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Diketofurofuran derivatives show comparable singlet fission relevant excited state energies with diketopyrrolopyrrole analogues and tetracene.

Two luminescent 3D supramolecular structures [Cd3(L)2(2,2-bipy)2](DMF)3(CH3CH2OH)2(H2O) (1) and [Zn3(L)2(2,2-bipy)2(DMF)2](DMF)2(CH3CH2OH)2(H2O) (2) (H3L = 4,4′,4′′-nitrilotribenzoic acid) have been successfully synthesized under solvothermal conditions using Cd(NO3)2·4H2O or Zn(NO3)2·6H2O as the metal sources, and 4,4′,4′′-nitrilotribenzoic acid (H3L), 2,2-bipy as the ligands in DMF solvent. Compound 1 displays a bi-nodal (2,3,6)-coordinated net with {83}2{86·126·163}{8}6 topology, compound 2 can be described as a (3,6)-connected 2-nodal net with kgd topology. The phase purity of compound 1 and 2 is characterized by X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. Compound 1 and 2 can serve as effective luminescent sensors for Fe3+, Cu2+ and TNP via luminescent quenching.

In this work, a series of Ti(IV)/ZnIn2S4 composite photocatalysts were demonstrated by a facile two-step method. A Ti(IV) component was introduced into the flower-like ZnIn2S4 microspheres, which could act as an effective hole co-catalyst, shorten the charge migration distance, provide abundant active sites, inhibit the recombination of electron–hole pairs and mitigate the photocorrosion effect of ZnIn2S4. Benefiting from these favorable properties, the amorphous Ti(IV) modified ZnIn2S4 showed excellent H2 evolution performance which can reach 3685.2 μmol g−1 h−1, higher than that of pure ZnIn2S4 (2335.5 μmo g−1 h−1). Meanwhile, the modified ZnIn2S4 exhibits good stability after several consecutive hydrogen production runs. The photocatalytic purification of methyl orange (MO) in simulated wastewater was further tested. The degradation efficiencies, TOC removal, and highest hydrogen production were respectively 95%, 28.8% and 2650 μmol g−1 h−1. These results may provide an inspiration for tailoring multifunctional semiconductors with amorphous metal ions, which can be used as a photocatalytic H2 evolution catalyst with high-efficiency, as well as purifying the wastewater simultaneously.

Bismuth vanadate (BiVO4) has been widely used as a photocatalytic semiconductor for oxygen evolution in artificial photosynthesis. In this study, one-dimensional mesoporous BiVO4 nanofibers (BiVO4 NFs) were fabricated by the electrospinning strategy. The NFs were then deposited with NiCo layered double hydroxides (NiCo LDHs) to improve their reaction kinetics, charge transfers, and water oxidation activities. The obtained BiVO4/4 wt%NiCo LDHs composite exhibits enhanced photocatalytic oxygen oxidation activity that is approximately 1.6 times higher than that of BiVO4 NFs, due to the synergistic effects between BiVO4 NFs and NiCo LDHs, which can accelerate the transfer of holes between their surfaces. This design is a promising approach for fabricating large-scale nanofibers with good photocatalytic performance.

Hematite is recognized as an excellent photocatalyst for photoelectrochemical photoanodes for water oxidation because of its favorable band gap, excellent anti-photocorrosion and structural stability in alkaline solution. However, slow charge transport and fast carrier recombination in the bulk and at the hematite photoanode/electrolyte interface, have limited its applications for water splitting. Herein, we report a highly efficient hematite/ferrhydrite (Fh) core-shell photoanode system, consisting of hematite (α-Fe2O3) semiconductor nanorods which dramatically enhance light harvesting, and ferrhydrite as the hole-storage shell. Our integrated hematite/ferrhydrite core-shell photoanode shows 2.7 times increased photo-current density under simulated sun light irradiation.

In this work, a series of efficient visible-light-driven WO3/Cu (II) nanofiber photocatalysts, with superior photocatalytic activities for the degradation of dyes and aniline, were prepared by electrospinning and impregnation methods. The impregnation method brought about homogeneous distribution of Cu (II) species on the surface of WO3 nanofibers. The prepared WO3/Cu (II) nanofiber photocatalysts exhibited enhanced visible-light absorption and reduced charge recombination, as compared to pure WO3 nanofibers, due to the interfacial charge transfer (IFCT) effect between the Cu (II) species and WO3. The combined benefits of the grafting Cu (II) species on the surface of WO3, in terms of optical, surface, and texture properties, led to a significant improvement in the photocatalytic activity for the degradation of Rhodamine B (Rh B) and aniline under conditions of visible light irradiation. Upon the irradiation with visible light in the presence of WO3/Cu (II)-2% photocatalyst, the concentration of Rhodamine B (Rh B) decreased from 10 mg/L to 1.5 mg/L, and that of aniline solution decreased from 5 mg/L to 0.728 mg/L over a period of 3 h. And after running five cycles, the concentration of aniline solution could decrease from 5 mg/L to 0.89 mg/L by WO3/Cu (II)-2% photocatalyst.

