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The influences of conjugation on the third-order nonlinear optical (NLO) properties of covalent organic frameworks (COFs) provide guidelines to design the structures for desired applications.

By intercalating KOH into multilayered Ti3C2Tx, an efficient adsorbent with coordination/cation exchangeable sites is developed for Tl+ removal. The –OH sites can coordinate Tl+ while the exchange of K+/Tl+ contributes selective and fast adsorption.

TPE-CoPor-COF shows high FECO (91–95%) in the range of −0.6 to −1.0 V, and a maximum jCO of −30.4 mA cm−2 at −1.0 V, exceeding most of reported COF-based electrocatalysts.

Black phosphorus (BP) is an emerging two-dimensional semiconductor material, which has interesting structural features and broad application prospects in the fields of optoelectronic devices, energy storage, and biomedicine. However, a large amount of evidence is still needed to clarify the potential mechanism for the synthesis of high-quality BP crystals in chemical vapor transport (CVT) reactions. In this work, High-purity BP crystal was synthesized by CVT method in amorphous Red Phosphorus (aRP), Sn and I2 system. We found that the synthesis of BP experienced three stages of structural transformation of aRP-P4-Hittorf’s Phosphorus (HP)-BP. First, the phase transition of aRP and P4 molecules was reversible in the sublimation stage; then, the P4 molecules were gradually transformed into the HP structure in the transportation and deposition stage; however, the nucleation of BP quickly inhibited the growth of HP and completed the phase transition quickly; Finally, the remaining P4 molecules were transformed into BP structure, which promoted the growth of BP crystals. This crystallization kinetics explained the nucleation mechanism during the formation of BP, and the competitive nucleation between HP and BP provided the possibility for the bottom-up preparation of BP nanobelts.

Recent developments in ferroic phase transition molecular crystals (ferroelectrics, ferroelastics, and multiferroics) are highlighted.

The as-prepared TPPDA-CoPor-COF shows high CO faradic efficiencies of 87–90% from −0.6 to −0.9 V vs. RHE, and the largest CO partial current density of TPPDA-CoPor-COF exceeds most of reported COF-based electrocatalysts.

3D lead iodide perovskite analogs display both high stability and quasi-isotropic photoresponse, consistent with both 3D crystallographic and electronic structures.

The two-dimensional black phosphorus can interact with metal compounds to form BP–M composites, showing tailored properties. This review summarizes BP–Ms in different applications, revealing the challenges and prospects of this composite material.

Upcycling the electroplating sludge (EPS) and PET waste into metal–organic-frameworks (MOFs) is beneficial for both pollution mitigation and sustainable economy. Herein, we report a green synthesis of Ni-MOF nanocrystals by simultaneously using EPS and PET waste as precursors without any precedent. In particular, when EPS was fully utilized, with numerous Fe3+/Cu2+ ions coexisting with Ni2+ ions, the desired Ni-MOFs could still be successfully fabricated. The Ni-MOF nanocatalysts exhibited an excellent activity towards the photoreduction of CO2, giving 9.68 × 103 μmol h−1 g−1 of CO with 96.7% selectivity over H2 evolution. Additionally, the apparent quantum yield at 420 nm is 1.36%, which is superior to that of most catalysts in similar systems. This study clearly suggests that the MOF nanocrystals with excellent photocatalytic performances could be successfully fabricated from solid wastes.

The photoreduction of diluted CO2 into value-added solar fuel is a discipline at the forefront of energy and environmental research. However, this exploration largely suffers from unsatisfactory activity and selectivity. Herein, lattice-strained nickel hydroxide nanosheets (NSs) were successfully constructed via a vanadium-doped strategy toward the photoreduction of diluted CO2. X-ray absorption fine structure spectroscopy and Williamson–Hall analysis based on X-ray diffraction revealed the formation of lattice strain on the surface of the Ni(OH)2 NSs. Consequently, the lattice-strained sample exhibited the highest CO production yield of 20.7 μmol with a CO selectivity of 97% after 3 h in pure CO2, which were almost 4 and 1.3 times those of its parent Ni(OH)2 NS. Even in diluted CO2 (0.1 atm), it exhibited a CO production rate of 5.8 μmol h−1 with a CO selectivity of 91.3%, surpassing most previous works in pure CO2. Further characterizations revealed that the lattice strain could greatly improve the CO2 adsorption and activation, and the separation efficiency of the photogenerated carriers, thus leading to an enhancement in the carbon dioxide reduction activity. This work discloses a clear atomic-level correlation between lattice strain and diluted CO2 photoreduction, which lays a foundation for reinventing their applications in photocatalysis, among other applications.

