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Known for excellent stability, porosity and functionality, the high-valent Zr4+ metal-organic frameworks (Zr-MOFs) still meets synthetic challenge in modulating the strength of Zr-Ocarboxylate linkage. Herein we explore the unusual coordination dynamics of fluorinated Zr-MOFs by designing two trifluoromethyl modified ligands with distinct geometry preference to form a family of thermodynamic and kinetic products. The low-connecting kinetic Zr-MOFs possess substitutable coordination sites to endow Zr6 -cluster with extra dynamic behaviors, thus opening a post-synthetic pathway to sequential reassembly/disassembly processes. Comprehensive factors, including ligand geometry, Zr6 -cluster connectivity, acid modulator and reaction temperature/concentration, have been studied for controllable syntheses. The stability, hydrophobicity and gas adsorption/separation properties of obtained Zr-MOFs are explored. This work sheds light on the understanding of the dynamic coordination chemistry of Zr-MOFs beyond strong Zr-O bond, which poses a versatile platform for modification and functionalization of Zr-MOFs.

Two-dimensional (2D) materials have been widely applied in electrochemical conversion technologies, especially toward the water oxidation reaction (WOR) in metal–air batteries and water splitting. Here, we demonstrate a facile ligand-assisted synthetic method, promoting the transformation of 2D layered double hydroxides (LDHs) into 2D metal–organic frameworks (MOFs). The CoFe-LDH precursor acts as an adjustable metal release source, controlling heterogeneous nucleation for 2D MOFs. Compared with most cobalt-based electrocatalysts, the optimized CoFe 2D MOFs exhibit a superior WOR performance on glassy-carbon electrodes (overpotential of 274 mV at 10 mA cm−2 and a Tafel slope of 46.7 mV dec−1) and long-term stability, due to the unique 2D characteristics and coupling effect between Co and Fe ions. More importantly, this work highlights the ability to transform 2D LDHs into 2D MOFs and reveals the intrinsic factors for excellent performance in the WOR.

Selective hydrogenation of α,β-unsaturated aldehydes to achieve high selectivity towards a desirable product is still a great challenge mainly because of the complex conjugate system. Herein, Rh nanoclusters encapsulated in MIL-101 (Cr), synthesized by the double solvent method, are able to selectively hydrogenate CC of cinnamaldehyde, an α,β-unsaturated aldehyde and achieve over 98% selectivity with a conversion of 98% to a saturated aldehyde under mild conditions. Fourier transform infrared spectroscopy confirms that MIL-101 acts as an aldehyde protector to suppress the reactivity of CO, and the X-ray photoelectron spectroscopy (XPS) data indicate that the electropositive Rh, owing to the electron transfer from Rh to MIL-101, preferentially absorbs CC rather than CO leading to improvement of the selectivity towards saturated aldehydes. In addition, Rh@MIL-101 can also efficiently catalyse hydrodefluorination of aryl fluorides with good stability. This work provides a basic strategy to develop other selective heterogeneous catalysts via structural modulation for synergetic catalysis.

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,...

International audience; The development of cost-effective, high-performance, and robust bifunctional electrocatalysts for overall water splitting remains highly desirable yet quite challenging. Here, by selecting appreciate precursors of dopamine and a Co-containing metal-organic framework of ZIF-67, we subtly couple their reaction processes to develop a facile approach for the synthesis of a hollow CoP nanostructure with N-doped carbon skeleton (H-CoP@NC). Benefiting from the highly porous nanostructure and conductive carbon skeleton, H-CoP@NC is capable of working as highly active and durable bifunctional electrocatalyst for both hydrogen and oxygen evolution reaction. When further used as the electrocatalyst for overall water splitting, H-CoP@NC delivers excellent activity (cell voltage of 1.72 V at a current density of 10 mA cm(-2)), close to that of the noble-metal-based benchmark catalyst couple of Pt/C parallel to RuO2. Our work thus provides new insights into the development of transitional metal phosphides based hollow hybrid nanostructures, particularly those with multiple functionalities in sustainable energy conversion technologies and systems.

