A Coordination-Derived Cerium-Based Amorphous-Crystalline Heterostructure with High Electrocatalytic Oxygen Evolution Activity.

The rational design of heterogeneous catalysts is crucial for achieving optimal physicochemical properties and high electrochemical activity. However, the development of new amorphous-crystalline heterostructures is significantly more challenging than that of the existing crystalline-crystalline heterostructures. To overcome these issues, a coordination-assisted strategy that can help fabricate an amorphous NiO/crystalline NiCeOx (a-NiO/c-NiCeOx ) heterostructure is reported herein. The coordination geometry of the organic ligands plays a pivotal role in permitting the formation of coordination polymers with high Ni contents. This consequently provides an opportunity for enabling the supersaturation of Ni in the NiCeOx structure during annealing, leading to the endogenous spillover of Ni from the depths of NiCeOx to its surface. The resulting heterostructure, featuring strongly coupled amorphous NiO and crystalline NiCeOx , exhibits harmonious interactions in addition to low overpotentials and high catalytic stability in the oxygen evolution reaction (OER). Theoretical calculations prove that the amorphous-crystalline interfaces facilitate charge transfer, which plays a critical role in regulating the local electron density of the Ni sites, thereby promoting the adsorption of oxygen-based intermediates on the Ni sites and lowering the dissociation-related energy barriers. Overall, this study underscores the potential of coordinating different metal ions at the molecular level to advance amorphous-crystalline heterostructure design.

Construction of Highly Luminescent Lanthanide Coordination Polymers and Their Visualization for Luminescence Sensing.

NaH2SIP was selected as an organic ligand (NaH2SIP = 5-sulfoisophthalic acid monosodium salt). We successfully constructed a new class of lanthanide coordination polymers Ln-HS ([Ln(SIP)(DMF)(H2O)4]DMF·H2O; Ln = Eu, Tb, Sm, and Dy) by a simple solvothermal synthesis method. They exhibited excellent photoluminescence properties for Ln3+ ions, where Eu-HS and Tb-HS exhibited high quantum yields of 13.70 and 42.38%, respectively. The codoped lanthanide coordination polymers obtained by doping with different ratios of Eu3+/Tb3+ serve as excellent ratiometric thermometers with high sensitivities in the physiological temperature range, with values of 16.8, 7.0, and 14.5%·K-1, respectively. The luminescent colors of Tb0.95Eu0.05-HS and Tb0.94Eu0.06-HS exhibit variations from green to yellow to orange, achieving visualized luminescence in a narrow temperature range. The composite film material Tb0.94Eu0.06-HS@PMMA demonstrates this color variation. Next, Tb0.5Sm0.5-HS obtained by Tb3+/Sm3+ codoping was investigated. The difference in the luminescence colors visible to the naked eye at different excitation wavelengths and the change in luminescence colors occur in a very narrow temperature range. All of them show the great value of the visualized luminescence in practical anticounterfeiting, with double anticounterfeiting function and high security.

Facile synthesis of an ultrathin ZIF-67 layer on the surface of Sn/Ti co-doped hematite for efficient photoelectrochemical water oxidation.

Hematite is a promising photoanode for photoelectrochemical (PEC) water splitting but its practical performance has been severely hindered by its poor conductivity and sluggish water oxidation kinetics. Metal-organic frameworks (MOFs), considered as efficient oxygen evolution catalysts (OECs), have been widely applied for PEC water splitting in recent years. Here, we modified an ultrathin (about 2 nm) Co-based ZIF-67 layer on the surface of Sn/Ti co-doped α-Fe2O3 by a simple one-step solvothermal method. The resulting photoanode achieved a photocurrent density of 2 mA cm-2 at 1.23 VRHE, which was four-fold that of pristine Fe2O3. Detailed investigations manifest that Sn and Ti co-doping improves the conductivity of hematite, while ZIF-67 coating not only expands the optical-response range, but also accelerates the charge transfer at the semiconductor-electrolyte (S-E) interface to facilitate water oxidation kinetics. This work provides a method to design and study MOF overlayer decorating hematite photoanodes towards improving the PEC performance.

Two-dimensional heterostructures built from ultrathin CeO2 nanosheet surface-coordinated and confined metal-organic frameworks with enhanced stability and catalytic performance.