Single-element phosphorus has received extensive attention in recent years because of its remarkable photocatalytic properties. In the present experiment, amorphous red phosphorus was controllably transformed into [P12(4)]P2[and Hittorf's phosphorus structures by performing bismuth catalysis. The temperature-controllable chemical vapor transport reaction realized the conversion of more than 90% of amorphous red phosphorus to single-phase crystalline red phosphorus. Under very mild ultrasonic treatment, the high-quality [P12(4)]P2[microbelts and Hittorf's phosphorus microrods were stripped into a few layers of nanobelts and sheet-like structures, respectively. As non-metallic catalysts, their rapid photocatalytic degradations of pollutants (methyl orange) and high hydrogen evolution rates revealed the rapid charge transfer and application potential of the crystalline red phosphorus catalyst. The results of this work could provide new ideas for the development of phosphorus-based crystalline photocatalytic systems.

WC–Al2O3 composites possess higher corrosion resistance compared with WC–Co cemented carbide. The main corrosion mechanism for WC–Al2O3 composites is the oxidation of the WC phase.

As an advanced two-dimensional (2D) material with unique properties, black phosphorus (BP) has attracted great attention in a variety of fields. One of the main obstacles for the practical application of BP is the poor ambient stability of few-layer BP, especially under light irradiation. In this study, a light-absorbing conjugated polymer is functionalized on the surface of BP during the exfoliation process, yielding BP nanosheets with light-resistance. The obtained BP/polymer nanosheets demonstrate enhanced stability compared to pure BP under sunlight. Systematic characterization reveals that the crystal structure and electronic characteristics of BP are well retained after 30 days of sun exposure. This convenient and efficient conjugated polymer passivation provides a novel light-prohibited method to improve the stability of BP for future applications.

Host–guest molecular crystals are classical types of molecular materials widely applied for fluorescent sensors, absorption, separation, etc. Their significance lies in deciphering the intermolecular interactions in crystal engineering and expanding the scope of pharmaceuticals and chemical-responsive smart materials. Here, we report three flexible host–guest molecular solvate crystals, 1·CH2Cl2, 1·dioxane, and 1·DMF, that crystallize with a much lower boiling point guest dichloromethane (DCM, 313 K), and high boiling points guest dioxane (374 K) and dimethylformamide (DMF, 426 K). Surprisingly, thermogravimetric and crystallographic characterizations show that 1·CH2Cl2 has a relatively high desolvation onset temperature of 390 K, which is much higher than that of 1·dioxane (305 K) and 1·DMF (307 K). Crystal structure analysis shows that this high stability originates from the confinement and steric effects of the trapped guest solvent molecules in the crystal cavities. Powder X-ray diffraction shows that the three compounds' desolvated powder can self-trap the CH2Cl2 (DCM) molecules, returning to the 1·CH2Cl2 state. Moreover, spectroscopic characterization presents an emission redshift of about 30 nm for 1·dioxane and 1·DMF compared to that of the former. These results are attributed to the flexible host plate's dihedral angle that undergoes a drastic change of about 50° which leads to the greatly enhanced conjugation degree of the host plate.

Functional dynamic molecular crystals have drawn increasing interest in exploring next-generation flexible and smart materials. Molecular rotors, as a typical type of dynamic material, are good candidates that can exhibit bulk properties and functionalities. Herein, we report a molecular rotor crystal as a model system to show a unique structural phase transition-related ferroelasticity. The molecular rotor is dumbbell shaped containing a freely rotating axial rotator and multiple peripheral tert-butyl groups on the two plates with restricted motions. The crystal undergoes a ferroelastic structural phase transition at 263 K with unconventional inverse temperature symmetry breaking (ITSB), i.e., a higher-symmetric low-temperature paraelectric phase (point group mmm) vs. a lower-symmetric high-temperature ferroelastic phase (point group 2/m). Combined crystallographic and NMR spectroscopy studies reveal that unequal motions of the peripheral tert-butyl rotators and anisotropic steric repulsion among the molecules are the key cooperative intermolecular interactions to drive a concerted molecular movement to result in the unique ferroelastic phase transition with ITSB. Our study may open avenues for designing and exploring new types of dynamic functional materials.