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.

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.

Luminescent thermometers have attracted much attention, because of their fast response, high sensitivity, and noninvasive operation, relative to other traditional thermometers. The extensive studies on the temperature-dependent luminescent properties of Cu(I) complexes make this low-cost metal source a promising candidate as a component of thermometers. Herein, we prepared three luminescent phosphinine Cu(I) complexes whose emission lifetimes are precisely dependent on the temperature variations. For practical utilization, sensor films have been fabricated by doping these Cu(I) complexes into the matrices of polyacrylamide. These films not only exhibit excellent linear correlations between the temperature and emission lifetime over the wide range of 77-337 K, but also show high sensitivity (with the best one to -6.99 μs K-1). These are essential factors for the application in luminescent molecular thermometers. Moreover, the emission mechanism for these Cu(I) complexes are rationalized by the combination of experimental and theoretical results.

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 Co-MOF, [Co3(HL)2·4DMF·4H2O] was simply synthesized through a one-pot solvothermal method. With the semiconductor nature, its band gap was determined to be 2.95 eV by the Kubelka–Munk method. It is the first trinuclear Co-MOF employed for photocatalytic hydrogen evolution and CO2 reduction with cobalt–oxygen clusters as catalytic nodes. Hydrogen evolution experiments indicated the activity was related to the photosensitizer, TEOA, solvents, and size of catalyst. After optimization, the best activity of H2 production was 1102 μmol/(g h) when catalyst was ground and then soaked in photosensitizer solution before photoreaction. To display the integrated design of Co-MOF, we used no additional photosensitizer and cocatalyst in the CO2 reduction system. When −NH2 was used for light absorption and a Co–O cluster was used as catalyst, Co-MOF exhibited an activity of 456.0 μmol/(g h). The photocatalytic mechanisms for hydrogen evolution and CO2 reduction were also proposed.

A bright blue emitting excited-state intramolecular proton transfer (ESIPT) molecule, 2-(4,5-bis(4-chlorophenyl)-1H-imidazol-2-yl)-4-chlorolphenol (HPICl) has been designed and synthesized, whose solvent-dependent PLQY is up to 0.53 in EtOH, and 0.46 as solid state. Fluorescence quenching experiments manifest the selective detection of picric acid (PA) and p-nitrophenol (p-NP) over other nitroaromatic explosive compounds, which is closely related with the presence of OH groups on these two molecules that affect the ESIPT-based luminescence character of HPICl.

Searching for highly active and stable bifunctional electrocatalysts for overall water splitting, e.g., for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), is dominating in terms of bringing future renewable energy storage and conversion processes to reality. In this work, a kind of two-dimensional ultrathin manganese (Mn) doped polyhedral cobalt phosphide (Mn-CoP) has been synthesized via the etching-carbonization-phosphidation of Co-centered metal-organic frameworks. The as-prepared porous Mn-CoP nanosheets had a larger specific surface area and higher porosity, furnishing them with more plentiful catalytically active sites than their counterpart hollow CoP and Mn-CoP nanoparticles, and thus showed much better electrocatalytic activity for both HER and OER in acidic and alkaline media. In addition, the Mn-CoP nanosheets also demonstrated excellent durability after long-term operation. These high performances are attributed to the synergistic effects of the CoP nanosheets with intrinsic activity, the graphitic carbon and the controllable electronic structure doped by Mn and N elements. This synthetic methodology of using a classical MOF as a precursor to build a new 2D sheet-like composite may create opportunities to search for highly efficient and robust non-precious metal catalysts for energy-related reactions.

