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Elucidating the structure–property relationships of ultra-small metal nanocluster with basic nuclear is of great significance for understanding the evolution mechanism in both the structures and properties of polynuclear metal nanoclusters. In this study, an ultra-small copper hydride (CuH for short) nanocluster was simply synthesized with high yield, and the large-scale preparation was also achieved. Single crystal X-ray diffractometer (SC-XRD) analysis shows that this copper NC contains a tetrahedral Cu4 core co-capped by four PPh2Py ligands and two Cl in which the existence of the central H atom in tetrahedron was further identified experimentally and theoretically. This CuH nanocluster exhibits bright yellow emission, which is proved to be the mixture of phosphorescence and fluorescence by the sensitivity of both emission intensity and lifetime to O2. Furthermore, the temperature-dependent emission spectra and density functional theory (DFT) calculations suggest that the luminescence of CuH mainly originates from the metal-to-ligand charge transfer and cluster-centered triplet excited states. This work offers new insights into understanding the structure–property relationship of basic nuclear CuH nanocluster. [ABSTRACT FROM AUTHOR]

A low operating temperature and short response/recovery time are essential factors for sensors. Hence, it is necessary to create a sensor that can quickly detect target gas at a relatively low temperature. In this work, Co3O4 microtube based sensors were fabricated by a bio-template method using absorbent cotton. Co3O4 microtube sensors prepared in different concentrations of a salt solution displayed different sensitivities to triethylamine (TEA). The Co3O4-0.10 microtube sensor exhibited excellent sensitivity to TEA at 160 °C. The response of the Co3O4-0.10 sensor to 100 ppm TEA gas was 31.27 and the detection limit of TEA was 50 ppb. Meanwhile, the Co3O4-0.10 sensor also showed a short response/recovery time, such as 95 s/38 s to 100 ppm TEA, high selectivity, a good linear relationship (R2 = 0.994 for 1–100 ppm TEA and R2 = 0.991 for 50–1000 ppb TEA gas), fine repeatability and long-term stability, and strong humidity resistance. Thus, Co3O4 microtube based sensors prepared using a bio-template method have potential application prospects for the detection of TEA gas. [ABSTRACT FROM AUTHOR]

A fluorogenic RNA aptamer nanodevice integrating an entropy-driven RNA amplifier with near-infrared (NIR) light control was developed, affording high contrast and sensitivity for imaging low-abundance mRNA in living cells. The design principle offers a new approach for developing low-background imaging systems for live-cell studies and manipulation. [ABSTRACT FROM AUTHOR]

To expand the structural diversity and optimize the material performance, it is essential but challenging to regulate MOF structures in a predictable and controllable manner. In this work, by manipulating the substituents to engineer the ligand conformations, we designed and synthesized two asymmetric tricarboxylate ligands, and used them to successfully target two copper–tricarboxylate frameworks with diversified topologies depending on the ligand conformations. Besides, the ligand asymmetry induced the formation of two uncommon kinds of copper–carboxylate clusters, thus greatly expanding the library of copper–carboxylate secondary building units. Furthermore, the two compounds also displayed tunable gas adsorption properties pertinent to C2H2 separation and purification. At 298 K and 1 atm, the uptake capacity of C2H2 varies from 79.5 to 104.6 cm3 (STP) g−1, while the adsorption selectivities of C2H2 with respect to CO2 and CH4 are in the range of 2.3–3.8 and 15.3–21.6 for the equimolar components, respectively. Compared to the nitro counterpart, the methoxy MOF features higher C2H2 uptake capacity, larger C2H2/CO2 and C2H2/CH4 adsorption selectivities, and lower regeneration energy. This work demonstrates that simple ligand modification can be used to engineer the structures and tune gas adsorption properties of the resulting MOFs. [ABSTRACT FROM AUTHOR]

A novel fluorescent probe CuNI was synthesized and exhibited highly effective fluorescence detection ability for Cu2+ in aqueous solution (HOAc–NaOAc buffer, 10 mM, pH 5.0). CuNI was obtained by a simple condensation reaction between the aldehyde (MFNI, bearing the naphthalimide fluorescence group) and the 2-picolinyl hydrazide, which bears the Cu2+ recognized group. Under acidic conditions, CuNI showed turn-on fluorescence recognition of Cu2+ which could be readily distinguished with the naked eye under a 365 nm UV lamp and the detection limit is as low as 19.40 nM. It has been further demonstrated that CuNI was hydrolyzed under the action of Cu2+ and the significant increase of fluorescence is due to the obvious AIE effect of the hydrolysate MFNI. The application of the probe CuNI in imaging lysosomal Cu2+ in HepG2 cells has also been demonstrated. [ABSTRACT FROM AUTHOR]