A series of barbituric acid doped carbon nitride (CN-BA) photocatalysts were successfully prepared by copolymerizing dicyandiamide with barbituric acid (BA). Under AM1.5 simulated sunlight, CN-BA photocatalysts exhibit enhanced photocatalytic activity compared to pure carbon nitride for the degradation of aniline. The highest activity is obtained with 2% doped CN-BA photocatalyst. Results on the photodegradation of aniline indicate that for the optimized CN-BA photocatalyst, the concentration of aniline solution was reduced gradually from 16 mg/L to 1.354 mg/L in 2 h. This corresponds to a 6 times higher photodegradation efficiency than pure carbon nitride samples. The enhanced photocatalytic activity of CN-BA relies on the enhanced surface area, the higher light absorption and the reduced recombination of the photo-generated electron-hole pairs. This interpretation results from multiple characterizations with EPR, BET, N2 adsorption, Solid-state 13C NMR, UV–vis DRS, FESEM, and TEM. Under simulated sunlight irradiation, CN-BA is excited and generates electron-hole pairs. The photo-generated electrons in the CN-BA conduction band react with the molecular oxygen to form O2−. Part of the O2− transforms into OH, which further oxides aniline. Meanwhile, photo-generated holes in the valence band of CN-BA can benefit to the formation of OH or directly oxide aniline.

Carbon Nitride is considered as a promising photocatalyst material because of its unique properties such as environment-friendly, suitable band gap and high stability. However, the photocatalytic activity of pristine g-C3N4 was greatly hindered by the recombination of photo-generated electron-hole pairs. In this work, we provide an alternative method to address this problem by the construction of g-C3N4 isotype heterojunction (CNH−T/CNH−U) structure, which was successfully synthesized by a facile protonation assisted hydrothermal method. Under the irradiation of visible light (λ > 420 nm), the CNH−T/CNH−U isotype heterojunction photocatalyst displays much higher photodegradation activity of organic dyes degradation and H2-production activity than the pure CNH−T or CNH−U sample. This remarkably improved photocatalytic performance is attributed to the successful construction of CNH−T/CNH−U isotype heterojunction associated by protonation, which results in larger surface area and the more efficient separation of photo-generated electron-hole pairs, further investigated by electron paramagnetic resonance, photoluminescence, photocurrent measurement, and a series of active species trapping experiments.

In the current study, a mediator-free solid-state BiVO4/pyridine-doped g-C3N4 nano-Z-scheme photocatalytic system (BDCN) with superior visible-light absorption and optimized photocatalytic activity was constructed via an in situ hydrothermal method for the first time. The pyridine-doped g-C3N4 (DCN) nanosheets show strong absorbance in the visible-light region by pyridine doping, and the BiVO4 (∼10 nm) nanoparticles are successfully in situ grown on the surface of DCN nanosheets by the controlled hydrothermal method. Under the irradiation of visible light (λ > 420 nm), the BiVO4/DCN nanocomposite photocatalysts efficiently degrade phenol and methyl orange (MO) and display much higher photocatalytic activity than the individual DCN, bulk BiVO4, or the simple physical mixture of DCN and BiVO4. The greatly improved photocatalytic ability is attributed to the construction of the direct Z-scheme system in the BiVO4/DCN nanocomposite free from any mediator, which leads to enhanced separation of photogenerated electron–hole pairs, as confirmed by the photocurrent analysis. The possible Z-scheme mechanism of the BiVO4/DCN nanocomposite photocatalyst was investigated by transient time-resolved luminescence decay spectrum, active species trapping experiments, electron paramagnetic resonance (EPR) technology, and hydrogen evolution test.

Four ocotillol-type (20R)-protopanaxadiol metabolites, (20R,24S)-20,24-epoxy-12β,25-dihydroxdammaran-3-one (M3), and (20R,24R)-20,24-epoxy-12β,25-dihydroxydammarane-3-one (M4), (20R,24S)-20,24-epoxy-3β,25-dihydroxydammaran-12-one (M9) and (20R,24R)-20,24-epoxy-3β,25-dihydroxydammaran-12-one (M10) are synthesised from (20R)-protopanaxadiol. Their structures are confirmed by HRMS, 1H NMR and 13C NMR. Moreover, the absolute configurations of M3 and M4 are confirmed by the X-ray single crystal diffraction.

A large Ho 3+ :Li 3 Ba 2 La 3 (MoO 4 ) 8 crystal with high optical quality and well-developed appearance was grown by the flux method. The main spectral properties of the crystal, including the absorption spectra, fluorescence spectra and fluorescence decay curves were recorded at room temperature. The Judd-Ofelt (J-O) theory was applied to calculate the oscillator strength parameters Ω t ( t =2, 4, 6), spontaneous emission probabilities, fluorescence branching ratios, and radiative lifetimes of Ho 3+ ions undergoing transitions from ground state 5 I 8 to the excited states. The stimulated emission cross-section for the 5 I 7 → 5 I 8 transition was estimated to be 1.32×10 −20 cm 2 at 2045 nm by Fuchtbauer-Ladenburg (F-L) equation and the quantum efficiency of the 5 I 7 level was calculated to be 89%.