A facilely available zwitterionic ligand, 1,1′-(1,4-phenylenebis(methylene))dipyridin-4(1H)-one (PBPO), has been designed to bear intraligand charge transfer (ILCT) energy states. PBPO was used to assemble two series of Ln(III) complexes with either 2D (6,3)-hcb network (LIFM-24(Ln), Ln = Pr, Nd, and Sm), or 1D loop-and-chain (LIFM-25(Ln), Ln = Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) polymeric structures, as determined by the radius of the lanthanide ions. Highly efficient photoluminescence (PL) in the visible to near-infrared (NIR) regions can be obtained in these Ln-complexes, due to the extended energy transfer from both the triplet and ILCT states of the zwitterionic ligand. Among these complexes, LIFM-24(Pr) and LIFM-25(Dy) display excitation-dependent color tunable luminescence and white-light emission based on the combination of ligand-centered (LC) and metallic-centered (MC) emissions. Uniquely, a strict linear relationship was established between the excitation wavelength and the emission CIE (Commission Internationale de L'Eclairage) coordinates in a wide color range (orange to blue for LIFM-24(Pr), and yellow to blue for LIFM-25(Dy)), thereby providing prototype models for programmable PL color tuning and white-light emission, which are rarely achievable in homometallic Ln-complexes.

Tripodal ligand triCB-NTB (4,4′,4″-(2,2′,2″-nitrilotris(methylene)tris(1H-benzo[d]imidazole -2,1-diyl)tris(methylene))tribenzoic acid) was applied to assemble Pb(II) or Cd(II) coordination complexes, resulting in single-component near white light emission.

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.

By anchoring lanthanide coordination monomers onto a PMMA polymer backbone via a pre-designed vinylbenzyl-substituted NTB-type ligand, we succeeded in the fabrication of homo or hetero Ln-metallopolymers that can emit tunable and designable multicoloured photoluminescence as well as white light emission. Copolymerization results in the fine-tuning of the energy state of the ligand in the metallopolymer compared with that in the coordination monomer, thereby changing the energy transfer efficiency to Eu3+ and Tb3+ centers in opposite ways. And further designing of hetero-lanthanide metallopolymers leads to additional energy transfer between Eu3+ and Tb3+, facilitating the generation of pure white light emission. In general, the facile and controllable synthesis procedure, versatile and reproducible combination of lanthanides, ligands and polymer backbones, and relatively high white light emitting luminous efficiency (>5%) prove this method to be promising in future lighting WPLED applications.

We present herein a fine-tuning model for the fabrication and application of Er(III)/Tm(III)-Yb(III) co-doped ZrO2 macroporous matrix, which combines porosity and highly efficient multi-color to white light upconversion photoluminescence. By control of lanthanide doping species and concentration, as well as the excitation pumping power, the emission can be tuned among red, green or blue (RGB) primary colors in a linear fashion, and trichromatically combined white light is therefore achieved. Precise mathematical matrix models are established for prediction of color chromaticity coordinates as a relation of doping composition and pumping power, which provides a general route for the development of novel upconversion materials that are particularly useful in white light displaying, multiplexed labelling and anti-counterfeiting.

Multi-mode photoluminescence, including enolemission, keto-emission, and aggregate-related emission is achieved in a Zn-II coordination polymer from excited-state intramolecular proton transfer (ESIPT) ligands. Single-phase white light emission (WLE) and tunable emitting colors can be obtained by varying the suspending/grinding solvent system or temperature, which brings a brand-new model in developing multi-stimuli-responsive WLE materials.

Five cyclometalated Ir(III) complexes are synthesized from a sulfonate-modified bis-benzimidazole-type organic ligand (3,3′-(2,2′-(1,3-phenylene)bis(1 H –benzo [ d ]imidazole-2,1-diyl))dipropane-1-sulfonic acid, MBS) with different ancillary ligands, and can be classified into two categories. Namely, complexes 1 and 2 (MBS-Ir-ppy and MBS-Ir-Fppy), which are electroneutral, and complexes 3–5 (MBS-Ir-bpy, MBS-Ir-Mebpy, and MBS-Ir-bpyCOOEt), which are cationic and soluble in water. These Ir(III) complexes show tunable luminescence from cyan to orangish red color in solution and yellowish red to pure red color in solid state, with moderately long lifetime (56–528 ns) and high quantum yield (35–71%).

