Search

Long persistent luminescence (LPL) materials have been fascinating from ancient times till today, whereas the generation and modulation of LPL are still uncontrollable in most cases. In this paper,...

The indoor air quality is of prime importance for human daily life and health, for which the adsorbents like zeolites and silica-gels are widely used for air dehumidification and harmful gases capture. Herein, we develop a pore-nanospace post-engineering strategy to optimize the hydrophilicity, water-uptake capacity and air-purifying ability of metal-organic frameworks (MOFs) with long-term stability, offering an ideal candidate with autonomous multi-functionality of moisture control and pollutants sequestration. Through variant tuning of organic-linkers carrying hydrophobic and hydrophilic groups in the pore-nanospaces of prototypical UiO-67, a moderately hydrophilic MOF (UiO-67-4Me-NH 2 -38%) with high thermal, hydrolytic and acid-base stability is screened out, featuring S-shaped water sorption isotherms exactly located in the recommended comfortable and healthy ranges of relative humidity for indoor ventilation (45%-65% RH) and adverse health effects minimization (40-60% RH). Its exceptional attributes of water-uptake working capacity/efficiency, contaminates removal, recyclability and regeneration promise a great potential in confined indoor environment application.

Titanium metal-organic frameworks (Ti-MOFs), as an appealing type of artificial photocatalysts, have shown great potentials in the field of solar energy conversion due to their well-studied photo-redox activity similar to TiO 2 and good optical responsiveness of linkers serving as the antenna to absorb visible-light. Although enormous efforts have been dedicated to developing Ti-MOFs with high photocatalytic activity, their solar energy conversion performances are still poor. Herein, a covalent-integrated strategy has been implemented to construct a series of multivariate Ti-MOF/COF hybrid materials, PdTCPP⸦PCN-415(NH 2 )/TpPa (composites 1, 2, and 3), featuring excellent visible-light utilization, suitable band gap, and high surface area for photocatalytic H 2 production. Notably, the resulting composites demonstrated remarkably enhanced visible-light-driven photocatalytic H 2 evolution performance, especially for the composite 2 with the maximum H 2 evolution rate of 13.98 mmol g -1 h -1 (turn-over frequency (TOF) = 227 h -1 ), which is much higher than the prototypical counterparts, PdTCPP⸦PCN-415(NH 2 ) (0.21 mmol g -1 h -1 ) and TpPa (6.51 mmol g -1 h -1 ). Our work thereby suggests a new approach to develop highly efficient photocatalysts for photocatalytic H 2 evolution reaction and beyond.

Photochromic coordinative cages containing dynamic C Created by potrace 1.16, written by Peter Selinger 2001-2019 N imine bonds are assembled from a dithienylethene-based aldehyde and tris-amine precursors via metallo-component self-assembly. The resulting metal-templated cages are then reduced and demetalated into pure covalent-organic cages (COCs), which are otherwise difficult to prepare via de novo organic synthesis. Both the obtained coordinative and covalent cages can be readily interconverted between the ring-open (o-isomer) and one-lateral ring-closed (c-isomer) forms by UV/vis light irradiation, demonstrating distinct absorption, luminescence and photoisomerization dynamics. Specifically, the ring-closed c-COCs show a blue-shifted absorption band compared with analogous metal-templated cages, which can be applied in photoluminescence (PL) color-tuning of upconversion materials in different ways, showing potential for constructing multi-readout logic gate systems., Metal-templated component self-assembly and then demetalation affords photochromic covalent organic cages applicable for upconversion PL-color tuning for logic gates.

A flexible and robust microporous copper(II) metal-organic framework (MOF) based on a methyl-functionalized ligand, namely, [Cu3(μ3-OH)2(L)2(DMF)] (LIFM-ZZ-1; L = 2,2'-dimethyl-4,4'-biphenyldicarboxylic acid and DMF = N,N-dimethylformamide), was constructed. Its sorption performance for the separation of CH4, C2H6, and C3H8 was investigated. LIFM-ZZ-1 showed a breathing behavior that led to a transition between large- and narrow-pore states. The sample also showed outstanding water stability. Gas adsorption experiments revealed that desolvated LIFM-ZZ-1 exhibited higher adsorption capacities for C2H6 and C3H8 (2.80 and 4.06 mmol·g-1) than for CH4 (0.39 mmol·g-1) at 298 K and 1 bar. Breakthrough experiments showed that a CH4/C2H6/C3H8 mixture was completely separated at 298 K, demonstrating the promising potential applications of this material for separating low contents of C2/C3 hydrocarbons from natural gas.