A photoelectrochemical (PEC) cell made of metal-free carbon nitride (g-C3N4) @siliconnanowire(Si NW) arrays (denoted as Si NWs/g-C3N4) is presented in this work. The as-prepared photoelectrodes with different mass contents of g-C3N4 have been synthesized via a metal-catalyzed electroless etching (MCEE), liquid atomic layer deposition (LALD) and annealing methods. The amount of g-C3N4 on the Si NW arrays can be controlled by tuning the concentration of the cyanamide solution used in the LALD procedure. The dense and vertically aligned Si NWs/g-C3N4 core/shell nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In comparison with FTO/g-C3N4 and Si NW samples, the Si NWs/g-C3N4 samples showed significantly enhanced photocurrents over the entire potential sweep range. Electrochemical impedance spectroscopy (EIS) was conducted to investigate the properties of the charge transfer process, and the results indicated that the enhanced PEC performance may be due to the increased photo-generated interfacial charge transfer between the Si NWs and g-C3N4. The photocurrent density reached 45 μA/cm2 under 100 mW/cm2 (AM 1.5 G) illumination at 0 V (vs. Pt) in neutral Na2SO4 solution (pH ∼ 7.62). Finally, a systematical PEC mechanism of the Si NWs/g-C3N4 was proposed.

Graphene nanoplatelets with excellent electrical conductivity in polymer matrices are highly promising for the industrial application of electrical conductive materials, however, poor dispersion results in high contents of graphene nanoplatelets being required for electrical property enhancement. In this study, graphene nanoplatelets (GNP)@polyaniline (PANI) nanocomposites were synthesized by in situ polymerization whereas the compatibility between GNP@PANI nanocomposites and the polymer matrix improved significantly due to graphene nanoplatelet encapsulation with polyaniline. GNP@PANI nanocomposites were utilized to prepare a permanent antistatic high-density polyethylene (HDPE) composite through solution blending and press forming in order for GNP@PANI nanocomposites to be dispersed homogeneously in the HDPE. The dispersion and compatibility of GNP@PANI nanocomposites in the HDPE were verified by morphology characterization, resulting in significant improvement of the electrical properties of the GNP@PANI/HDPE composites. It was observed that surface resistivity (ρs) and volume resistivity (ρv) decreased sharply with a 10 wt% GNP@PANI addition of nanocomposites. The results displayed that in situ polymerization and solution blending were effective methods for a conductive network establishment by addition of only 2 wt% of GNP and 8 wt% of PANI.

Cystosepiment-like cobalt nanoparticles@N-doped carbon composite named Co-NPs@NC with highly efficient electrocatalytic performance for oxygen evolution reaction was prepared from carbonization of N-doped Co-MOFs. The optimized Co-NPs@NC-600 shows overpotentials of 315 mV to afford a current density of 10 mA&middot, cm&minus, 2. Meanwhile, the electrocatalys presents excellent long-term durability. The outstanding electrocatalytic performance can be attributed to the unique cystosepiment-like architecture with high specific surface area (214 m2/g), high conductivity of N-doped carbon and well-distributed active sites.

Two C24 epimeric 3-acetylated ocotillol-type sapogenins, 20 R,24 S-epoxy-dammarane-3β,12β,25-triol acetate and 20 R,24 R-epoxy-dammarane-3β,12β,25-triol acetate have been achieved from 20( R)-protopanaxadiol. Their structures were confirmed by HRMS, 1H NMR, 13C NMR and single crystal X-ray diffraction which showed that their configurations were (20 R, 24 S) and (20 R, 24 R), respectively. In the crystal structure of the 24 ( S)-epimer, there were two intramolecular hydrogen bonds and a left-handed helical chain whilst in the 24 ( R)-epimer there was one intramolecular hydrogen bond and a right-handed helical chain.

A novel dinuclear Cu(II) coordination polymer, [Cu(BCPPO)H2O]n (1) [H2BCPPO = bis -4-carboxyphenyl phenyl phosphine oxide], has been synthesized and structurally characterized by single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, elemental analysis and infrared spectroscopy. As revealed by the single crystal X-ray diffraction, in complex 1, two paddle-wheel-type Cu2 units were connected by two BCPPO ligands to form one-dimensional infinite chain. The A3 coupling reaction of phenylacetylene, aldehyde and amine (piperidine) in the presence of the dinuclear Cu(II) coordination polymer as an efficient heterogeneous catalyst has also been studied. Complex 1 displayed high activity and afforded the corresponding propargylamines with moderate yields.

Addition polymerization usually results in polymers with long carbon-carbon main chains. Cyanoacrylate (CA) is arguably an important example of such polymerization and has gained widespread acceptance as an all-purpose adhesive. However, CA-based medical adhesives have never been approved by the U.S. Federal Drug Administration for use below the skin, mainly due to the low biodegradability and biocompatibility of their solid glue after polymerization. In this research, a cross-linking strategy involving the combination of alkyl-CA and the cross-linking agent poly(ethylene glycol)-di(cyanoacrylate) (CA-PEG-CA) to form a copolymeric network was used to synthesize a new generation of biodegradable CA medical adhesives. The degradability could be modulated by adjusting the ratio of CA-PEG-CA to alkyl-CA and the length of PEG. An optimal composite adhesive, LKJ11, was shown to have excellent biodegradability, adhesive capability, and biocompatibility. Importantly, the molecular weight of polycyanoacrylate chains in the polymerized LKJ11 was greatly reduced compared to those polymerized from pure butyl-CA. Thus, the degradation product could be readily extracted. The results showed that LKJ11 represents a new generation of CA-based biodegradable medical adhesives. This advance also provides a general strategy to facilitate the conversion of other polymers with long carbon-carbon main chains to a biodegradable form, thereby expanding the novel applications available for traditional polymeric materials.