By employing the strategy of positional isomerism, we designed and synthesized two unsymmetrical biphenyl tetracarboxylate ligands, and used them to successfully construct two novel copper-based MOFs. Structural determinations show that the resulting MOFs are three-dimensional networks, each incorporating two different kinds of discrete copper-carboxylate clusters, including the typical dicopper Cu2(COO)4(H2O)2 paddlewheel, as inorganic SBUs, and they display distinctly different topologies, highlighting the significant effect of ligand desymmetrization. ZJNU-9 is a neutral coordination network composed of one typical dicopper paddlewheel and a new dicopper cluster Cu2(COO)4(DMF)2(H2O)2 connected by the organic ligands, while ZJNU-10 is based on one typical dicopper paddlewheel and a new tetracopper cluster Cu4(COO)4(OH)2Cl(H2O)4 linked by the organic ligands to a cationic framework containing three types of cages. The two novel copper-containing clusters discovered in the two compounds greatly enrich the diversity and complexity of inorganic copper-carboxylate SBUs and thus MOF structures. Furthermore, a systematical investigation of their selective adsorption properties with respect to C2H2, CO2, and CH4 through pure-component isotherm measurements and IAST predictions revealed their promising potential for C2H2 recovery and CO2 removal from CH4 under ambient conditions. This work represents a rare example of homometallic pure-carboxylate hetero-SBU MOFs exhibiting highly selective adsorption of C2H2 and CO2 over CH4. [ABSTRACT FROM AUTHOR]

In this study, Co/Ni-MOF-74-derived CoNi2S4 nanoparticles embedded in porous carbon (CoNi2S4@C) were successfully prepared using Co/Ni-MOF-74 as precursor. According to the SEM and TEM images, the CoNi2S4 nanoparticles with a diameter of about 8 nm were uniformly distributed in the composite. Compared to the pure CoNi2S4, CoNi2S4@C exhibits excellent electrochemical performance as an anode material for sodium ion batteries (SIBs). After 50 cycles (at 100 mA g−1), the specific capacity of CoNi2S4@C could be maintained at 438 mA h g−1. After the CoNi2S4@C electrode was charged/discharged at different current densities of 50, 100, 200, 500, 800, 1000, and 2000 mA g−1, the specific capacity returned to the original level when the current density was restored to 50 mA g−1. This is due to the fact that the composite material can reduce the effect of volume expansion. [ABSTRACT FROM AUTHOR]

NbO-type MOFs built up from linear diisophthalate ligands and dicopper paddlewheel-based secondary building units offer an excellent platform to perform pore surface chemistry engineering and understand the structure–property relationship. In this work, we designed and synthesized two N-oxide functionalized linear diisophthalate ligands, and employed them to construct under suitable solvothermal conditions their corresponding NbO-type MOFs termed ZJNU-19 and ZJNU-20. Their gas adsorption properties with respect to C2H2, CO2, and CH4 were systematically measured, and adsorption selectivities of C2H2 and CO2 over CH4 were assayed using a well-known ideal adsorbed solution theory, establishing their promising potential for C2H2/CH4 and CO2/CH4 separations in connection with acetylene and natural gas separation and purification, which were found to be less dependent on the methyl position. In particular, at atmospheric pressure, the C2H2 and CO2 uptake capacities reach as high as 214.5 and 114.7 cm3 (STP) g−1 for ZJNU-19, and 210.0 and 111.9 cm3 (STP) g−1 for ZJNU-20 at 295 K, while the IAST-predicted C2H2/CH4 (v/v = 1/1) and CO2/CH4 (v/v = 1/1) adsorption selectivities are up to 42.2 and 6.4 for ZJNU-19, and 42.1 and 6.2 for ZJNU-20 at 298 K. Furthermore, a comparative investigation demonstrated that N-oxide is a powerful chemical functionality that can be utilized to design and construct porous framework compounds for boosting C2H2 and CO2 adsorptions. [ABSTRACT FROM AUTHOR]