Two-dimensional (2D) metal-organic framework (MOF) based heterostructures will be greatly advantageous to enhance catalytic performance because they increase the contact surface and charge transfer. Herein, a novel 2D heterostructure named CeO2@NiFe-MOFs, in which monolayer NiFe-MOFs is coordinated with ceria (CeO2) to improve catalytic and stability performance, is successfully constructed by the strategy of in situ growth on the surface of ultrathin CeO2 nanosheets being functionalized with monolayer carboxylic acid groups. The 2D heterostructure possesses a sandwich structure, where monolayer NiFe-MOFs are coordinated to both the top and bottom surface of CeO2 nanosheets via joining carboxylic acid groups. In particular, CeO2 with robust coordination plays a significant role in the anchoring of carboxylic acid groups and binding strength of heterostructures. The 2D CeO2@NiFe-MOF heterostructure with a joint effect of metal-ligand coordination not only presents good structural stability but also significantly enhances the oxygen evolution reaction (OER) efficiencies in comparison to bare NiFe-MOFs, achieving a current density of 20 mA cm-2 at a low overpotential of 248 mV as well as durability for at least 40 h. Meanwhile, the electronics, optics, band gap energy and local strains of CeO2 decorated with 2D NiFe-MOFs are different to the properties of bare CeO2. Our study on the construction of an ultrathin CeO2 surface-coordinated and confined MOF layer may pave a new way for novel 2D MOF composites/heterostructures or multi-functional 2D CeO2 materials to be used in energy conversion or other fields.

Synthesis and optical and electronic properties of one-dimensional sulfoxonium-based hybrid metal halide (CH3)3SOPbI3.

We report the synthesis and optical and electronic properties of a one-dimensional sulfoxonium-based hybrid metal halide in an orthorhombic crystal system with a Pnma space group. To provide direct insights, a method is developed to calculate tolerance factors with the ionic radii of non-spherical cations from X-ray crystallographic data.

A new 3-D coordination polymer as a precursor for CuI-based thermoelectric composites.

Two complexes, [Cu6I6(L1)3]n (I) and [Cu4I4(L2)2]n (II) (L1 = 1,4-bis(phenylthio)but-2-yne; L2 = 1,4-bis(phenylthio)butane), as precursors for thermoelectric composites were prepared using a literature procedure. During the preparation of I, an unexpected 3-D polymorph [Cu4I4(L1)2]n (1) with a triclinic space group and an infinite [CuI]n staircase structure was obtained. This new polymorph (1) exhibited the same structure at both room temperature and 173 K. Complexes 1 and II were therefore pyrolysed to composites 2 and 3, respectively, at 400 °C under a nitrogen gas flow. Composite 3 was pale in color with a low carbon content (0.05 wt%) and easily disassembled during handling. By comparison, the high carbon containing (10.2 wt%) composite 2 can be compressed into a robust, light pellet (density 3.58 g cm-3), which showed a moderate to high Seebeck coefficient (543-1308 µV K-1) over the temperature range 70-240 °C.

A thermoelectric copper-iodide composite from the pyrolysis of a well-defined coordination polymer.

Coordination polymer 1 was prepared from CuI and a flexible [SNS] ligand L in acetonitrile. The thermal decomposition of 1 yielded a CuI-rich thermoelectric carbon composite 2, which is relatively light, thermally stable and robust. Composite 2 possesses high Seebeck coefficients (700-950 µV K-1) from rt to 204 °C after an optimization cycle.

Hydrogen-Bonding Interactions in Luminescent Quinoline-Triazoles with Dominant 1D Crystals.

Quinoline-triazoles 2-((4-(diethoxymethyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (1), 2-((4-(m-tolyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (2) and 2-((4-(p-tolyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (3) have been prepared with CuAAC click reactions and used as a model series to probe the relationship between lattice H-bonding interaction and crystal direction of growth. Crystals of 1-3 are 1D tape and prism shapes that correlate with their intermolecular and solvent 1D lattice H-bonding interactions. All compounds were thermally stable up to about 200 C and blue-green emissive in solution.

Electrostatic-Driven Exfoliation and Hybridization of 2D Nanomaterials.

Here, direct and effective electrostatic-driven exfoliation of tungsten trioxide (WO3 ) powder into atomically thin WO3 nanosheets is demonstrated for the first time. Experimental evidence together with theoretical simulations clearly reveal that the strong binding of bovine serum albumin (BSA) on the surface of WO3 via the protonation of NH2 groups in acidic conditions leads to the effective exfoliation of WO3 nanosheets under sonication. The exfoliated WO3 nanosheets have a greatly improved dispersity and stability due to surface-protective function of BSA, and exhibit a better performance and unique advantages in applications such as visible-light-driven photocatalysis, high-capacity adsorption, and fast electrochromics. Further, simultaneous exfoliation and hybridization of WO3 and MoS2 nanosheets are demonstrated to form hybrid WO3 /MoS2 nanosheets through respective electrostatic and hydrophobic interaction processes. In addition, this electrostatic-driven exfoliation strategy is applied to exfoliate ultrathin black-phosphorus nanosheets from its bulk to exhibit a greatly improved stability due to the surface protection by BSA. Overall, the work presented not only presents a facile and effective route to fabricate 2D materials but also brings more opportunities to exploit unusual exotic and synergistic properties in resulting hybrid 2D materials for novel applications.