Deltamethrin is used widely in Eriocheir sinensis aquaculture to remove wild fish and parasites. The residual deltamethrin greatly affects the growth and quality of E. sinensis. In this study, the LC50 of deltamethrin against E. sinensis at 24, 48 and 96 h was determined to be 6.5, 5.0 and 2.8 μg/L, respectively. The enzyme activity and gene transcription of SOD, CAT, and PO in the hepatopancreas of E. sinensis after deltamethrin stimulation showed an increasing tendency, and these enzymes reached their maximum activities at 6–10 d. The MDA content accumulated with increased time of deltamethrin stress. After 15 d of deltamethrin stress, the hepatopancreas of E. sinensis was found to be damaged based on HE staining. These results showed that deltamethrin is highly toxic to E. sinensis. But the half-life of deltamethrin is long and mainly relies on biodegradation. To resolve the pollution of residual deltamethrin, a strain of deltamethrin-degrading bacteria, P-2, was isolated from the sediment of an E. sinensis culture pond. Through morphological observation, physiological and biochemical identification and 16S rDNA sequence analysis, we found that this strain belonged to Paracoccus sp. When the pH was 7, the substrate concentration was low, the inoculation amount was high, and the deltamethrin degradation effect of Paracoccus sp. P-2 was good. The deltamethrin residue in the hepatopancreas and muscle of E. sinensis decreased significantly when Paracoccus sp. P-2 was added at 6.0 × 108 CFU/L. The degradation efficiency of Paracoccus sp. P-2 in the hepatopancreas and muscle was more than 70%. These results showed that Paracoccus sp. P-2, the first deltamethrin-degrading bacterium in aquaculture, could be used to remove residual deltamethrin and improve the food safety of E. sinensis.

Herein, we synthesized BiOBr/ultrathin g-C3N4/ternary heterostructures modified with black phosphorous quantum dots using a simple water bath heating and sonication method. The ternary heterostructure was then used for the photocatalytic degradation of tetracycline in visible light, with an efficiency as high as 92% after 3 h of irradiation. Thus, the photodegradation efficiency is greatly improved compared to that of ultrathin g-C3N4, BiOBr, and black phosphorous quantum dots alone. The synthesized ternary heterostructure improves the charge separation efficiency, thus increasing the photodegradation efficiency. This work provides a new and efficient method for the degradation of antibiotics in the environment.

We report the calculation of Er3+ Judd-Ofelt (JO) parameters for β-phase NaYF4:Yb3+, Er3+. The parameters were extracted from measured emission intensity ratios and the diffuse reflectance spectrum, augmented by a single radiative rate constant. The derived parameters were used to calculate the entire suite of radiative rate constants for the f–f transitions of Er3+ in the visible and near infrared (NIR) range and to calculate the absorbance spectrum. Two sets of JO parameter values, in units of pm2, were calculated using two available sets of reduced matrix elements (Ω2 2.36, Ω4 0.22, Ω6 1.24) and (Ω2 2.43, Ω4 0.21, Ω6 1.22).

Due to their tunable structure and porosity, metal–organic frameworks have provided a new platform for fluorescence sensing and adsorption/separation of gas or organic molecules. Many studies have focused on sensing metal ions, anions, or organic molecules through fluorescence quenching or enhancement of MOFs, but studies on pH-fluorescence sensors are seldom reported. Furthermore, highly solvent-dependent adsorption and degradation of dye molecules based on functional MOFs has not been explored to date. In this study, we describe a multifunctional Eu MOF, [H3O][Eu3(HBPTC)2(BPTC)(H2O)2]·4DMA (UPC-5, UPC = China University of Petroleum [East China]) based on a tetracarboxylate ligand. The luminescence intensity of UPC-5 is strongly correlated with the pH value in the pH range from 7.5 to 10.0, and a linear relationship between pH value and fluorescent intensity is observed. Another attractive property of UPC-5 is that its Li-exchanged form, Li-UPC-5, possesses solvent-dependent adsorption and degradation of rhodamine B. The highly efficient degradation or decolorization of rhodamine B with long-term stability and activity gives Li-UPC-5 a potential advantage in treating rhodamine B pollution.

A 2D wave-like layered framework based on benzotriazole-5-carboxylic acid (H2btca), 2,2′-bipy and zinc ions – [Zn(btca)(2,2′-bipy)]n (1) – has been resoundingly designed and synthesized by a solvothermal method. By changing the solvent from DMF to DMA, a 3D porous framework – [Zn2(btca)2(bpy)(H2O)]n·n(DMA) (2) – was obtained. Complexes 1 and 2 have been determined by single-crystal X-ray diffraction analysis and further characterized by powder X-ray diffraction (PXRD), elemental analysis, IR spectroscopy, and thermogravimetric (TG) analysis. Complex 1 shows an AA packing 2D layered structure and complex 2 displays a 3D open honeycomb framework with a (3,4)-connected 2-nodal fsc topology. Moreover, gas adsorption of 2a (the activated form of 2) and the luminescence properties of 1, 2 and 2a have also been investigated intensively.

A 3D porous framework ([Co1.5(tib)(dcpna)]·6H2O) (1) with a Wei topology has been synthesized by solvothermal reaction of 1,3,5-tris(1-imidazolyl)-benzene (tib), 5-(3′,5′-dicarboxylphenyl)nicotinic acid (H3dcpna) and cobalt nitrate. The electrocatalytic activity for water oxidation of 1 has been investigated in alkaline solution. Compound 1 exhibits good oxygen evolution reaction (OER) activities in alkaline solution, exhibiting 10 mA·cm−2 at η = 360 mV with a Tafel slope of 89 mV·dec−1. The high OER activity can be ascribe to 1D open channels along b axis of 1, which expose more activity sites and facilitate the electrolyte penetration.