In multiphoton excited fluorescence (MPEF), high-energy upconversion emission is obtained from low-energy excitation by absorbance of two or more photons simultaneously. In a pressure-induced fluorochromic process, the emission energy is switched by outer pressure stimuli. Now, five metal-organic frameworks containing the same ligand with simultaneous multiphoton absorption and pressure-induced fluorochromic attributes were studied. One-, two-, and three-photon excited fluorescence (1/2/3PEF) can be achieved in the frameworks, which exhibit pressure-induced blue-to-yellow fluorochromism. The performances are closely dependent with the topologies, flexibilities, and packing states of the frameworks and chromophores therein. The multiphoton upconversion performance can be intensified by pressure-related structural contraction. Over ten-fold increment in the 2PA active cross-section up to 2217 GM is achieved in pressed LIFM-114 compared with the 210 GM for pristine sample at 780 nm.

A zirconium-based metal–organic framework (Zr-MOF) with a 2-fold catenated breathing structure is designed, whose framework contracts in a similarly consecutive manner responsive to solvent (S), te...

Five cyclometalated Ir(III) complexes with high phosphorescence efficiencies have been synthesized from 1,3-bis(1-propyl-1H-benzo[d]imidazol-2-yl)benzene (Pro-MBImB) or 2-(2,4-Difluorophenyl)pyridine (Fppy) based ligands with different ancillary ligands. It was found that these complexes have a wide range of emitting wavelength, covering the whole visible region, with moderately long lifetime (81–2159 ns) and high quantum yield (75–89%). Especially, the introduction of electron withdrawing −COOEt group onto the ancillary ligand extends the emission wavelength and affords good red-light emitting properties, and the obtained CIE (Commission Internationale de L'Eclairage) coordinates of (0.69, 0.31) in complex 2 are close to the standard red light and approaching near infrared region.

Five transition metal coordination polymers, {[Cu(4-pmntd)2(NO3)2]∙2CHCl3}n (1), {[Cu(4-pmntd)2(NO3)2]·3C7H8}n (2), {[Cu(4-pmntd)2(CF3SO3)(H2O)]·CF3SO3·H2O·CH3OH}n (3), [Cd(4-pmntd)2]n·nSiF6·x(CH3OH)·y(CHCl3) (4), and [Zn(4-pmntd)2(CF3SO3)2]n·x(solvent) (5), have been obtained from a ditopic ligand, N,N'-bis(4-pyridylmethyl)naphthalene diimide (4-pmntd). Either sql- or dia- structures are generated from four connecting coordination nodes of the metal centers. While delicate interpenetration and structural tuning in these complexes is achieved by the different conformations and spatially extending geometries adopted by the ligand and “secondary building process” induced by pillar-like anions.

We demonstrate herein a facile strategy to engineer versatile catalytically active coordination interspace in the same primitive metal-organic framework (MOF) for variable heterogeneous catalysis. Different functional ligands can be reversibly inserted into and removed from proto-LIFM-28 individually or successively to bring in single or binary catalytic sites for specific reactions and switch the parent MOF to multipurpose catalysts. Alcohol-oxidation, Knoevenagel-condensation, click, acetal, and Baylis-Hillman reactions are achievable through simple exchange of a single catalytic spacer, while sequential or stepwise reactions are designable via selective combination of two catalytic spacers with different functionalities, thus making proto-LIFM-28 a multivariate MOF for multiuse and economic catalysis.

The effect of framework (pore) disorder on gas sorption of azole-based isoreticular Cu(II) MOFs with rtl (rutile) topology and characteristic 1D tubular pore channels is investigated for the first time., Metal–organic frameworks with highly ordered porosity have been studied extensively. In this paper, the effect of framework (pore) disorder on the gas sorption of azole-based isoreticular Cu(II) MOFs with rtl topology and characteristic 1D tubular pore channels is investigated for the first time. In contrast to other isoreticular rtl metal–organic frameworks, the Cu(II) metal–organic framework based on 5-(1H-imidazol-1-yl)isophthalate acid has a crystallographically identifiable disordered framework without open N-donor sites. The framework provides a unique example for investigating the effect of pore disorder on gas sorption that can be systematically evaluated. It exhibits remarkable temperature-dependent hysteretic CO2 sorption up to room temperature, and shows selectivity of CO2 over H2, CH4 and N2 at ambient temperature. The unique property of the framework is its disordered structure featuring distorted 1D tubular channels and DMF-guest-remediated defects. The results imply that structural disorder (defects) may play an important role in the modification of the performance of the material.