Multicomponent (Ce, Cu, Ni) oxides with cage and core-shell structures: tunable fabrication and enhanced CO oxidation activity.

Solvothermal synthesis of Cu2O cubes from Cu(OAc)2 in ethanol provided templates for tunable formation of novel multicomponent composites: hollow CeO2-Cu2O (), core-shell NiO@Cu2O () and hollow CeO2-NiO-Cu2O (). Composites catalyze the oxidation of CO at a lower temperature than the parent Cu2O cubes.

High-Level Incorporation of Silver in Gold Nanoclusters: Fluorescence Redshift upon Interaction with Hydrogen Peroxide and Fluorescence Enhancement with Herbicide.

High-level incorporation of Ag in Au nanoclusters (NCs) is conveniently achieved by controlling the concentration of Ag(+) in the synthesis of bovine serum albumin (BSA)-protected Au NCs, and the resulting structure is determined to be bimetallic Ag28 Au10-BSA NCs through a series of characterizations including energy-dispersive X-ray spectroscopy, mass spectroscopy, and X-ray photoelectron spectroscopy, together with density functional theory simulations. Interestingly, the Ag28 Au10 NCs exhibit a significant fluorescence redshift rather than quenching upon interaction with hydrogen peroxide, providing a new approach to the detection of hydrogen peroxide through direct comparison of their fluorescence peaks. Furthermore, the Ag28 Au10 NCs are also used for the sensitive and selective detection of herbicide through fluorescence enhancement. The detection limit for herbicide (0.1 nm) is far below the health value established by the U.S. Environmental Protection Agency; such sensitive detection was not achieved by using AuAg NCs with low-level incorporation of Ag or by using the individual metal NCs.

Luminescent [Cu4I4] aggregates and [Cu3I3]-cyclic coordination polymers supported by quinolyl-triazoles.

Quinolyl-1,2,3-triazole ligand supported [Cu4I4] stair-step aggregates [Cu4I4(L1)2] (1), [Cu4I4(L2)2] (2), [Cu4I4(L3)2] (3), [Cu4I4(L4)2] (4), [Cu4I4(L5)2] (5), and six-membered [Cu3I3] metallacycle based coordination polymers [Cu2I2(L6)]n (6) and [Cu2I2(L7)]n (7) (ligands are 2-((1H-1,2,3-triazol-1-yl)methyl)quinoline (L1), 2-((4-alkyl-1H-1,2,3-triazol-1-yl)methyl)quinoline (propyl, butyl and isobutyl for L2, L3 and L4, respectively) and 2-(1-((quinolin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)alcohol (methanol, ethanol and propanol for L5, L6 and L7, respectively)) have been prepared and characterized by single-crystal X-ray diffraction (XRD), powder XRD, photoluminescence spectroscopy and thermogravimetric analysis. Complexes 1-5 are stair-step [Cu4I4] aggregate structures supported by two quinolyl-triazole hybrid ligands. Complexes 6 and 7 are rare cyclic [Cu3I3] aggregate-based 1-D coordination polymers. All ligands adopt a common tridentate-bridging coordination mode. These complexes are strongly luminescent with a yellow emission (500-700 nm) in the solid state.

Recent advances in C-S bond formation via C-H bond functionalization and decarboxylation.

The development of mild and general methods for C-S bond formation has received significant attention because the C-S bond is indispensable in many important biological and pharmaceutical compounds. Early examples for the synthesis of C-S bonds are generally limited to the condensation reaction between a metal thiolate and an organic halide. Recent chemical approaches for C-S bond formation, based upon direct C-H bond functionalization and decarboxylative reactions, not only provide new insights into the mechanistic understanding of C-S coupling reactions but also allow the synthesis of sulfur-containing compounds from more effective synthetic routes with high atom economy. This review intends to explore recent advances in C-S bond formation via C-H functionalization and decarboxylation, and the growing opportunities they present to the construction of complex chemical scaffolds for applications encompassing natural product synthesis, synthetic methodology development, and functional materials as well as nanotechnology.

Dianthraceno[a,e]pentalenes: synthesis, crystallographic structures and applications in organic field-effect transistors.

