, which was confirmed by variable-temperature SCXRD experiments. This research shows the perspective of using pp ligand for building porous MOFs with spin transitions.

Main observation and conclusion: Magnifying the controllable directional motions of molecular machines to the macroscopic levels is a significant topic for chemists. Flexible metal–organic frameworks with long‐range order and responsive structural transformation under external stimuli may be an appropriate platform for achieving the target. By taking advantage of the single‐crystal to single‐crystal manner of soft porous crystals, we utilize single‐crystal X‐ray diffraction to directly observe the dynamic structural inversion of a new three‐fold interpenetrated pillared‐layer metal‐organic framework [Co(edba)(bpy)] (MCF‐83, H2edba = 4,4'‐(ethyne‐1,2‐diyl)dibenzoic acid, bpy = 4,4'‐bipyridine). More interestingly, the dynamic inversions of the pillars and layers are selectively guest‐controllable and independent, allowing precise control of the directional shape changes, which is the key of constructing intelligent materials to accomplish a complex task. The mechanism is further studied by combining the X‐ray diffraction analyses, sorption measurements and molecular simulations. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Magnifying the controllable directional motions of molecular machines to the macroscopic levels is a significant topic for chemists. Flexible metal–organic frameworks with long‐range order and responsive structural transformation under external stimuli may be an appropriate platform for achieving the target. By taking advantage of the single‐crystal to single‐crystal manner of soft porous crystals, we utilize single‐crystal X‐ray diffraction to directly observe the dynamic structural inversion of a new three‐fold interpenetrated pillared‐layer metal‐organic framework [Co(edba)(bpy)] (MCF‐83, H2edba = 4,4'‐(ethyne‐1,2‐diyl)dibenzoic acid, bpy = 4,4'‐bipyridine). More interestingly, the dynamic inversions of the pillars and layers are selectively guest‐controllable and independent, allowing precise control of the directional shape changes, which is the key of constructing intelligent materials to accomplish a complex task. The mechanism is further studied by combining the X‐ray diffraction analyses, sorption measurements and molecular simulations. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs), crystalline materials with high internal surface area and pore volume, have demonstrated great potential for many applications. In the past decade, as large number of MOFs have come into existence, there has been an effort to model them using computers. High-throughput screening techniques in tandem with molecular simulations or ab-initio calculations are being used to calculate their properties. However, the number of MOFs that can be hypothetically created are in the millions, and though computer simulations have shown remarkable accuracy, we cannot deploy them for all structures due to their high-computational cost. In this regard, machine learning (ML)-based algorithms have proven to be effective in predicting material properties and reducing the need for expensive calculations. Adopting this methodology can save time and allow researchers to explore materials in unchartered chemical space, thus ushering an era of high-throughput in-silico material design using ML. In this work, we present what is ML, its associated workflow, selecting descriptors, and how it can help build reliable models for discovering MOFs. We present some popular and novel ones. Thereafter, we review some of the recent studies with respect to ML-based implementation for MOF discovery emphasizing descriptors selected and the workflow adopted. [ABSTRACT FROM AUTHOR]

Two carboxyl‐functional Mn (III)–porphyrins reacted with two metal nitrates (Cr (NO3)3·9H2O and Al (NO3)3·9H2O) via solvothermal method, respectively, to produce four metalloporphyrin‐based metal organic gels (MOGs). To remove unreacted metal salts and DMF, the gels were dealt with Soxhlet extraction and supercritical CO2. Finally, four desired porous coordination polymers (PCPs) were prepared. The newly synthesized PCPs were characterized by FT‐IR, UV–vis, SEM, and TEM. The contrast experiments show these PCPs possess good catalytic activities for the cycloaddition reactions of epoxide and CO2 under mild and solvent‐free conditions using tetrabutylammonium bromide (TBAB) as co‐catalyst. [ABSTRACT FROM AUTHOR]

Controlling gas sorption by simple pore modification is important in molecular recognition and industrial separation processes. In particular, it is challenging to realize the inverse selectivity, which reduces the adsorption of a high‐affinity gas and increases the adsorption of a low‐affinity gas. Herein, an "opposite action" strategy is demonstrated for boosting CO2/C2H2 selectivity in porous coordination polymers (PCPs). A precise steric design of channel pores using an amino group as an additional interacting site enabled the synergetic increase in CO2 adsorption while suppressing the C2H2 adsorption. Based on this strategy, two new ultramicroporous PCP physisorbents that are isostructural were synthesised. They exhibited the highest CO2 uptake and CO2/C2H2 volume uptake ratio at 298 K. Origin of this specific selectivity was verified by detailed density functional theory calculations. The breakthrough separation performances with remarkable stability and recyclability of both the PCPs render them relevant materials for C2H2 purification from CO2/C2H2 mixtures. [ABSTRACT FROM AUTHOR]