Catalytic activities of neutral and charged palladium (Pd) nanoparticles are compared for hydrogen reduction half-reaction. In this work the sequential H2 dissociation from the surface of a Pd13H24...

Global warming and increased nutrient fluxes cause cyanobacterial blooms in freshwater ecosystems. These phenomena have increased the concern for human health and ecosystem services. The mass occurrences of toxic cyanobacteria strongly affect freshwater zooplankton communities, especially the unselective filter feeder Daphnia. However, the molecular mechanisms of cyanobacterial toxicity remain poorly understood. This study is the first to combine the established body growth rate (BGR), which is an indicator of life-history fitness, with differential peptide labeling (iTRAQ)-based proteomics in Daphnia magna influenced by microcystin-producing (MP) and microcystin-free (MF) Microcystis aeruginosa. A significant decrease in BGR was detected when D. magna was exposed to MP or MF M. aeruginosa. Conducting iTRAQ proteomic analyses, we successfully identified and quantified 211 proteins with significant changes in expression. A cluster of orthologous groups revealed that M. aeruginosa-affected differential proteins were strongly associated with lipid, carbohydrate, amino acid, and energy metabolism. These parameters could potentially explain the reduced fitness based on the cost of the substance metabolism.

Small organo-sulfur esters, which are common alkylating agents, are highly toxic compounds and have been proposed as possible chemical warfare agents. Previous studies have shown that dry, high Al content, X type zeolites have tetrahedral Al centers that exhibit nucleophilic properties that are of interest in chemical decontamination. This work examines the nucleophilic chemistry of representative small organo-sulfur esters with tetrahedral Al centers in NaX zeolite. Two sulfite esters and a sulfate and sulfonate ester were chosen as representatives. The chemistries of all representatives with the tetrahedral Al centers of NaX were found to be remarkably similar, namely the alkylation of the O atoms of the Al tetrahedra on the supercage surface of the zeolite to form a framework alkoxy species and the sodium salt of the acid of the corresponding organo-sulfur ester. Partial hydrolysis of the products was found, with the formation of the alcohol from the framework alkoxy specie and a Bronsted acid tetrahedral Al site in the zeolite. No hydrolysis of the anions of the salts was observed.

Due to the neurotoxicity of organophosphate (OP) pesticides and nerve agents synthesized as military or terror agents, their safe destruction and disposal is of considerable current importance. A representative OP, trimethyl phosphate (TMP), was adsorbed onto NaX zeolite, two mesoporous modifications, and a low-silica X zeolite. The nucleophilic chemical reactions of TMP with the zeolites were investigated by solid-state 13C and 31P nuclear magnetic resonance (NMR) and the solvent extracts by 1H, 13C, and 31P NMR. Nucleophilic substitution and subsequent hydrolysis reaction schemes are proposed. All of the zeolites have similar TMP decomposition yields, supporting the hypothesis that slow or incomplete diffusion of TMP in the microporous zeolite regions limits TMP decomposition.

Photoionization mass spectrometry reveals details of the multistep unimolecular mechanism, whereby the 2,2,6,6-tetramethyl-3,5-heptanedionato (thd−) anionic ligand decomposes, while still bound in the metal complex, to yield a gas-phase metal oxide product in metal−organic chemical vapor deposition (MOCVD) of lanthanide oxides from Ln(thd)3 precursors. The decomposition occurs with stepwise elimination of small closed-shell hydrocarbon fragments and carbon monoxide up to a penultimate Ln(OC2H) ethyneoxide, from which both LnO (dominant) and LnC2 (minor) products are derived. Formation of the metal oxide and carbide occurs in competition with a previously described mechanism(1-3) wherein sequential dissociation of ligand radicals produces the reduced metal Ln0. Evidence for gas-phase formation of a Ln2(thd)6 dimer as a result of expansion-cooling in the precursor source assembly is also given. Laser-assisted MOCVD of Eu(thd)3 on silica, with subsequent exposure to atmosphere, produces amorphous Eu2O3 with ...

The TiO2 gel doped with UO22+ and Eu3+ has been prepared by a sol-gel method. The quenching of the UO22+ emission by Eu3+ and the energy transfer from the excited state of UO22+ to the ground state oh Eu3+ have been investigated. The energy transfer has been studied by the measurement of luminescence lifetime tau, calculations of energy transfer efficiency eta(ET) and energy transfer rate W-ET The experimental results indicated that the quenching is combined static and dynamic mechanism, but the static mechanism is dominant.

A detailed photodissociation mechanism for the fluorinated lanthanide (Ln) β-diketonate metal−organic chemical-vapor deposition (MOCVD) precursors Ln(fod)3, Ln(hfac)3, and Ln(hfac)3diglyme was elucidated using photoionization time-of-flight mass spectrometry. The collisionless environment of the molecular beam source revealed a series of unimolecular steps, starting with dissociation of an intact β-diketonate ligand. Dissociation steps for the second and third ligands are associated with the attachment of a fluoride to the metal ion, leading to one of three ultimate products: Ln, LnF, or LnF2. Except in the case of Pr, no LnO is observed. The pattern of ligand fragmentation strongly supports a mechanism for the fluoride-attachment step which is similar to one previously proposed for the thermally activated decomposition of Ce(hfac)3glyme.(1) The detailed mechanistic understanding of the step-by-step fluorination will provide a basis for new ligand design, which maintains the advantageous mass-transport pr...

