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Fluorescence imaging can be employed in fields of medical treatment, astronomical exploration, and national defense security. Traditional fluorescence imaging often takes the single-photon techniques, which is vulnerable to background interference and photobleaching. Remedially, two-photon fluorescence imaging can achieve much higher-resolution fluorescence imaging for reducing scattering and deeper depth. Hence, by assembling the tetraphenylethylene backbones with nontoxic and non-noble K+ ions, compound 1 ([(Hdma)K(H2ettc)]n, H4ettc = 4′,4′″,4′″″,4′″″″(ethene-1,1,2,2-tetrayl)tetrakis(([1,1′-biphenyl]-4-carboxylic acid))) with the crystallization-induced emissions exhibited charming fluorescence imaging under two-photon excitation microscopy (TPEM). Besides, luminescent powders based on compound 1 can achieve high-resolution fingerprint recognition, providing secure access control and identification for a novel authentication method. Compared with the commercial fluorescent dyes coumarin-6, the as-synthesized compound 1 showed great solvent stability, indicating its durability against harsh environment. Moreover, compound 1 shows mechanoluminescent properties for the perturbation of weak supramolecular interactions within ordered arrangements of the H2ettc2− ligands. This novel compound has provided an important insight to the development of two-photon fluorescence imaging and advanced external-stimuli responsive materials. [ABSTRACT FROM AUTHOR]

CO direct esterification to dimethyl oxalate (DMO) has important industrial application value. Pd-based heterogeneous catalysts have been often utilized for this reaction. However, the effects of defect structures causing by the different morphologies of the support on the catalytic performance has not been investigated sufficiently. In this work, three different morphologies of CeO2 support (denoted as rod, cube, and octahedron) loading Pd were synthesized, and further investigated their catalytic activities for CO direct esterification to DMO. The Pd/CeO2-rod catalyst exhibited the best CO conversion compared with Pd/CeO2-cube and Pd/CeO2-octa. The results of Raman and XPS show that CeO2-rod has the highest oxygen vacancy concentration than those of CeO2-cube and CeO2-octa. In addition, it was found that partial interfacial electrons transfer from Pd to CeO2 support at the interface from the result of XPS. More intriguingly, the result of in situ DRIRS of CO exhibits that the partial interfacial electrons transfer from CeO2 to Pd, resulting from oxygen vacancies serve as a charge compensator to promote partial electrons transfer. The enriched electron of Pd would promote the adsorption and activation of CO, thus enhancing the catalytic activity. This work will provide a general understanding of the support effect to catalytic performance, which induced by the oxygen vacancies. [ABSTRACT FROM AUTHOR]

Pd-based heterogeneous nanocatalysts have wide application in chemical industry. However, the traditional synthesis process contains multi-steps such as impregnation, dry, calcination and reduction. The pre-synthesis nanoparticles process can reduce the steps, but need to remove the surfactants, which are added in the synthesis process. In this work, a facile one-pot hydrothermal synthesis process named as single molecular precursor method was successfully developed to prepare Pd/Mg(OH)2 heterogeneous nanocatalysts with clean surface. The as-synthesized Pd/Mg(OH)2 heterogeneous nanocatalysts show excellent performance for CO direct esterification to dimethyl oxalate (DMO). The WTY (weight time yield) of DMO can reach the high-performance of 2544 g kgcat.−1 h−1, while the conversion of CO is 62.6% and selectivity to DMO is 90.8%. The single molecular precursor method developed by this work can be extended to other supported noble metal nanocatalysts. [ABSTRACT FROM AUTHOR]

Extending photoresponse ranges of semiconductors to the entire ultraviolet–visible (UV)–shortwave near-infrared (SWIR) region (ca. 200–3000 nm) is highly desirable to reduce complexity and cost of photodetectors or to promote power conversion efficiency of solar cells. The observed up limit of photoresponse for organic-based semiconductors is about 1800 nm, far from covering the UV–SWIR region. Here we develop a cyanide-bridged layer-directed intercalation approach and obtain a series of two viologen-based 2D semiconductors with multispectral photoresponse. In these compounds, infinitely π-stacked redox-active N-methyl bipyridinium cations with near-planar structures are sandwiched by cyanide-bridged MnII–FeIII or ZnII–FeIII layers. Radical–π interactions among the infinitely π-stacked N-methyl bipyridinium components favor the extension of absorption range. Both semiconductors show light/thermo-induced color change with the formation of stable radicals. They have intrinsic photocurrent response in the range of at least 355–2400 nm, which exceeds all reported values for known single-component organic-based semiconductors. Developing new materials with broadband photoresponse is highly desirable for realizing commercial photodetectors with extended detection ranges. Here, the authors report a cyanide-bridged layer-directed intercalation approach to design viologen compounds with enhanced broadband photoresponse. [ABSTRACT FROM AUTHOR]