Despite great progress, the development of anode materials with excellent properties for high-performance lithium-ion batteries (LIBs) remains challenging. Rational design and synthesis of novel hybrid nanomaterials that synergistically integrate the structural/compositional advantages of their components provides exciting opportunities and solutions. Here, we demonstrate a dilute atmosphere pyrolysis strategy for the one-step synthesis of a new hybrid nanomaterial, CoO/C yolk–shell nanostructures (CoO/C YSNSs), from a Co-containing metal–organic framework precursor, ZIF-67. The CoO/C YSNSs integrate CoO and carbon into a unique hierarchical and quasi-homostructural architecture, in which both the yolk and shell comprise ultrafine CoO nanoparticles homogeneously embedded in highly porous, conductive and N-doped carbon. Benefiting from such structural and compositional features, CoO/C YSNSs deliver ultrahigh and stable lithium storage performances (retained capacity up to 1970 and 680 mA h g−1 even after 1000 charge/discharge cycles at a current density of 100 and 1000 mA g−1, respectively), and rank among the best cobalt oxide-based anode materials. The formation of CoO/C YSNSs is also investigated and attributed to two synergistic processes of dynamic redox competition and heterogeneous contraction. Our work provides new stimuli to the development of complex hybrid nanostructure-based advanced electrode materials for high-performance batteries.

An in situ approach has been undertaken to synthesize a series of metal–organic frameworks (MOFs) with the pore surface functionalized via the organic linkers of multi N-heterocycles. This was done so as to explore their stability, flexibility, and adsorption behaviors on the basis of the nature of metal centers (M = Zn, Mg, Co, Ni). Four isoreticular MOFs based on in situ synthesized T-shaped ligands were obtained, and their phase purity and stability were investigated in conjunction with the adsorption properties for a wide range of gases (Ar, N2, H2, CO2, CH4, C2H6, C2H4, C3H8, and C3H6). The results revealed that the stability of MOF based on Ni2+ is better than those of Mg, Zn, and Co analogues, and that the multi N-heterocycles ligand endows these MOFs with higher affinity for CO2, C2H6, C2H4, C3H8, and C3H6, leading to an excellent selectivity for these gases over CH4.

A flexible-robust copper(II) metal-organic framework, denoted as LIFM-100, has been successfully synthesized using a fluorinated linear dicarboxylate to link copper ions. LIFM-100 exhibits a breathing effect, which can transform reversibly between a large form (lp) and a narrow form (np) from single crystal to single crystal. In addition, LIFM-100 shows good thermal and chemical stability. By the introduction of trifluoromethyl functional groups and uncoordinated carboxyl acids, LIFM-100 features a good CO

A Au(i)-N-heterocyclic-carbene (NHC)-edged Pd

Summary Metal-organic frameworks (MOFs) have intriguing and tunable photophysical properties owing to predesignable structures from well-defined metal and/or organic chromophores. We propose a one-pot two-step assembly strategy for engineering dual-functional coordination interspace where two kinds of organic linkers are segregated in predefined positions. This design endows the three-dimensional coordination framework with unidirectional deformation character, leading to an orientation-dependent and pressure-responsive photoluminescence color change. For the first time, unique piezofluorochromic anisotropism is achieved and can be accumulated stepwise and visualized by a metal-organic framework single crystal, providing a basic model for application in stimuli-responsive photoluminescence sensing, barcoding, signal switching, harvesting, and magnifying micro-devices.

A rhodium(III)-porphyrin zirconium metal-organic framework (Rh-PMOF-1(Zr)) has been prepared from the self-assembly of a Rh-based metalloporphyrin tetracarboxylic ligand Rh(TCPP)Cl (TCPP = tetrakis(4-carboxyphenyl)porphyrin) with ZrCl4. The framework of Rh-PMOF-1 is stable up to 270 °C as disclosed by the variable-temperature powder X-ray diffraction (VT-PXRD) measurements, and possesses good chemical stability over a wide range of solvents including water. The single-crystal structural analysis reveals that Rh-PMOF-1 contains 3-D channels (1.9 × 1.9 nm2), and the Rh-porphyrin units are exposed to the cavities. The calculation based on the N2 adsorption at 77 K shows Rh-PMOF-1(Zr) has a high BET surface area (3015 m2g−1). The luminescence decay of Rh-PMOF-1 is well fitted to a tri-exponential curve featuring a long average lifetime of 207 μs at 298 K under vacuum, which represents a rare example of room-temperature phosphorescence of Rh-porphyrin complexes. Under 1 atm, it displays CO2 uptake up to 42, 53 and 98 cm3g−1 at 308, 298 and 273 K, respectively. Catalytic results show that, under the visible light (≥400 nm) irradiation without any additional photosensitizer, Rh-PMOF-1 is powerful to catalyze CO2 reduction to the formate ion with up to 99% selectivity, and can be recycled and reused for 3 runs. Theoretical study was further carried out to reveal the energy levels of the frontier orbitals of Rh-PMOF-1 and the preferred binding sites of CO2 in the framework.