A thiourea hexamethylene diisocyanate covalent organic framework (TH COF) was synthesized by adjusting the surface charge and surface area. The surface charge value of TH COF, −3.8 ± 0.5 mV, can be changed to −29.1 ± 0.4 mV by treatment with NaOH (dp-TH) and 17.1 ± 1.0 mV by treatment with HCl (p-TH). Additionally, the surface area of TH COF was 39.3 m2/g, whereas the surface area of dp-TH COF and p-TH COF structures were measured as 41.4 m2/g and 42.5 m2/g, respectively. However, the COF structure had a better adsorption capability with acid and base treatments, e.g., dp-TH COF absorbed 5.5 ± 0.3 mg/g methylene blue (MB) dye, and p-TH COF absorbed 25.9 ± 1.4 mg/g methyl orange (MO) dye from 100 mL 25 ppm aqueous dye solutions, thereby increasing the MB and MO absorption amounts of the TH COF structure. Furthermore, by calculating the distribution, selectivity, and relative selectivity coefficients, the absorption capacity order was determined as dp-TH > TH > p-TH COFs for the MB dye, whereas it was p-TH > TH > dp-TH COFs for the MO dye. Finally, the reusability of dp-TH COF for MB absorption and p-TH COF for MO absorption were investigated. After five repeated uses, dp-TH COF retained 64.6 ± 3.7% of its absorption ability, whereas p-TH COF preserved 79.7 ± 3.2% of its absorption ability relative to the initial absorption amount.

Incorporating local mobility into a flexible framework promises to create cooperative properties unattainable in a conventional soft porous crystal. In this study, we propose a design strategy that integrates substituent moieties and a flexible porous crystal framework via intra‐framework π–π interactions. This integration not only facilitates framework structural transitions but also gives the porous coordination polymers (PCPs) different guest‐free structures that depend on the activation conditions. The incorporated flexibility gives the material the ability to discriminate C6 alkane isomers based on different gate‐opening behaviors. Thus, the PCP has potential applications in C6 isomer separation, a critical step in the petroleum refining process to produce gasoline with high octane rating. This strategy, based on ligand designability, offers a new approach to flexible PCP structural and functional design. [ABSTRACT FROM AUTHOR]

3-Ethyl-5-trifluoromethyl-1,2,4-triazole is synthesized by a one-pot reaction. Using this asymmetric triazole ligand bearing one trifluoromethyl and one ethyl as side groups, we construct two new porous coordination polymers, MAF-9 and MAF-2F, being isostructural with the classic hydrophobic and flexible materials, FMOF-1 and MAF-2, based on symmetric triazole ligands bearing two trifluoromethyl groups or two ethyl groups, respectively. MAF-9 and MAF-2F can adsorb large amounts of organic solvents but completely exclude water, showing superhydrophobicity with water contact angles of 152o in between those of FMOF-1 and MAF-2. MAF-9 exhibits very large N2-induced breathing and colossal positive and negative thermal expansions like FMOF-1, but the lower molecular weight and smaller volume of MAF-9 give 16% and 4% higher gravimetric and volumetric N2 uptakes, respectively. In contrast, MAF-2F is quite rigid and does not show the inversed temperature-dependent N2 adsorption and large guest-induced expansion like MAF-2. Further, despite the higher molecular weight and larger volume, MAF-2F possesses 6% and 25% higher gravimetric and volumetric CO2 uptakes, respectively. These results can be explained by the different pore sizes and side group arrangements in the two classic framework prototypes, which demonstrate the delicate roles of ligand side groups in controlling porosity, surface characteristic and flexibility. [ABSTRACT FROM AUTHOR]