Glioma is an aggressive brain cancer with poor prognosis and high invasiveness. Dysregulation of circular RNAs (circRNAs) has been widely discovered in various cancers, including glioma. However, the molecular mechanism of circ_0034642 in glioma is still unclear. The expression of circ_0034642, microRNA (miR)-625-5p and transgelin-2 (TAGLN2) in glioma tumors and cells was detected by performing a quantitative real-time polymerase chain reaction (qRT-PCR). The stability of circ_0034642 was determined by carrying out RNase R treatment. Cell proliferation was evaluated by performing the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Glycolysis was analyzed by measuring the extracellular acidification rate (ECAR) using glucose detection and lactic acid detection kits. Cell migration and invasion were determined by performing the transwell assay. Protein expression levels of the proteins hexokinase 2 (HK2), matrix metalloproteinase-2 (MMP2), matrix metalloproteinase-9 (MMP9) and TAGLN2 were analyzed using western blots. The interaction between miR-625-5p and circ_0034642 or TAGLN2 was proved using a dual-luciferase reporter system. Animal models were established by subcutaneously injecting glioma cells stably transfected with sh-NC or sh-circ_0034642. Circ_0034642 and TAGLN2 were overexpressed whereas miR-625-5p was expressed at low levels in glioma tumors and cells. Moreover, circ_0034642 and TAGLN2 were upregulated while miR-625-5p was downregulated under hypoxic conditions in a time-dependent manner. Next, elimination of circ_0034642 was shown to inhibit cell glycolysis, proliferation, migration and invasion under hypoxic conditions in gliomas. Then, we found that circ_0034642 acted as a “sponge” of miR-625-5p while TAGLN2 acted as a target of miR-625-5p. In addition, recovery of circ_0034642 attenuated the repression mediated by miR-625-5p on glioma cell glycolysis and progression under hypoxic conditions. Meanwhile, an inhibitor of miR-625-5p alleviated TAGLN2 deficiency-induced inhibition of glioma cell development under hypoxic conditions. We also discovered that circ_0034642 could interact with miR-625-5p and further alter the expression of TAGLN2. Lastly, a circ_0034642 knockdown hindered tumor growth in vivo by regulating the miR-625-5p/TAGLN2 axis. Enhanced expression of circ_0034642 was found to promote cell glycolysis, proliferation, migration and invasion under hypoxic conditions in gliomas by sponging miR-625-5p to improve TAGLN2 expression, providing prospective biomarkers for the diagnosis of glioma.

The B′-site alkali metal ion (B′ = Li, Na, K, and Rb) in a series of hexacyanocobaltate-based organic–inorganic hybrid compounds (HIm)2[B′Co(CN)6] (HIm = imidazolium cation) plays a key role in the change of the framework structures and the dynamic behaviours of the guest. As a result, the associated bulk dielectric properties are also changed.

The Fenton reaction is regarded as an advanced oxidation process that can efficiently remediate environmental pollutants. However, the one-time irreversible consumption of its catalysts raises the cost in practical application. Herein, we report the generation of active Fe2+ sites via photo-reduction by photogenerated electrons on a TiO2 nanotube-based catalyst (TNT(Pd)/Fe2O3) with Fe2O3 decorated on the outside wall, while the inside cavity entrapped Pd nanoparticles. Fenton catalytic investigations under visible light show that TNT(Pd)/Fe2O3 displays superior methyl orange degradation activity with 90% removal in 10 minutes. The kinetic constant is 4.3 times as the sum of the pure photocatalysis and Fenton catalytic kinetic constants. The synergistic effect between the Fenton and photocatalytic reactions is further evidenced by the photocurrent and photodegradation tests. The TNT(Pd)/Fe2O3 catalyst showed no decay in the Fenton-photocatalytic performance over three successive cycles. XPS measurements after long-term stability tests revealed no loss, but a slight increase in the number of Fe2+ species. All of these results suggest that the most active Fe2+ species in the Fenton reaction can be regenerated via the reduction by photogenerated electrons. This work addressed the challenge in catalyst regeneration in the traditional Fenton reaction via photoreduction by rational combination with a photocatalyst and the realized synergistic effect between photocatalysis and the Fenton reaction.