The exploration of novel porous core–shell materials is of great significance because of their prospectively improved performance and extensive applications in separation, energy conversion, and catalysis. Here, mesoporous metal–organic frameworks (MOFs) NH2‐MIL‐101(Fe) as a core generate a shell with mesoporous covalent organic frameworks (COFs) NUT‐COF‐1(NTU) by a covalent linking process, the composite NH2‐MIL‐101(Fe)@NTU keeping retentive crystallinity with hierarchical porosity well. Importantly, the NH2‐MIL‐101(Fe)@NTU composite shows significantly enhanced catalytic conversion and selectivity during styrene oxidation. It is mainly due to the hydrophilic MOF nanocrystals readily gathering the hydrophobic reactants styrene and boosting the radical mechanism path after combining the hydrophobic COFs shell. The synthetic strategy in this systematic study develops a new rational design for the synthesis of other core–shell MOF/COF‐based hybrid materials, which can expand the promising applications.

Long persistent luminescence (LPL) materials have a unique photophysical mechanism to store light radiation energy for subsequent release. However, in comparison to the common UV source, white-light (WL) and near-infrared (NIR) excited LPL is scarce. Herein we report a metal-organic supramolecular box based on a D-π-A-type ligand. Owing to the integrated one-photon absorption (OPA) and two-photon absorption (TPA) attributes of the ligand, the heavy-atom effect of the metal center, as well as π-stacking and J-aggregation states in the supramolecular assembly, LPL can be triggered by all wavebands from the UV to the NIR region. This novel designed supramolecular kit to afford LPL by both OPA and TPA pathways provides potential applications in anti-counterfeiting, camouflaging, decorating, and displaying, among others.

A highly fluorescent HPI-based excited-state intramolecular proton transfer (ESIPT) molecule is designed and adopted as a naked-eye colorimetric sensor to distinguish methanol, ethanol and isopropanol vapors. Amplified spontaneous emission was also observed for the C1-form single crystal of the molecule attributed to its intrinsic four-level energy states.

Distinguishable d → f or f → d energy transfer processes depending on lanthanide ions are observed in isomorphous d–f heterometallic complexes containing the Ru(II) metalloligand (LRu), which lead to sensitized NIR emission (for Nd3+ and Yb3+) or enhanced red emission of LRu (for Eu3+ and Tb3+), and represent the first eye-detectable evidence of f → d energy transfer processes in Ln–Ru bimetallic complexes. Based on the systematic luminescence and decay lifetime study, cascade f → d → f energy transfer has been proposed in Ln1–Ru–Ln2 trimetallic systems for improved NIR sensitization.

Two-dimensional (2D) metal–organic frameworks have exhibited a range of fascinating attributes, of interest to numerous fields. Here, a calcium-based metal-organic framework with a 2D layered structure has been designed. Dual emissions relating to intralayer excimers and interlayer trapped excitons are produced, showing excitation-dependent shifting tendency, characteristic of a low dimensional semiconductor nature. Furthermore, the layer stacking by weak van der Waals forces among dynamically coordinated DMF molecules enables exfoliation and morphology transformation, which can be achieved by ultrasound in different ratios of DMF/H2O solvents, or grinding under appropriate humidity conditions, leading to nano samples including ultrathin nanosheets with single or few coordination layers. The cutting down of layer numbers engenders suppression of interlayer exciton-related emission, resulting in modulation of the overall emitting color and optical memory states. This provides a rare prototypical model with switchable dual-channel emissions based on 2D-MOFs, in which the interlayer excitation channel can be reversibly tuned on/off by top-down exfoliation and morphology transformation.