In this review, we account the recent advancements on cyclotriphosphazene (N3P3Cl6) based multi‐site coordination ligands for the synthesis of multi‐metallic architectures. In case of N3P3Cl6, Phosphorous centres with two chlorides use to be bonded with nitrogen [−P(Cl2)=N−]3 at alternative positions in six membered ring to provide a robust planar structure to anchor the ligand arms with wide flexibility. Cyclic P−N robust motif is renowned as the potential support for the design of multi‐site ligands originating from phosphorus centres by viable substitution of variable number of ligand units (1 to 6) consist of one or more coordination site(s) via geminal and/or non‐geminal modes. Despite these phosphorus centres are promising to support in ligand structure, occasionally involve in coordination with transition metals as well. Three of alternative nitrogen atoms in this heterocyclic core are supposed to function as Lewis base centres while the electron releasing substituents occurred to tether on phosphorus centres, also when the resultant ring size favours adequate interaction towards the transition metal ions with respect to skeletal flexibility. The ligand modes vary with respect to numbers and orientation of coordination sites, which is imperative to enrich the ligation ability. Moreover, several examples of cyclotriphosphazene core ligands consist of the spacer oxygen atom while tethering with exocyclic ligand units to incorporate more flexibility. In accordance with coordination sites on ligand framework and choice of metal, the skeletal ring nitrogen atom(s) of the cyclotriphosphazene can be involved in coordination with metal ions. Indeed, the coordination of ligands is reported to coordinate with main group, transition and lanthanide metal ions to form variety of metal clusters and porous coordination polymers. Subsequently, the geometry of homo or heterometallic complexes with respect to versatile coordination modes of metallic complexes tends to afford inherent chemical properties for specific application. In terms of exocyclic ligands, the heterocyclic units such as pyridyloxy‐, pyrazolyl‐, pyridylalkylamino‐, bipyridyl‐, 1,10‐phenanthroline, porphyrinato, hydrazide, hydrazone, Schiff's base and spirocyclic amine units attached to cyclotriphosphazene were exploited to form series of metal complexes. Similarly, the variety of metal clusters, polymeric network (1D to 3D) and porous coordination polymers have been reported on basis of cyclic core molecule substituted with ligand units, pyridyloxy‐, multi‐carboxylic, aromatic amines substituted pyridyloxy‐ and imidazole moiety involved to form variety of products. [ABSTRACT FROM AUTHOR]

We report the two-step synthesis of a novel chiral rod-based porous coordination polymer (PCP). The chemical approach consists of the use of a previously prepared bis(ethylenediamine) copper monomer [Cu(en)]2(NO3)2 [where en = ethylenediamine] reacting with the cytidine 5′-monophosphate (CMP) nucleotide. The bis(ethylenediamine) copper compound—stabilized by axial coordination of nitrate counter-anions—reacts in the presence of sodium salt of CMP to yield right-handed copper(II) chains of P helicity with formula [Cu2(en)2(CMP)2]·5H2O (1). The axial coordination of the CMP2- ligands through the N3 and O2 sites (free nitrogen and carbonyl groups) of the cytosine nucleobase and oxygen atoms of phosphate moieties, ensure stabilization of the neutral chiral polymer. The supramolecular organization involves strong hydrogen bonding interactions to build supramolecular chains of the same helicity. The resulting PCP constitutes one of the few examples of CMP compounds exhibiting coordination involving both nucleobase and phosphate moieties, where a highly stable metal complex is used as precursor for the rational construction of rod-based hydrogen metal-organic frameworks (HMOFs). Furthermore, it shows the intrinsic capability of biomolecules to act as chiral transfer systems. [ABSTRACT FROM AUTHOR]

This work demonstrates the fabrication of a nanoporous iron carbide-iron oxide/reduced graphene oxide (IC-IO/ rGO) hybrid via a controlled one-step thermal treatment of Prussian blue (PB)/GO hybrid at 450 °C under N2 flow. The PB/GO hybrid is initially prepared through the in-situ deposition of PB nanoparticles on the GO sheets through electrostatic interactions. The morphological analysis of the hybrid reveals the uniform coverage of the rGO sheets by IC-IO nanoparticles and the even distribution of carbon (C), oxygen (O), and iron (Fe) on the rGO nanosheets. As a result of the hybrid composition and controlled morphology, the surface area of the obtained IC-IO/rGO hybrid (~40 m²/g) is significantly enhanced compared to those of the calcined GO sheets and PB nanoparticles (without GO). [ABSTRACT FROM AUTHOR]