To target a condensed version of the HKUST-1-like tbo-type MOF MFM-181, a new tetraisophthalate ligand, 3,6-dimethyl-1,2,4,5-tetra(5′-isophthalic acid)benzene, was rationally designed and synthesized based on ligand contraction and conformation preorganization strategy. Compared to its parent compound MFM-181, the resulting MOF ZJNU-10 features smaller cage sizes as well as higher density of open copper sites, thus endowing the material with the promising potential for C2H2/CH4 and CO2/CH4 separations associated with C2H2 purification and natural gas sweetening. At 298 K and atmospheric pressure, the uptake capacities of C2H2 and CO2 reach 151.5 and 108.3 cm3 (STP) g−1, while the IAST-predicted adsorption selectivities of C2H2 and CO2 over CH4 are up to 29.9 and 7.6, respectively. [ABSTRACT FROM AUTHOR]

The structure–property relationship investigation is of prime importance to development of porous MOFs exhibiting better performance. In this work, two regioisomeric diisophthalate ligands, with the only difference being the position of methyl and amino groups with respect to isophthalate moieties, were rationally designed and synthesized, and their corresponding dicopper paddlewheel-based MOFs were successfully fabricated under suitable solvothermal conditions. Single-crystal X-ray diffraction studies showed that they displayed the same network topology of ssa type, thus providing a platform to investigate the impact of the substituent's arrangement on gas adsorption properties. As revealed by gas adsorption studies, the pore textural properties and gas uptake capacities with respect to C2H2, CO2, and CH4 of ZJNU-11 are significantly higher than those of its isomer ZJNU-12 despite their same structures, indicating that the arrangement of functional groups makes a difference to the framework stabilities against desolvation and thus to the gas adsorption properties. In addition, ZJNU-11 is also capable of selectively adsorptive separation of C2H2 and CO2 from CH4, with high C2H2/CH4 (v/v, 1/1) and CO2/CH4 (v/v, 1/1) adsorption selectivities of 36.2 and 5.9 at 298 K and 1 atm. This work not only reported a porous MOF material for highly selective C2H2/CH4 and CO2/CH4 separations, but also demonstrated that the rational arrangement of substituent groups will be favorable to improve the MOF's stabilities and thus gas adsorption properties, which needs to be taken into account upon design and construction of porous MOFs. [ABSTRACT FROM AUTHOR]

Combining a linear diisophthalate ligand, 5,5′-(2,3-dimethylbenzene-1,4-diyl)diisophthalic acid, with CuCl2·2H2O under different solvothermal conditions afforded two distinct copper-based metal–organic frameworks (ZJNU-96 and ZJNU-97), which were structurally characterized by various techniques. Single-crystal X-ray diffraction analyses reveal that they contain the same inorganic and organic building units but exhibit different topological structures, thus belonging to supramolecular isomers. Furthermore, gas adsorption studies show that ZJNU-96 not only exhibits better stability against desolvation than ZJNU-97 but also displays promising potential for selective adsorptive separation of C2H2 and CO2 from CH4, with C2H2 (CO2) uptake of 183.6 (88.7) cm3 (STP) g−1 and C2H2 (CO2)/CH4 (v/v, 50/50) IAST adsorption selectivity of 26.6 (5.2) at 298 K and 1 atm. [ABSTRACT FROM AUTHOR]

Advanced materials are more convenient and safe for human use. In this case, a novel idea for the preparation of safer cables was proposed. A kind of self-healing conductive hydrogel (SHCH) was synthesized based on a dynamic Schiff base cross-linkage between the amine groups of chitosan and the benzaldehyde groups of aldehyde-modified PEG. Since there were many chemical cross-linking networks and conductive polypyrrole nanostructure in the hydrogel, it possessed bulk conductivity, mechanical and electrical self-healing properties. Because of the combination of the electrical conductivity and self-healing properties, the SHCH can be used as the conductor part of a cable. This cable can be directly powered off and restored easily at any time. [ABSTRACT FROM AUTHOR]

The metallosupramolecular Ti-based M4L4 cage of [Ti4O2L4Cl8] (L = 4-acetamidobenzoic acid) is synthesized via the one-pot solvothermal reaction of 4-aminobenzoic acid, acetic acid and TiCl4. The Ti(iv) ion functions as a Lewis acid catalyst for acylation condensation, and then coordinates with the resultant 4-acetamidobenzoic acid to afford Ti-based cage formation in a cascade fashion. [ABSTRACT FROM AUTHOR]