The title compounds were obtained from the reactions of copper or silver monohalides with the bidentate bis(diphenylphosphino)methane (dppm) ligand at room temperature in a mixed solvent. Single-crystal X-ray diffraction analyses indicate that both compounds crystallize in a monoclinic system but in different space groups. The structures are characterized by a trinuclear [M3I2(dppm)3]+ cation with a trigonal-bipyramid [M3( μ3-I)2] core. In agreement with the geometric characteristics of the M3 triangles, 31P NMR spectra exhibit a single peak for the [Cu3] cluster but a double-peak for the [Ag3] cluster. Preliminary optical studies by UV/Vis and emission techniques show major absorption shoulders at ∼286 nm for Cu3I2(dppm)3·I and ∼254 nm for Ag3I2(dppm)3·I, but no luminescence in the non-degassed MeCN solution at 298 K. The structures, bonding, electronic excitations and emissions are discussed based on relativistic density functional theory calculations. [ABSTRACT FROM AUTHOR]

The reactions of Ag2C2 and the corresponding silver perfluoro-dicarboxylates result in the formation of three new double and triple salts, Ag2C2·3AgO2CCF2CF2CO2Ag·7H2O ( 1), 2Ag2C2·6AgO2CCF2CF2CO2Ag·AgNO3·12H2O ( 2) and Ag2C2·4AgO2CCF2CF2CF2CO2Ag·17.5H2O ( 3), which have been structurally characterized by single crystal X-ray analysis. Their structures contain silver cages of various shapes: crown in 1, pentagonal bipyramid together with monocapped pentagonal bipyramid in 2, and square antiprism in 3, each containing an encapsulated acetylide dianion. Except for the pentagonal bipyramid, the other three silver cages are unprecedented. Compound 2 provides a unique example in which two kinds of silver polyhedra with different numbers of vertices (C2@Ag7 and C2@Ag8) co-exist in the crystal structure. [ABSTRACT FROM AUTHOR]

Silver nitrate reacts with sodium azide to give white powdery silver azide, which can be crystallized in aqueous ammonia. The compound belongs to orthorhombic space group Ibam with a = 5.600(1), b = 5.980(6), c = 5.998(1) Å, and Z = 4. The layer-type structure is constructed from edge-sharing regular rectangles, each composed of silver atoms at its vertices with an enclosed azide anion in a tilted orientation. The linear and asymmetrical structure of the azide anion in crystalline silver azide has been confirmed by its Raman spectrum. [ABSTRACT FROM AUTHOR]

Reduction of nitric acid reaction (2NO + HNO3 + 3CH3OH → 3CH3ONO + 2H2O) can convert by-product nitric acid into raw material methyl nitrite in the coal to ethylene glycol (CTEG) technology. This not only realizes the efficient recycling of nitrogen resources but also plays a crucial role in mitigating environmental pollution. Despite being a promising catalyst, the Pd/C catalyst face challenges due to its high metal loading, substantial loss rate, and consequent issues of poor stability, presenting obstacles in meeting industrial requirements. To address this issue, a defect strategy has been employed to develop a low-loaded 0.3% Pd/NC catalyst with robust metal-support interaction, resulting in a significant enhancement of catalyst stability. Remarkably, even after undergoing five cycles, the catalyst maintains a high nitric acid conversion rate of 90%. This improved performance can be attributed to the strong metal-support interaction driven by electron transfer from the nitrogen-doped carbon (NC) substrate to the Pd nanoparticles evident in the Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) results. This interaction effectively suppresses the leaching of the active Pd nanoparticles, leading to significantly enhanced stability and a noticeable reduction in the loss rate. Raman spectrum and electron paramagnetic resonance (EPR) results can further reveal that the increase in the defect density lead to the strong metal-support interaction after nitrogen doping (pyridinic-N-dominated). These findings highlight the significant potential of the Pd/NC catalyst and its applicability in expediting the industrialization process of catalyst.Graphical Abstract: Reduction of nitric acid reaction (2NO + HNO3 + 3CH3OH → 3CH3ONO + 2H2O) can convert by-product nitric acid into raw material methyl nitrite in the coal to ethylene glycol (CTEG) technology. This not only realizes the efficient recycling of nitrogen resources but also plays a crucial role in mitigating environmental pollution. Despite being a promising catalyst, the Pd/C catalyst face challenges due to its high metal loading, substantial loss rate, and consequent issues of poor stability, presenting obstacles in meeting industrial requirements. To address this issue, a defect strategy has been employed to develop a low-loaded 0.3% Pd/NC catalyst with robust metal-support interaction, resulting in a significant enhancement of catalyst stability. Remarkably, even after undergoing five cycles, the catalyst maintains a high nitric acid conversion rate of 90%. This improved performance can be attributed to the strong metal-support interaction driven by electron transfer from the nitrogen-doped carbon (NC) substrate to the Pd nanoparticles evident in the Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) results. This interaction effectively suppresses the leaching of the active Pd nanoparticles, leading to significantly enhanced stability and a noticeable reduction in the loss rate. Raman spectrum and electron paramagnetic resonance (EPR) results can further reveal that the increase in the defect density lead to the strong metal-support interaction after nitrogen doping (pyridinic-N-dominated). These findings highlight the significant potential of the Pd/NC catalyst and its applicability in expediting the industrialization process of catalyst. [ABSTRACT FROM AUTHOR]