Proton conductivity has been traditionally investigated with various materials such as organic polymers, metal oxides, and other inorganic and organic compounds because of their potential application in the electrochemical devices. In particular, during the last decade, crystalline porous coordination polymers (PCPs) or metal‐organic frameworks (MOFs) have received considerable attention in recent years, as solid‐state proton conductors (SSPCs). To date, proton‐conductive MOFs have achieved high performance in proton conductivity (>10−2 S cm−1) with rational design strategies. In addition, there are dedicated efforts to define the conduction pathway and mechanism using various experimental tools. In this review, we focus on the characterization of proton conductivity and molecular dynamics in hydrated MOFs, with selected examples to provide an understanding of the overall conduction mechanism. [ABSTRACT FROM AUTHOR]

The possibility of the chromatographic separation of isomeric nitroanilines and fluorine-substituted analogues using porous coordination polymers [Al(OH)(Fum)]n (I) (Fum2– is trans-1,2-ethylenedicarboxylic acid anion), [Al(OH)(Bdc)]n (II) (Bdc2– is 1,4-benzenedicarboxylic acid anion), [Cu3(Btc)2(H2O)3] (III) (Btc3– is 1,3,5-benzenetricarboxylic acid anion), and [Cr3(O)(OH)(H2O)2(Bdc)3] (IV) as stationary phases in a mixture of nonpolar solvents is studied. The separation of the amines is achieved only in the case of [Al(OH)(Fum)]n. Possible relationships of the separation factors of the amines to the sizes of the molecules, polarity, and lipophilicity are examined. Among the factors considered, only the difference between the values of lipophilicity exerts a noticeable effect on the efficiency. [ABSTRACT FROM AUTHOR]

A study of methane monooxygenase (MMO) mechanisms in enzymology and the problem of selective methane oxidation in chemistry are two parallel related fundamental directions that attract the attention of many scientists all over the world. For a long time, selective methane oxidation is considered as the strongest challenge in catalysis from the standpoint of practical applications. In spite of great efforts, no process acceptable for use in industry has yet been found for the direct conversion of methane to methanol and this problem still remains highly relevant. There are high expectations connected with MMOs, which are capable of transforming methane into methanol with a selectivity of up to 100% under natural environmental conditions. This review discusses the results of long and dramatic studies that have made it possible to elucidate structures of active sites and puzzling mechanisms of the two most studied MMOs: iron-containing soluble methane monooxygenase (sMMO) and copper-containing membrane-bound particulate methane monooxygenase (pMMO). Main attention is paid to various bioinspired models of these MMOs, both homogeneous and heterogeneous ones. The recent improvement of heterogeneous chemical analogues of MMOs, which effectively catalyze the direct selective oxidation of methane to methanol by hydrogen peroxide or O2, undoubtedly opens up new horizons for the chemical industry and has been actively discussed in recent years with regard to adaptation to modern technological requirements. [ABSTRACT FROM AUTHOR]

A composition was proposed based on microporous coordination polymers curable upon evaporation of the liquid phase or upon component polymerization induced by UV irradiation, which allows fabrication of items of arbitrary configuration. The obtained 3D objects were shown to be, in principle, applicable as stationary phases for the separation of amine-based dyes by liquid chromatography. [ABSTRACT FROM AUTHOR]

Porous coordination polymers or metal–organic frameworks with reversible phase‐transition behavior possess some attractive properties, and can respond to external stimuli, including physical and chemical stimuli, in a dynamic fashion. Their phase transitions can be triggered by adsorption/desorption of guest molecules, temperature changes, high pressure, light irradiation, and electric fields; these mainly include two types of transitions: crystal–amorphous and crystal–crystal transitions. These types of porous coordination polymers have received much attention because of their interesting properties and potential applications. Herein, reversible phase transition porous coordination polymers are summarized and classified based on different stimuli sources. Corresponding typical examples are then introduced. Finally, examples of their applications in gas separation, chemical sensors, guest molecule encapsulation, and energy storage are also presented. [ABSTRACT FROM AUTHOR]