Two-dimensional (2D) structured black arsenic phosphorus (B-AsP) compound materials play a pivotal role in a wide range of applications due to their exotic physical properties and flexible architectures. Here, 2D B-AsP compound materials were synthesized via mineralization-assisted gas phase transport. High-resolution X-ray diffraction (HRXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the composition and crystal structures of the B-AsP flakes. The results show that the synthesized B-AsP has good crystallinity and composition close to the designed value. B-AsP compound materials are new materials with a high theoretical specific capacity and can be used as negative electrodes in lithium ion batteries (LIBs). These materials show a higher specific capacity in their first charge/discharge cycle than graphite. These data provide basic support for research on the energy storage capacity of B-AsP compound materials. The results have great potential for improving the performance of lithium ion batteries.

Marine oil spills often cause long-term harm to the polluted environment. The absence of many important components makes it more difficult to identify the source of an oil spill. Traceability identification of seriously weathered oil spill has always been a difficult task due to the influence of the complicated weathering process. Therefore, it is particularly important to screen and verify the new indexes to solve the problem of identification of severe weathering oil spill. As a kind of common biomarker, the bicyclic sesquiterpanes represent a research hotspot in the field of identification of oil spills. The stability and applicability of bicyclic sesquiterpanes in oil spills in different time points have been assessed by comparing laboratory simulation weathering experiment and beach weathering experiment samples. By using the commonly used oil spill identification method including the t-test, similarity method and repeatability limit method, 12 new diagnostic ratios (DRs) of bicyclic sesquiterpanes were screened and appraised. These diagnostic ratios are applicable to the identification of unweathered crude oil samples obtained from different regions. In both severe weathering processes, only the ratio of total pentamethyldecahydronaphthalene to total pentamethyldecahydronaphthalene and hexamethyldecahydronaphthalene remained relatively stable. This has a good potential for the identification of the source of severe weathering oil spills. If it has been verified by a variety of oil products, it can be recommended as the identification index of severe weathering oil spills.

Considering p-arsanilic acid (p-ASA) as an organoarsenic pollutant, monitoring concentration of p-ASA is significant to maintain environmental security. Photoelectrochemical (PEC) detection is promisingly applied in environmental monitoring for its lower cost and simpler operation, compared to traditional techniques. However, general electrode materials of PEC sensors need to be modified with biological probes due to lack of specific binding sites to analytes, which may lead to complicated sensor fabrication and bio-recognizers inactivation during storage. Herein, a porphyrinic metal–organic framework/reduced graphene oxide (PCN-224/rGO) nanocomposite with simultaneously excellent photoelectric activity and strong binding characteristics was prepared and used to fabricate a PEC sensor for p-ASA detection avoiding the modification of bio-recognizers. Benefiting from the high conductivity of rGO, the separation efficiency of charge carriers was improved in PCN-224/rGO and thereby photocurrent gained an amplification of about 12 times. The PCN-224/rGO nanocomposite had strong affinity to p-ASA via Zr–O–As coordination and π–π stacking. Significantly, the binding of p-ASA could adjust the band position of PCN-224/rGO and facilitate oxygen reduction by releasing more photogenerated electrons, achieving photocurrent enhancement. The developed PEC sensor had a wide detection range, from 10 ng L−1 to 10 mg L−1, with a detection limit of 5.47 ng L−1. Furthermore, the sensor was successfully applied to monitor p-ASA in simulated natural water and swine manure lixivium. This study paved the way for the design of more efficient PEC sensors for environmental monitoring.

From the view of nanostructures, hierarchical lamellar heterostructures are one of the ideal candidates for high-performance electrode materials. Herein, hierarchical lamellar Co3O4–CoMoO4 heterostructures (Co3O4–CoMoO4 HLHs) are synthesized via a facile solvothermal approach with subsequent annealing treatment. The obtained HLHs consist of lamellar parallel stacked CoMoO4 nanosheets, where Co3O4 nanoflakes uniformly grow into an array on the surface of CoMoO4 nanosheets. The formation mechanism of Co3O4–CoMoO4 HLHs can be attributed to the sequential precipitation of CoMoO4 and Co3O4 precursors during the solvothermal process. The early nucleated parallel stacked 2D nanosheets serve as templates for the growth of Co hydroxide nanoflake arrays. Owing to the structural advantage, the as-obtained Co3O4–CoMoO4 HLHs endow the constructed electrode with enhanced electrochemical activity, high specific capacity and long-term cycling stability.