Core–shell or striped heteroatomic lanthanide metal–organic framework hierarchical single crystals were obtained by liquid-phase anisotropic epitaxial growth, maintaining identical periodic organization while simultaneously exhibiting spatially segregated structure. Different types of domain and orientation-controlled multicolor photophysical models are presented, which show either visually distinguishable or visible/near infrared (NIR) emissive colors. This provides a new bottom-up strategy toward the design of hierarchical molecular systems, offering high-throughput and multiplexed luminescence color tunability and readability. The unique capability of combining spectroscopic coding with 3D (three-dimensional) microscale spatial coding is established, providing potential applications in anti-counterfeiting, color barcoding, and other types of integrated and miniaturized optoelectronic materials and devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A convenient, fast and selective water analysis method is highly desirable in industrial and detection processes. Here a robust microporous Zn-MOF (metal–organic framework, Zn(hpi2cf)(DMF)(H2O)) is assembled from a dual-emissive H2hpi2cf (5-(2-(5-fluoro-2-hydroxyphenyl)-4,5-bis(4-fluorophenyl)-1H-imidazol-1-yl)isophthalic acid) ligand that exhibits characteristic excited state intramolecular proton transfer (ESIPT). This Zn-MOF contains amphipathic micropores (, Fast and sensitive detection of water molecules in organic solvents and gases remains an important challenge. Here, Pan and co-workers design a metal-organic framework capable of ultrafast and reversible water sensing by photoluminescence switching via an excited state intramolecular proton transfer mechanism.

We demonstrate that the conformation, packing mode, and blue fluorescence of a soft piezofluorochromic compound can be preserved by structurally fixing it into a solid calcium metal–organic framework (Ca-MOF, LIFM-40), which can survive pressures up to 8 MPa. DFT calculations have been combined with experimental results to indicate that the ligands adopting a specific conformation and packing without π···π interactions are the reasons for its rigidified blue emission.

A sacrificial template strategy is developed for the synthesis of yolk-shell Au@ZIF-8 nanoreactor. The Au@ZIF-8 nanoreactor possesses single-crystalline metal-organic framework (MOF) shell with intrinsic monodisperse micropores and introduced macropores. In each of the macropores, one Au NP is encapsulated to form a nanoreactor unit. The quantity of the reactor units in the MOF shell can be readily regulated. Such structure features of the Au@ZIF-8 nanoreactor facilitate the size selectivity of reactants, the accessibility of Au nanoparticles to reactants, and the mass transfer of reactants and products. As a result, the Au@ZIF-8 nanoreactor delivers excellent size selectivity, enhanced conversion, and good cycling stability when used to catalyze the aerobic oxidation of alcohols with different molecular size.

We report herein an unprecedented example of a luminescent Sm(III) metal-organic framework (Sm-MOF), in which both the visible and near-infrared (NIR) emissions of Sm(3+) ions are able to be sensitized by an excited-state intramolecular proton transfer (ESIPT) ligand. Due to the solvent-mediated interchange between enol and keto excited states of the ligand and subsequent energy transfer rate to Sm(3+) ions, the luminescent decay lifetime of the Sm-MOF can be tuned in different solvent-grinding systems.

The capacity of anode materials plays a critical role in the performance of lithium-ion batteries. Using the nanocrystals of oxygen-free metal-organic framework ZIF-67 as precursor, a one-step calcination approach toward the controlled synthesis of CoO nanoparticle cookies with excellent anodic performances is developed in this work. The CoO nanoparticle cookies feature highly porous structure composed of small CoO nanoparticles (≈12 nm in diameter) and nitrogen-rich graphitic carbon matrix (≈18 at% in nitrogen content). Benefiting from such unique structure, the CoO nanoparticle cookies are capable of delivering superior specific capacity and cycling stability (1383 mA h g(-1) after 200 runs at 100 mA g(-1) ) over those of CoO and graphite.