• Bifunctional SnCes were synthesized utilizing the discrepancy of the metal ions. • Properties of SnCes related to the interfacial coordination of the metal ions. • Sn 13.2 Ce shows high activity and stability for conversion of glucose into HMF. A novel porous coordination polymer (namely SnCe) has been synthesized by simultaneous coordination of Tin (Sn (IV)) and cerium (Ce (III/IV)) with the two ligands 5-sulfoisophthalic acid (SPA) and 1,3,5-benzenetricarboxylic acid (BTC). The morphology and surface area of SnCe can be controlled by the cerium-involved interfacial coordination, by taking advantage of the discrepancy of coordination ability between the two metal ions. The shape and size of the SnCes has a close relationship with the molar ratio of Sn to Ce. The mechanism of the formation of SnCe was investigated by electron microscopy measurement (scanning electron microscope) and XRD patterns. The catalysis capability was also controlled, with Sn (IV) and Ce (III/IV) as the Lewis acid sites and the sulfonate groups of SPA as the Brønsted acid sites. The Lewis acid sites can catalyze isomerization of glucose into fructose, and the Brønsted acid sites can catalyze the dehydration of fructose to 5-hydroxymethylfurfural (HMF) with a high efficiency. Thus, SnCe combines the bifunctional catalysis capability for producing HMF (an important platform chemical) from glucose. This work found that the morphology of catalyst has an effect on the catalyst capability. At the similar reaction conditions, the catalyst exhibits higher conversion and selectivity than those reported. [ABSTRACT FROM AUTHOR]

The stability of porous coordination polymers during an electrochemical reaction could be improved by introducing supporter materials. An I3O0-type inorganic hybrid electrocatalyst, cobalt cinnamate, supported on reduced graphene oxide (rGO) was successfully prepared for an oxygen evolution reaction. The electrocatalytic activity and stability of cobalt cinnamate(catalyst)/rGO composite were significantly improved due to the strong interaction between catalyst and supporter, which led to enhanced anchoring stability and electrical conductivity. The catalyst/rGO composite shows ~30 mV reduction in overpotential and improvement in durability from ≥35% to ≥70% after a reaction time of 12 h, compared to the catalyst alone.

Single‐ligand‐based electronically conductive porous coordination polymers/metal–organic frameworks (EC‐PCPs/MOFs) fail to meet the requirements of numerous electronic applications owing to their limited tunability in terms of both conductivity and topology. In this study, a new 2D π‐conjugated EC‐MOF containing copper units with mixed trigonal ligands was developed: Cu3(HHTP)(THQ) (HHTP=2,3,6,7,10,11‐hexahydrotriphenylene, THQ=tetrahydroxy‐1,4‐quinone). The modulated conductivity (σ≈2.53×10−5 S cm−1 with an activation energy of 0.30 eV) and high porosity (ca. 441.2 m2 g−1) of the Cu3(HHTP)(THQ) semiconductive nanowires provided an appropriate resistance baseline and highly accessible areas for the development of an excellent chemiresistive gas sensor. [ABSTRACT FROM AUTHOR]

Structures of three acylhydrazidate-based porous coordination polymers were reported, reversible I 2 adsorption properties were investigated, and factors of influencing adsorption property were discussed. By employing the hydrothermal in situ acylation of organic acids with N 2 H 4 , three porous acylhydrazidate-based Zn2+/Cd2+ coordination polymers as [M(L1)(H 2 O)]·1.5H 2 O (H 2 L1 = benzimidazole-5,6-dihydrazide; M2+ = Zn2+ 1 , Cd2+ 2) and [Zn(HL2)(H 2 O)]·3H 2 O (H 3 L2 = 4,5-(di-(3′,4′-phthalhydrazide))) 3 were obtained. X-ray single-crystal diffraction analysis reveals that the frameworks of 1 – 3 can all be simplified into a (3 metal node ,3 ligand node)-connected net. However, since the ligands are different, they show the distinct structures: a C-tube-like structure for the isostructural 1 and 2 ; a 103 topology for 3. The cif-checking reports indicate that the solvent accessible voids in the structures of 1 – 3 are 1055 Å3, 1282.4 Å3, and 978 Å3, respectively. It is noteworthy that 3 is the first example of triacylhydrazidate-based coordination polymer. The investigation of the I 2 -adsorption property for two Zn2+ compounds suggests that both can adsorb reversibly the I 2 molecule. The adsorption amount for 3 (100 mg adsorbing 22.0 mg I 2) is a bit higher than that for 1 (100 mg accommodating 15.6 mg I 2). However, the adsorption speed for 3 is much faster than that for 1. About 5 s, the I 2 adsorption for 3 is close to saturation, while for 1 , it is about 20 days. This might be related to the number and the distribution for the uncoordinated N/O atoms on the side walls of the channels. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have evolved as an exciting class of materials in the domain of porous materials. The unique features of these materials arise from the combined properties of metal ions/clusters and organic struts which form the building blocks of these fascinating architectures. Among other multifarious applications, MOFs have shown tremendous applications as sensory materials for a wide variety of species. The signal transduction induced mechanism in these confined nanospaces generate optical output in response to a particular analyte which can be detected by wide variety of detection techniques. Fluorometric methods of sensing is one of widely studied method over past few decades. MOF‐based fluorometric detection is a key research theme developed over the past few years. In this review, we give a brief overview of the recent developments of MOFs as "turn‐on" sensors for a wide range of analytes (viz. cations, anions, volatile organic compounds (VOCs), etc.). [ABSTRACT FROM AUTHOR]