Two soluble and stable dianthraceno[a,e]pentalenes with two (DAP1) and six (DAP2) phenyl substituents were synthesized. Both compounds possess a small energy band gap and show amphoteric redox behaviour due to intramolecular donor-accepter interactions. X-ray crystallographic analysis revealed that DAP2 has a closely packed structure with multi-dimensional [C-H···π] interactions although there are no π-π interactions between the dianthraceno[a,e]pentalene cores. As a result, solution-processed field effect transistors based on DAP2 exhibited an average hole mobility of 0.65 cm(2) V(-1) s(-1). Under similar conditions, DAP1 showed an average field effect hole mobility of 0.001 cm(2) V(-1) s(-1).

A Triazolyl-Pyridine-Supported CuI Dimer: Tunable Luminescence and Fabrication of Composite Fibers.

The dinuclear complex [Cu2 I2 (L1)2 ] (1) (L1=3-((4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl)methyl)benzonitrile) is characterized by single-crystal X-ray diffraction (XRD), powder XRD, IR, photoluminescence spectroscopy, and thermogravimetric analysis. Unlike other related, known copper iodide complexes, it exhibits strong yellow emission in the solid state at both room temperature and 77 K. Showing good compatibility with PMMA, it is blended with the polymer in different weight ratios to prepare luminescent composite fibers.

A fluorescent light-up platform with "AIE + ESIPT" characteristics for multi-target detection both in solution and on paper strip.

We report a fluorescent light-up platform for multi-target detection in aqueous solution and on paper strip. The platform is based on a salicylaldazine fluorogen with aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) characteristics, which shows distinct advantages including ease of chemical modifications, free of self-quenching effect, excellent light-up ratio and large Stokes shift. To demonstrate the versatility of the platform, palladium cation and perborate anion, as well as UV light, were selected as the targets. The three representative probes, AIE-Pd, AIE-perborate and AIE-UV, light up specifically in the presence of the target both in aqueous solution and on paper strip. The immediate naked-eye response makes the probes ideal for instrument-free and power-free detection.

Destabilization of gold clusters for controlled nanosynthesis: from clusters to polyhedra.

A precisely controlled destabilization of gold thiolate clusters is demonstrated to grow 12 {110}-faceted gold dodecahedra with greatly enhanced catalytic capability, and reveal the growth mechanism by DFT simulations. This greatly advances our understanding of nanocrystal growth and opens a new window for controlling the dissociation of clusters to produce nanocrystals with specific shapes.

Carboxylate-rich hybrid ligands in Mn(II) complexes as precursors for water oxidation reactions.

A new family of Mn(II) complexes stabilized by carboxylate-rich hybrid ligands has been synthesized, characterized and applied as catalytic precursors for MnO2 nanoparticles in water oxidation by (NH4)2Ce(NO3)6.

Hybrid NS ligands supported Cu(I)/(II) complexes for azide-alkyne cycloaddition reactions.

Three copper complexes of nitrogen-sulfur donor ligands, [CuBr2(L1)] (1), [CuCl2(L2)2] (2) and [Cu2I2(L3)]n (3) (L1 = bis(2-cyclohexylsulfanylethyl)amine, L2 = 2-(benzylsulfanylmethyl)pyridine and L3 = 2-(4-pyridylsulfanylmethyl)pyridine), have been synthesized and characterized by single-crystal X-ray diffraction (XRD), powder XRD and TGA analysis. Complexes 1 and 2 are mononuclear Cu(II) complexes and are EPR active with distorted square-pyramidal and octahedral geometry, respectively. Complex 3 is a two-dimensional tetrahedral Cu(I) coordination polymer with 16- and 20-membered metallocycles. These complexes show good catalytic activities for one-pot azide-alkyne cycloaddition reactions in CH3OH-H2O.

"Click-and-click"--hybridised 1,2,3-triazoles supported Cu(I) coordination polymers for azide-alkyne cycloaddition.

Two novel pyridyl and thioether hybridised 1,2,3-triazole ligands 1-(2-picolyl)-4-(2-(methylthio)-pyridine)-1H-1,2,3-triazole (L1) and 1-(4-picolyl)-4-(2-(methylthio)-pyridine)-1H-1,2,3-triazole (L2) were prepared from CuAAC click reactions. Reactions of CuI with the ligands L1 and L2 yielded two one-dimensional coordination polymers [Cu6I6(L1)2]n (1) and [Cu2I2(L2)2]n (2). Single-crystal X-ray diffraction reveals that 1 and 2 are polymeric with [Cu6I6] and [Cu2I2] respectively as building blocks. Both ligands (L1 and L2) and complexes (1 and 2) are photoluminescence active. Complexes 1 and 2 are also catalytically active towards azide-alkyne cycloaddition reactions.