We present a gigantic polyoxozirconate nanocluster (Zr18O21(μ2-OH)2(OOCPh)28), involving 6, 7 and 8-coordinated Zr atoms. It exhibits visible light driven photocatalytic activity for H2 evolution. The current results could represent a prelude of polyoxozirconate-based photocatalysis. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanospheres with visible light photocatalytic activity were synthesized via a sol–gel approach using an amphiphilic diblock copolymer, polystyrene-block-polyacrylic acid (PS-b-PAA), as template at room temperature in toluene. The morphology and crystal structure of synthesized TiO2 nanospheres were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XRD pattern of TiO2 nanospheres revealed the crystal transformation, resulting in the change of photocatalytic activity. The XPS pattern revealed the formation of Ti–O–C bonds upon carbonization, as a result of visible light absorption. The TiO2 nanospheres had diameters ranging from 200 to 500 nm. The photodegradation experiments showed that such TiO2 nanospheres had pronounced visible-light photocatalytic activity. [ABSTRACT FROM AUTHOR]

By altering inorganic acid additives under otherwise identical synthetic conditions, two MOFs termed ZJNU-16 and ZJUN-17 were successfully constructed through solvothermal reactions of Co(NO3)2·6H2O and an amine-functionalized pyridinecarboxylate ligand, namely, 5-(3-aminopyridine-4-yl)isophthalic acid. Structural analyses indicated that the two compounds exhibited inorganic acid-guided structural diversities, adopting different SBUs, ligand conformations, and network topologies. ZJNU-16 is a (3,6)-connected network with a discrete trinuclear Co3-based cluster as an inorganic SBU, while ZJNU-17 is a (3,5)-connected framework featuring a nanotubular helical Co–carboxylate chain as an inorganic SBU. Furthermore, their gas adsorption properties towards N2, C2H2, CO2, and CH4 were systematically investigated, revealing the potential of ZJNU-17 for C2H2 separation and purification under ambient conditions. At 298 K and 106.7 kPa, the C2H2 and CO2 uptake capacities reach 100.9 and 63.8 cm3 (STP) g−1, and the IAST-predicted adsorption selectivities of C2H2 over CH4 and CO2 are 15.5 and 2.5, respectively. Although the performance is moderate compared to some reported MOFs, ZJNU-17 is a rare nanotubular helical chain-based MOF exhibiting selective gas separation potential. [ABSTRACT FROM AUTHOR]

Design and construction of stable adsorbents for efficient separation and purification of natural gas and C2H2 is fundamentally important in the chemical industry, and hierarchical cage-based MOFs are attractive in this regard due to their intrinsic structural advantages. In this work, a cage-based MOF (termed ZJNU-15) assembled from a tetranuclear Cu4O-based SBU and an amine-functionalized N,O-mixed donor ligand was solvothermally constructed. Single-crystal X-ray diffraction studies showed that the resulting MOF incorporates two different types of polyhedral cages in the entire network and bears incompatible open copper sites and uncoordinated amine groups immobilized in the pore surface. In view of its intriguing structural features, its gas adsorption properties with respect to C2 hydrocarbons, CO2, and CH4 were systematically investigated, revealing that it could achieve efficient removal of C2 hydrocarbons and CO2 from CH4 as well as separation of a binary C2H2–CO2 mixed gas, which is associated with natural gas and C2H2 separation and purification. At 298 K and 1 atm, for equimolar binary components, the IAST-predicted adsorption selectivities for C2 hydrocarbons over CH4 are above 17.7, while the CO2/CH4 and C2H2/CO2 adsorption selectivities are 5.0 and 4.4, respectively. Notably, stability studies showed that the framework maintained its structural integrity after being immersed in HCl/NaOH aqueous solutions within a pH range of 4–11 at ambient temperature for 24 h, indicating its good hydrolytic stability under harsh chemical conditions, which might lay a solid foundation for its practical applications. [ABSTRACT FROM AUTHOR]