The metal-organic frameworks MIL-101 and sulfo-MIL-101 were used to modify graphite paste electrodes (GPEs) to obtain sensors for determination of dopamine (DA). Taking advantage of the catalytic activity of metal-organic frameworks (MOFs) and of the electrical conductivity of graphite, the modified GPEs show enhanced voltammetric responses, and the GPE modified with the sulfo-MOF displays superior sensitivity when operated at a working potential of −0.4 to 0.8 V (vs. Ag/AgCl). The sensor works in the 0.07 to100 μM DA concentration range and has a 43 nM detection limit. It is concluded that the sulfo group provides open sites for efficient electrostatic and hydrogen bonding interactions, which facilitates electron transfer. [ABSTRACT FROM AUTHOR]

Porous coordination polymer (PCP) with 2,7-bis(4-pyridyl)-[1]benzothieno[3,2-b][1]benzothiophene (BTBT-4py) ligands was synthesized. The PCP provides both pores and infinite π-stacked columns via the assemblies of linear coordination polymers. The overlap integrals between highest occupied molecular orbitals (HOMOs) of adjacent ligands largely depend on the conformation of BTBT cores. The PCP also showed drastic structural change induced by desolvation. This approach to introduce porosity in organic semiconductor crystal can lead to the development of molecular-based devices, such as porous field-effect transistor. [ABSTRACT FROM AUTHOR]

The four Prussian blue analogs (PBAs) under study in this contribution, T2[M(CN)6]·xH2O, have an open framework structure with 50 % of vacancies for the hexacyanometallate building block. In this series, the metal T is always found at the surface of the formed system of cavities and has a partially naked coordination environment. In the as‐synthesised materials, such available coordination sites are occupied by water molecules, which, in turn, stabilize additional water molecules inside the cavity through hydrogen bonding interactions. Herein, we report the synthesis, crystal structure, and related properties for the new title members of this family of coordination polymers, particularly for T = Ni, Cu and M = Ru, Os. To improve the material's crystallinity, the powders formed from the precipitation reaction were submitted to solvothermal recrystallization. Their crystal structure was solved and refined from the corresponding X‐ray diffraction (XRD) patterns. Unlike their FeII analogs, which crystallize in a Pm3m cubic structure, two types of cubic structures (depending on the external metal) were obtained: Fm3m for Ni2[M(CN)6]·xH2O and Pm3m for Cu2[M(CN)6]·xH2O. Such structural differences are properly supported by a detailed analysis of their IR and UV/Vis spectra. The stability of their porous network after water removal was evaluated by combining XRD, H2 adsorption isotherms, and thermogravimetric curves. Hydrogen adsorption was also used to explore the adsorption potential at the cavity surface. Except Cu2[Ru(CN)6]·xH2O, the other three materials appear to be stable after water removal under soft heating, which was ascribed to the role of the inner metal (RuII and OsII) on the framework robustness. These two metals have extended t2g orbitals, which favor the occurrence of a strong coupling between the inner and outer metals in the –T–N≡C‐M–C≡N‐T– chain. Apparently, such overlapping for charge density contributes to the material's stability. [ABSTRACT FROM AUTHOR]