A heterogenized organo catalyst based on an organic–inorganic hybrid material was synthesized by covalently anchoring N-phenylthiazolium salts onto mesoporous silica MCM-41 materials. The results of powder X-ray diffraction and N2 adsorption show the persistence of the ordered two-dimensional hexagonal mesostructure of the functionalized materials. The integrity of the organic groups in the mesoporous materials is confirmed by solid-state 13C and 29Si CP-MAS–NMR spectroscopy. These hybrid mesoporous materials are efficient catalysts for the benzoin condensation and for the cross-coupling of aldehydes with acylimines to yield α-amido ketones. The catalytic activity of the heterogenized organo catalyst can further be enhanced by silylation of the residual Si–OH groups using Me3SiCl, due to an increased hydrophobicity of the support’s surface. The recyclability of the catalysts depends on the solvent of reaction: here aprotic and solvents of low polarity turned out to be beneficial.

A series of near-infrared (NIR) luminescent ternary lanthanide (Ln = Er, Nd, Yb) complexes covalently linked to xerogels by a chelate ligand 5-( N , N -bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline (phen-Si) were synthesized in situ via a sol–gel method. The obtained xerogel materials (named xerogel-bonded Ln complex) are rigid, and appear homogeneous confirmed by SEM images. Upon excitation at the maximum absorption wavelength of the ligands, all these xerogel materials with different lanthanide complex concentration show the characteristic NIR luminescence of the corresponding lanthanide ion, as a result of the efficient energy transfer from the ligands to the lanthanide ion. For the xerogel-bonded Er complex, the full width at half maximum (FWHM) of the 4 I 13/2 → 4 I 15/2 transition is 76 nm, which enables a wide gain bandwidth for the optical amplification. Based on the Judd–Ofelt theory, the radiative properties of the xerogel-bonded Nd complex (with Nd/Si molar ratio of 1/11 in the reaction) were studied.

We have fabricated and measured a series of electroluminescent devices with the structure of ITO/TPD/Eu(TTA)3phen (x):CBP/BCP/ALQ/LiF/Al, where x is the weight percentage of Eu(TTA)3phen (from 0% to 6%). At very low current density, carrier trapping is the dominant luminescent mechanism and the 4% doped device shows the highest electroluminescence (EL) efficiency among all these devices. With increasing current density, Forster energy transfer participates in EL process. At the current density of 10.0 and 80.0 mA/cm2, 2% and 3% doped devices show the highest EL efficiency, respectively. From analysis of the EL spectra and the EL efficiency–current density characteristics, we found that the EL efficiency is manipulated by Forster energy transfer efficiency at high current density. So we suggest that the dominant luminescent mechanism changes gradually from carrier trapping to Forster energy transfer with increasing current density. Moreover, the conversion of dominant EL mechanism was suspected to be partly responsible for the EL efficiency roll-off because of the lower EL quantum efficiency of Forster energy transfer compared with carrier trapping.

New near-infrared-luminescent mesoporous materials were prepared by linking ternary lanthanide (Er3+, Nd3+, Yb3+, Sm3+, Pr3+) complexes to the ordered mesoporous MCM-41 through a functionalized 1,10-phenanthroline (phen) group 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline. The resulting materials (denoted as Ln(hfth)(3)phen-M41 and Pr(tfnb)(3)phen-M41; Ln=Er, Yb, Nd, Sm; hfth = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dionate; tfnb = 4,4,4-trifluoro-1-(2-naphthyl)- 1, 3-butanedionate) were characterized by powder X-ray diffraction, N-2 adsorption/desorption, and elemental analysis. Luminescence spectra of these lanthanide-complex functionalized materials were recorded, and the luminescence decay times were measured. Upon excitation at the absorption of the organic ligands, all these materials show the characteristic NIR luminescence of the corresponding lanthanide (Er3+, Nd3+, Yb3+, Sm3+, Pr3+) ions by sensitization from the organic ligands moiety. The good luminescent performances enable these NIR-luminescent mesoporous materials to have possible applications in optical amplification (operating at 1300 or 1500 nm), laser systems, or medical diagnostics. (C) 2006 Elsevier Inc. All rights reserved.

The dependence of the performance of organic light-emitting devices(OLEDs) on the sheet resistance of indium-tin-oxide(ITO) anodes was investigated by measuring the steady state current density brightness voltage characteristics and the electroluminescent spectra. The device with a higher sheet resistance anode shows a lower current density, a lower brightness level, and a higher operation voltage. The electroluminescence(EL) efficiencies of the devices with the same structure but different ITO anodes show more complicated differences. Furthermore, the shift of the light-emitting zone toward the anode was found when an anode with a higher sheet resistance was used. These performance differences are discussed and attributed to the reduction of hole injection and the increase in voltage drop over ITO anode with the increase in sheet resistance.