Nanoreactors constructed by encapsulation of catalytic species in hierarchically porous metal–organic framework (HPMOF) nanostructures have emerged as a type of promising catalysts that deliver enhanced conversion and excellent selectivity/stability. However, the controlled synthesis of small HPMOF nanocrystals with tunable size and nanostructures remains challenging. Here, by coupling external ultrasonication with the inherent binding competitions between the metal ions of bimetallic Co/Zn-ZIF, we design and develop a new strategy, dynamic growth, for the facile synthesis of small (down to ca. 95 nm), single-crystalline and structure-/size-tunable HPMOF nanocrystals through a one-pot, additive-free procedure. Benefiting from the combined structure/size regulation, nanoreactors based on our small nanocrystals of meso-HP-Co/Zn-ZIF-50% are able to deliver exceptional conversion while keeping their excellent selectivity and stability. Insights gained from this work opens a new avenue for the development of c...

A series of bipyridine platinum(II) complexes with different sizes of triangular metallacycles and alkyl/oligoether chains has been synthesized and characterized. They are packed in a zig-zag fashion with the formation of dimeric structures according to their X-ray crystal structures. Different emission origins are observed due to the different sizes of the triangular ligands. Their morphologies could be tuned by the modification of the molecular structures with different metallacyclic alkynyl ligands and alkyl/oligoether chains and solvents. More interestingly, unusual electronic absorption changes and upfield shifts of the aromatic proton resonances are observed upon increasing the temperature, suggesting further aggregation of the architectures. Near-infrared (NIR) emission is also realized through the tuning of the π-π stacking, Pt⋅⋅⋅Pt interactions, and the packing of planar metallacycles.

A metalloporphyrin Cu5-cluster based MOF (metal–organic framework), [Cu4.5((H4TZPP)(TZPP)Cl2)(H2O)0.5]·CH3NH2CH3·7EtOH·8H2O (LIFM-WZ-3) was synthesized from the tetrapodal ligand 5,10,15,20-tetrakis[4-(2,3,4,5-tetrazolyl)phenyl]porphyrin (H6TZPP) and copper chloride. LIFM-WZ-3 exhibits a rare 2D + 3D → 3D interpenetration topology, of which the frl-type 3D MOF and a layered 2D HOF (hydrogen bond organic framework) are intertwined, leading to an anionic framework with 1D spindle-like channels. Powder X-ray diffraction analysis reveals that the framework is stable in acid, base and various organic solvent environments. LIFM-WZ-3 exhibits moderately high separation performances for CO2/CH4, CO2/N2, C3H6/CH4, C2H6/CH4, and C2H4/CH4 at room temperature. Specifically, the anionic framework in LIFM-WZ-3 containing dimethylamine cations can selectively adsorb cationic organic dyes from aqueous pollutants for recycle purpose. The high adsorption capacity for methylene-blue (MB+, 983 mg g−1) and crystal violet (CV+, 713.5 mg g−1) ranks the highest among those MOFs ever reported.

Through dynamic spacer installation, five fluorescent metal-organic frameworks (MOFs) have been constructed based on a proto-MOF LIFM-28 and multivariate ligands as fluorophores. The emissions are tunable via insertion of fluorescent ligands, demonstrating a versatile approach for luminescence tuning by virtue of dynamic spacer installation using swing-role MOFs.

A three-dimensional functional metal–organic framework (LIFM-38) has been successfully synthesized with a fluorinated bicarboxylate ligand. LIFM-38 exhibits good stability and a surface area of 803 m2 g–1. Owing to the synergistic effect of different functional groups, cocrystallized amine active sites, and suitable pore space, LIFM-38 shows good selective CO2 and C2+ hydrocarbons adsorption over CH4 and N2; in addition, LIFM-38 exhibits good selective C3 hydrocarbons adsorption over C2 hydrocarbons.