Absorbents with high breakthrough efficiency and weak host–guest interaction are considered to be promising candidates for an energy‐saving process in feasible pressure/volume swing adsorption (PSA/VSA). Herein, two groups of finely designed Fe‐ and Co‐based porous coordination polymers (PCPs) are proposed and validated; these possess hourglass‐shaped nanochannels, through the cooperation of T‐shaped ligands with shifted methyl groups. Featuring optimal nanochannels, high static adsorption, and relatively lower binding energy, one of these polymers, named NTU‐30, enables significant C2H6/CH4 and C2H4/CH4 breakthrough efficiency, with approximately 1.0 or 0.6 g CH4 (100 %) harvested from the corresponding mixtures using 1 g of sample at ambient temperature. Furthermore, the positive effect of aromatic sites within NTU‐30 is detected and investigated through an in situ IR study. [ABSTRACT FROM AUTHOR]

In this study, two novel crystal materials pcp1 and pcp1‐L have been synthesized successfully. The different conformations of the two crystals are mainly attributed to the introduction of the Schiff‐base ligand L (L=(E)‐4‐methyl‐N‐((6‐methoxypyridin‐2‐yl)methylene)aniline). Subsequently, pcp1 and pcp1‐L composites have been firstly produced by a vacuum filtration method on various substrates (i.e. melamine foam, plastic mesh, carbon fiber cloth and glass cloth). The obtained robust composites show excellent performance in removing PMs owing to high ζ potential, microporous structure, large conjugation system and electron cloud‐exposed metal center (DFT calculations) of pcp1 and pcp1‐L. Particularly, pcp1‐L@glass cloth with low pressure drop exhibits high thermal stability and high long‐term reproducibility. Additionally, the high removal efficiency of pcp1‐L@glass cloth towards particulate matters could also be maintained, even achieving >99.9 % in the car exhaust gas field test. [ABSTRACT FROM AUTHOR]

Crystalline particles of a microporous, robust, and chiral metal–organic framework (MOF) were synthesized and their enantiomer excess (ee) was visualized for each microparticle by CD imaging. Labtb, a thermally and chemically robust MOF, was employed in this study because it shows a chiral space group. Although Labtb has been obtained as a racemic conglomerate, enantioselective synthesis of Labtb was achieved via a chiral precursor complex consisting of lanthanum and homochiral phenylalanine. Methyl orange (MO) was introduced into the micropores of chiral Labtb, which showed a strong induced CD signal for the absorption band of MO chromophores. High ee of the chiral Labtb was revealed by microscopic CD observation at the particle‐level. This result provides a facile way to obtain a robust MOF that has chiral nanospace. [ABSTRACT FROM AUTHOR]

Optimal control of gas adsorption properties in metal–organic frameworks (MOFs) or porous coordination polymers (PCPs) remains a great challenge in the field of materials science. An efficient strategy to capture electron‐acceptor‐type gas molecules such as nitrogen monooxide (NO) is to use host–guest interactions by utilizing electron‐donor‐type MOFs/PCPs as host frameworks. Herein, we focus on a highly electron‐donating chain compound by using the paddlewheel‐type [Ru2II,II] complex [Ru2(2,4,5‐Me3PhCO2)4] (2,4,5‐Me3PhCO2−=2,4,5‐trimethylbenzoate) with the phenazine (phz) linker: [Ru2(2,4,5‐Me3PhCO2)4(phz)] (1). Compound 1 exhibited a specific gated adsorption for NO under gas pressures greater than 60 kPa at 121 K, which finally resulted in approximately seven molar equivalents being taken up at 100 kPa followed by four molar equivalents remaining under vacuum at 121 K; its Rh isomorph (2) with weaker donation ability was inactive for NO. When the sample of 1⊃4 NO was heated to room temperature, the compound underwent a crystal‐to‐crystal phase transition to give [Ru2(2,4,5‐Me3PhCO2)4(NO)2](phz) (1‐NO), involving a post‐synthetic nitrosylation on the [Ru2] unit, accompanied by an eventful site‐exchange with phz. This drastic event, which is dependent on the NO pressure, temperature, and time, was coherently monitored by using several different in situ techniques, revealing that the stabilization of NO molecules in nanosized pores dynamically and stepwisely occurred with the support of strong electronic/magnetic host–guest interactions. In situ techniques: Selective NO capture in a Ru dimer chain porous compound through strong host–guest magnetic/electronic interactions was evaluated multilaterally by using in situ techniques of powder magnetic and permittivity measurements, IR spectroscopy, and X‐ray diffraction. A dynamic change with respect to the NO trapping in pores can be followed, which undergoes a crystal‐to‐crystal transformation from a gate‐opened NO adsorbed form to an NO‐adducted form. [ABSTRACT FROM AUTHOR]