A layered luminescent mesostructured thin film of silica–CTAB–Tb(acac) 3 composite has been synthesized by a dip-coating process through an in situ sol–gel method. The terbium (Tb 3+ ) ion and β-diketone organic ligand acetylacetone (acac) were introduced into the precursor solution, respectively. The as-synthesized composite film was transparent, colorless and possessed a layered structure. After the composite film was dried at 50 °C for a few minutes Tb(acac) 3 complex was synthesized in the mesostructured thin film, which can be indicated by the luminescence of the composite film under the UV lamp. The properties of the samples were characterized by XRD, absorption, Fourier transform infrared spectroscopy, and luminescent spectra.

We report the first demonstration of a high-efficiency photoelectrochemical (PEC) water splitting reaction using a novel Si NWs/WO3 core/shell photoanode prepared by a mild and inexpensive metal-catalyzed electroless etching process followed by dip-coating, airing and annealing methods. The dense and vertically aligned Si NWs/WO3 core/shell nanostructure were characterized by scanning electron microscopy, transmission electron microscopy and x-ray diffraction. In comparison to planar n-Si, Si NWs and planar Si/WO3, the Si NWs/WO3 samples showed significantly enhanced photocurrent over the entire potential sweep range. More significantly, the Si NWs/WO3 samples have an exceptionally low photocurrent onset potential of -0.6393 V versus reversible hydrogen electrode (RHE), indicating very efficient charge separation and charge transportation processes. The as-prepared electrode also has a photocurrent density of 2.7 mA cm-2 at 0.6107 V versus RHE in 0.5 M Na2SO4 solution under simulated solar light irradiation (100 mW cm-2 from 300 W Xenon lamp coupled with an AM 1.5 G filter). An optimal solar-to-hydrogen efficiency of about 1.9% was achieved at 0.2676 V versus RHE. Electrochemical impedance spectroscopy was conducted to investigate the properties of the charge transfer process, and the results indicated that the enhanced PEC performance may due to the increased charge separation. The x-ray photoelectron spectroscopy measurements indicated the chemical composition of the Si NWs/WO3 nanostructure. Our work has provided an efficient strategy to improve the energy conversion efficiency and photocurrent of water splitting materials.

Graphene nanoplatelets coated by polyaniline (GNP@PANI) and ethylene–vinyl acetate (EVA) copolymer–high-density polyethylene (HDPE) were used for the first time to prepare high-performance antistatic composites through an effective method that combined solution mixing and melt blending. GNP@PANI nanocomposites were fabricated by in situ polymerization to improve the dispersion of graphene nanoplatelets (GNPs) in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix. The GNP@PANI nanocomposites and EVA were first prepared as a premix through solution mixing, and then, the premix and HDPE were prepared as highly antistatic composites through melt blending. The dispersion of the GNPs in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix were confirmed by field emission scanning electron microscopy and transmission electron microscopy observations. The GNP@PANI–EVA–HDPE composites met the requirements for antistatic materials when the content of the GNP@PANI nanocomposites was 5 wt % with only about 1 wt % GNPs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45303.

Eu3+-activated calcium silicate (CaO–SiO2∶Eu3+) luminescent films were prepared by the sol–gel method. The structural evolution of the film was studied by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the luminescence properties of the phosphor films were investigated as a function of heat treatment temperature. The XRD study indicates that a kilchoanite phase forms in the film sintered at 800 °C, which is different from that in gel powder treated under the same conditions. The SEM results show that the film thickness decreases and the particles in the film become smaller with increasing heat treatment temperature. The CaO–SiO2∶Eu film shows the characteristic emission of Eu3+ under UV excitation, with the Eu3+5D0 → 7F2 band (616 nm) being the most prominent. A large difference in the Eu3+ lifetime is observed between the film samples treated at 500 and 700 °C (or above). Concentration quenching occurs when the Eu3+ doping concentration is above 6 mol% of Ca2+ in the film.

By comparing the phosphorescence spectra of Gd(acac)3 (acac = acetylacetone), Gd(TFacac)3 (TFacac = 1,1,1-trifluoroacetylacetone), the effects of fluorine replacement of hydrogen on the triplet state energy of the ligands were revealed. Fluorine can lower the triplet state energy of Hacac and make it more suitable for energy transfer towards the 5D4 state of terbium. Organic electroluminescent devices (OELDs) with the corresponding trivalent terbium complexes as emissive layers were fabricated. Triple-layer-type devices with a structure of glass substrate/ITO (indium tin oxide)/PVK [poly(N-vinylcarbazole)]/PVK∶Tb complex: PBD [2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole]/PBD/Al exhibit bright green luminescence upon applying a dc voltage. The luminance of a device with Tb(TFacac)3phen (1,10-phenanthroline) and Tb(TFacac)3 as emissive layer is higher than that of the corresponding devices with Tb(acac)3(phen) and Tb(acac)3 as emissive layers. The EL device with Tb(TFacac)3(phen) as emitter exhibits characteristic emission of Tb3+ ions with a maximum luminance of 58 cd m−2 at 25 V.

Ternary europium complexes with thenoyltrifluoroacetone (TTA) and phenanthroline (phen) were incorporated into SiO2/polymer matrix by a sol-gel method. The gels exhibit the characteristic emission bands of europium ion. In addition, Eu3+ presents a longer fluorescence lifetime in gel than in the corresponding pure complex powder. Concentration effects on the luminescence intensity were investigated. The reasons that are responsible for above results are also discussed in the context.