A 3D porous perchlorinated metal–organic framework (MOF), LIFM-26, featuring dual functionality, that is, functional polar groups and open metal sites, has been synthesized using perchlorinated linear dicarboxylate to link trigonal prismatic Fe3(μ3-O) units. LIFM-26 exhibits good thermal and chemical stability, and possesses high porosity with a BET surface area of 1513 m2 g−1, compared with isoreticular MOF-235 and Fe3O(F4BDC)3(H2O)3 (F4BDC=2,3,5,6-tetrafluorobenzene-1,4-dicarboxylate). Most strikingly, LIFM-26 features good gas sorption/separation performance at 298 K and 1 atm with IAST selectivity values reaching up to 36, 93, 23, 11, 46, and 202 for CO2/CH4, CO2/N2, C2H4/CH4, C2H6/CH4, C3H8/CH4, and R22/N2 (R22=CHClF2), respectively, showing potential for use in biogas/natural gas purification and CO2/R22 capture.

Near-infrared (NIR) luminescence detection of picric acid (PA) was achieved sensitively and selectively by using a nanosized Nd-III metal-organic cage (MOC) for the first time.

A robust iridium(iii)-porphyrin metal–organic framework acts as a selective catalyst for carbenoid insertion into primary Si–H bonds with excellent effectivity., An iridium-porphyrin ligand, Ir(TCPP)Cl (TCPP = tetrakis(4-carboxyphenyl)porphyrin), has been utilized to react with HfCl4 to generate a stable Ir(iii)-porphyrin metal–organic framework of the formula [(Hf6(μ3-O)8(OH)2(H2O)10)2(Ir(TCPP)Cl)3]·solvents (Ir-PMOF-1(Hf)), which possesses two types of open cavities (1.9 × 1.9 × 1.9 and 3.0 × 3.0 × 3.0 nm3) crosslinked through orthogonal channels (1.9 × 1.9 nm2) in three directions. The smaller cavity is surrounded by four catalytic Ir(TCPP)Cl walls to form a confined coordination space as a molecular nanoreactor, while the larger one facilitates reactant/product feeding and release. Therefore, the porous Ir-PMOF-1(Hf) can act as a multi-channel crystalline molecular flask to promote the carbenoid insertion reaction into Si–H bonds, featuring high chemoselectivity towards primary silanes among primary, secondary and tertiary silanes under heterogeneous conditions that are inaccessible by conventional homogeneous catalysts.

With the idea of supramolecular hosts encircling monoanions, a series of urea-containing trinuclear cationic copper complexes were designed, prepared and structurally analyzed. Copper(I) acetylides [Cu3(μ-dppm)3(μ3-η1-CCC6H4-4-NHC(O)NHC6H4-4-R)2]+ (dppm = bis(diphenylphosphino)methane; R = NO2 (1), CF3 (2), Cl (3), H (4), tBu (5), and OCH3 (6)) were prepared with F−, BF4−, or NO3− present as the anion. Eight 1-D anion coordination polymers (ACPs), 1·F, 2·F, 3·BF4, 4·F, 5·F, 5·BF4, 5·NO3 and 6·0.5F·0.5BF4, were clearly determined by X-ray diffraction. Diversity in the polymeric architecture is generated by both the choice of R-group used and anion present. 2·F, 3·BF4, 4·F, and 5·F show linear 1-D structures; 5·BF4 and 5·NO3 feature single-stranded helical structures; 1·F and 6·0.5F·0.5BF4 exhibit meso-helical structures. Solid state UV-vis absorption and luminescence properties are also discussed.

Through stepwise post-synthetic spacer insertion and click reactions, six Zr-MOFs with different types and amounts of functional groups have been constructed based on proto-MOF PCN-700. Their gas adsorption capacities and selectivities have been greatly improved and finely tuned, demonstrating the combinatorial effect of pore surface modification and pore space partition.

International audience; An hourglass porous metal-organic framework, LIFM-12, constructed on a T-shaped flexible ligand with Cu 2+ paddle-wheel clusters, shows temperature and gas adsorption responsive structural dynamics upon reversible molecular guest binding. Temperature-dependent single crystal and powder X-ray diffraction experiments show that the open gate status of the framework with adaptive behaviours facilitates kinetic diffusion of gas molecules resulting in the sequential filling of pores of different sizes, thus creating a breathing behaviour reminiscent of the observation of several steps in adsorption isotherms. In addition, adsorption studies revealed that LIFM-12 performs exceptional adsorption selectivity of 10-25 for CO 2 versus light gases N 2 , CH 4 , and CO and up to 200 for C 3 H 6 versus CH 4 .

An hourglass porous metal-organic framework, LIFM-12, constructed on a T-shaped flexible ligand with Cu

A trifluoromethyl functionalized linker and Cu-O chain composed MOF, LIFM-100, was used as "crystalline sponge" to determine eight hardly crystallized liquids' configurations based on its flexibility conformation, suitable pore size, electron-rich channel environment, and low symmetric space group. The H bond interactions between host-guest and guest-guest were well analyzed.