Tailoring the structures and properties of metal–organic frameworks (MOFs) is very important for developing porous MOFs for targeted applications. Bent diisophthalate ligands offer a rich opportunity to construct MOFs with variable topologies because of their conformation flexibility and diversity. In this work, by employing a substituent-induced ligand conformation regulation strategy, we designed and synthesized three bent diisophthalate ligands bearing different substituents, and successfully constructed their corresponding dicopper paddlewheel-based MOFs under suitable solvothermal conditions. As revealed by single-crystal structural analyses, they feature distinct topological structures, depending on the attached substituents. Interestingly, the methoxy-functionalized MOF exhibits a novel topology, thus enriching the structural diversity of copper-bent diisophthalate frameworks. Furthermore, their gas adsorption properties with respect to C2H2, CO2, and CH4 were systematically investigated, revealing their promising potential for industrially important C2H2/CH4 and CO2/CH4 separations. More significantly, their separation performance can be greatly tailored by changing the substituents. Under ambient conditions, C2H2 and CO2 uptake capacities vary from 157.7 to 184.5 cm3 (STP) g−1, and 90.8 to 101.3 cm3 (STP) g−1, respectively, while C2H2/CH4 (50/50, v/v) and CO2/CH4 (50/50, v/v) adsorption selectivities range from 30.0 to 36.2, and 5.27 to 6.01, respectively. The amino-functionalized MOF performed better than the other two counterparts, which might be due to the synergistic effect arising from Lewis basic amino groups, higher density of open copper sites, and more suitable pore size. This work not only reported three MOFs for preferable adsorption of C2H2 and CO2 over CH4, but also demonstrated that the substituent-driven ligand conformation regulation is a facile way to modulate the structures and thus gas adsorption properties of MOFs. [ABSTRACT FROM AUTHOR]

The design and construction of porous materials for high-efficient adsorption-based separation of CH4 from C2H2 and CO2 is a fundamental goal in the chemical industry. In this work, a lactam-functionalized bent diisophthalate linker, 5,5′-(1-methylpyridin-2(1H)-one-3,5-diyl) diisophthalic acid, was judiciously designed and utilized to construct a dicopper paddlewheel-based MOF under solvothermal conditions. Single-crystal X-ray diffraction revealed that the resulting solid is a three-dimensional mfj-type network incorporating Lewis-acidic copper sites and accessible lactam groups as two different kinds of functional sites. Furthermore, gas adsorption studies indicated that the material exhibited great promise for C2H2/CH4 and CO2/CH4 separations. In particular, compared to the unmodified parent compound, the resultant MOF exhibits 9.4% and 12.9% higher C2H2 and CO2 uptake capacities and 48.0% and 28.3% higher C2H2/CH4 and CO2/CH4 adsorption selectivities for the equimolar gas mixtures at 298 K and 1 atm, despite the lower specific surface area and pore volume. This work reported the first lactam-functionalized MOF displaying significantly enhanced adsorption of CO2 and C2H2 over CH4. [ABSTRACT FROM AUTHOR]

The selective capture of C2H2 from C2H2–C2H4 and C2H2–CO2–CH4 mixtures is a very essential but highly challenging process during C2H4 and C2H2 purification in the chemical industry. In this work, by virtue of using oxygen-atom-rich C2H2 recognition sites, we, for the first time, designed and synthesized an N-oxide-functionalized tricarboxylate ligand and utilized it to successfully construct a copper-based MOF. N-Oxide functionalization exerted a significant effect on the ligand conformation, thus resulting in a new topological network that is different from that of the unoxidized parent compound. With a moderate surface area and the immobilization of N-oxide functionality and carboxylate oxygen atoms in two nanocages, the title MOF exhibited promising potential for the multifunctional separation of C2H2/C2H4 and C2H2/CO2/CH4 mixtures under ambient conditions, as shown by pure-composition isotherm measurements, IAST predictions, and molecular modeling studies. [ABSTRACT FROM AUTHOR]

Two new chromium and manganese bimetallic nanoclusters, [Cr8−xMnx(OH)8−x(H2O)x(OOCC6H5)16, x = 1.11] (1) and [Cr4Mn4O4(OOCC6H5)12·3CH3CN·H2O] (2), have been synthesized in a one-pot solvothermal reaction in this work. Under visible irradiation, cluster 1 can produce an increased photocurrent and exhibits significant visible-light-driven photocatalytic activity for H2 evolution in an aqueous system. Most importantly, it exhibits ultrahigh stability in both acid and base aqueous solutions, making it an excellent synthon for preparing functional materials. [ABSTRACT FROM AUTHOR]

We report a novel organo-iridium(iii) complex (Ir1) for the selective and sensitive determination of human serum albumin (HSA). The phosphorescence of Ir1 is turned-on by HSA in the urinary system. Importantly, Ir1 is much simpler and less time-consuming for HSA staining than Coomassie blue in proteomics studies. [ABSTRACT FROM AUTHOR]