A luminescent europium-organic framework with tubular channels based on the H4BTMIPA ligand (H4BTMIPA = 5,5'-methylenebis(2,4,6-trimethylisophthalic acid)) was assembled and characterized. The [H2N(CH3)2](+) ions as counterions are located in the channels. The cation exchange between [H2N(CH3)2](+) and metal ions resulted in complex that can selectively sense Fe(3+) and Al(3+) ions through fluorescence quenching and enhancement, respectively.

The title compound, (C(8)H(15)N(2))[LaCl(4)(CH(3)OH)(C(3)H(7)OH)], consists of one 1-butyl-3-methyl-imidazolium (BMI(+)) cation and one hexa-hedral tetra-chlorido(methanol)(propan-2-ol)lanthanate anion. The La(III) ion is eight-coordinate, with the La(III) ion bridged by a pair of Cl atoms, so forming chains propagating along the a-axis direction. Each La(III) ion is further coordinated by two isolated Cl atoms, one methanol and one propan-2-ol mol-ecule. The coordinated methanol and propan-2-ol mol-ecules of the anion form O-H⋯Cl hydrogen bonds with the Cl atoms of inversion-related anions. The BMI(+) cation froms C-H⋯Cl hydrogen bonds with the Cl atoms of the anion. The anions are located in the C faces of the triclinic unit cell, with an inversion center in the middle of the La(2)Cl(2) ring of the polymeric chain.

A luminescent film with terbium-complex-bridged polysilsesquioxanes has been prepared by sol-gel processing of a new bifunctional monomer that combines the role of a sol-gel molecular precursor with a Tb3+ ion coordinate donor. The emission from Tb3+ ion due to ligand-to-metal energy transfer was observed by UV excitation.

Retraction of articles., This article reports the retraction of articles published in Acta Crystallographica Section E between 2005 and 2009.

In the centrosymmetric dimeric title compound, [Pr2(C5H9O2)2(C11H19O2)4(CH3OH)2], the two praseodymium(III) atoms are eight-coordinate and are bridged by O atoms from the two pivalate anions. Each PrIII ion is further coordinated by two chelating 2,2,6,6-tetra­methyl-3,5-hepta­nedionate (thd−) ligands and one methanol mol­ecule. The distance between the two PrIII ions is 4.273 (5) A. Intra­molecular hydrogen bonds exists between the methanol hy­droxy group on one PrIII atom and a chelating O atom of a thd− ligand coordinated to the symmetry-related PrIII atom.

Two porous metal–organic frameworks (1 and 2) with a fsc topology based on mixed ligands have been assembled and characterized. The different pillared ligands (pyrazine for 1 and 4,4′-bipyridine for 2) significantly influence the pore size of the frameworks. Gas uptake measurements reveal that complex 1 possesses higher H2, CO2, and CH4 uptake capacities than 2, although the surface area of 1 is lower than that of complex 2. These results further experimentally prove that the pore size plays an important role in gas uptake in porous MOFs, and the slit pore with a size of ~6 Å exhibits stronger interactions with gas molecules.

In the asymmetric unit of the title compound, [Mn(C2O4)(C3H10N2)2]Cl·H2O, there are two independent MnIII complexes, two Cl− anions and two uncoordinated water molecules. Each MnIII atom is hexacoordinated by four N atoms from two propane-1,3-diamine ligands and two O atoms from one oxalate ligand, resulting in a slightly distorted octahedral MnO2N4 geometry. Mn—O and Mn—N bond lengths are in the ranges 1.969 (2)–2.020 (3) and 2.068 (3)–2.113 (4) Å, respectively. There are weak intermolecular O—H...O, O—H...Cl, N—H...O and N—H...Cl hydrogen bonds with D...A distances in the range 2.831 (4)–3.423 (3) Å.

Solvothermal reactions of 5-hydroxyisophthalic acid (hip) and different N-containing auxiliary ligands with transition metal salts provided four new metal–organic coordination polymers (MOPs), namely, {Zn(hip)(2,2′-bipy)·2H2O}n (1), {[Ni(hip)(4,4′-bipy)(H2O)]·DMF·2H2O}n (2), {Zn(hip)(tib)·2H2O}n (3), {[Zn2(hip)2]·5H2O}n (4), (2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine, DMF = N,N′-dimethylformamide, tib = 1,3,5-tris(1-imidazolyl)benzene). All of the complexes have been structurally characterized by single-crystal X-ray diffraction analyses, infrared spectra (IR), elemental analyses and powder X-ray diffraction (PXRD). Single crystal X-ray diffraction analysis reveals that complex 1 exhibits a one-dimensional zig-zag chain, in which strong π⋯π interactions are found between neighbouring 2,2′-bipy molecules. Complex 2 has a 2D double-layer square framework, exhibiting AA stacking sequence, and the topology of each layer is typical 2D (44)-sql. In complex 3, both hip and tripodal ligand tib act as bidentate bridging ligand and extend the tetragonal pyramid Zn(II) centers to a 2D wavy framework, exhibiting an AB stacking sequence. The 2D layer structures in 2 and 3 are different from each other. In complex 4, the oxygen atoms of the hydroxy group of hip participate in constructing a framework, which results to the 3D net framework with 1D channel. The structural and topological differences of the four MOPs indicate that the auxiliary ligand play important roles in the formation of final structures. Furthermore, the thermal stability and photoluminescence properties of complexes 1–4 were investigated.