Malignant melanoma is a highly lethal disease, and advanced stages of melanoma have proven to be resistant to many chemotherapeutic drugs. Cancer stem cells (CSCs) and high levels of intracellular glutathione (GSH) have been proven to play important roles in drug resistance. Retinoic acid (RA) is a promising anticancer agent, which can inhibit proliferation and induce differentiation of CSCs, but its clinical use has been limited by its water insolubility and weak cancer cell killing effect when used alone. Herein, by combining RA and ferrocene, a new type of derivative of retinoic acid (FCRA) was synthesized and then oxidized by FeCl3. The oxidized FCRA (FCRA+) was exploited as a novel anticancer agent. Compared with RA, FCRA+ not only has improved water solubility and stronger anti-cancer effect to melanoma cells through depleting intracellular GSH of the cancer cells, but also can inhibit proliferation and induce differentiation of melanoma CSCs, such as free RA. Therefore, FCRA+ has better application prospects than RA and may replace RA for clinical applications.

An unprecedented meso-decorated pillar[5]arene derivative, EtP5A-DPE, embedded with a TPE unit was prepared and structurally characterized. In the crystal, the incubation of the guest 1,4-dicyanobutane molecule inside the tetraphenylethene-embedded pillar scaffold induces a significant change in the molecular conformation, shutting down the AIE emission of this compound.

Modifying the interfacial conditions of magnetic layers by capping with overlayers can efficiently enhance the magnetic functionality of a material. However, the mechanisms responsible for this are closely related to the crystalline structure, compositional combinations, and interfacial quality, and are generally complex. In this contribution, we explored the use of Ag ultrathin overlayers on annealed . A method for preparing magnetic layers with different levels of enhanced magnetic anisotropy energy was developed. The method essentially involves simply modifying the contact area of the metallic/magnetic interface. A rougher interface results in a larger contact area between the Ag and Ni layers, resulting in an increase in magnetic anisotropy energy. Moreover, post-annealing treatments led to the segregation of Ni atoms, thus making the enhancement in the coercive force even more efficient. A model permits an understanding of the contact area and a strategy for enhancing the magnetic anisotropy energy and the coercive force was developed. Our approaches and the developed model promise to be helpful in terms of developing potential applications of ultrathin magnetic layers in the area of spintronics.

Co–Al layered-double-oxides (LDOs) derived from inorganic anion (nitrate, carbonate, sulfate and phosphate) pillared Co–Al layered-double-hydroxides (LDHs) were synthesized. These LDO samples exhibited impressive catalytic performances in oxidative dehydrogenation of propane (ODHP) at low temperatures. Characterization techniques such as XRD, TEM, H2-TPR and O2-TPD were used to measure the physicochemical properties of the samples. The results showed that the LDO samples consisted of homogeneously mixed cobalt spinel oxides (Co2AlOx) containing both Co(III) and Co(II). Co(III) instead of Co(II) was linked with the active sites for ODHP at low temperatures. The sulfate and phosphate anions were preserved in the corresponding LDO samples, unlike the nitrate and carbonate pillars. Sulfate (phosphate) around the cobalt decreased the size of the spinel oxide particles more relative to nitrate and carbonate, and so the dispersion of CoOx in the LDO and the selectivity to propylene in ODHP over these catalysts were improved. Both surface adsorbed oxygen species and surface lattice oxygen species were significantly found over the phosphate-pillared LDO, but only lattice oxygen species were available over the sulfate-pillared LDO. Different mechanisms of propane activation were exhibited over these LDO samples for ODHP.

Semiconductor-based heterogeneous photocatalysis has received considerable attention as an alternative promising approach to alleviate the globally increasing energy demand and environmental concerns. As promising candidates, one dimensional (1D) CdS nanostructures have gained growing interest due to their unique advantages, including a narrow band gap, suitable band edge positions, high aspect ratio structure with low reflectance, and excellent electronic charge transfer. This review summarizes a panorama of the latest progress related to the design and construction of 1D CdS based photocatalysts with boosted performance, involving constructing 1D solid solution, loading cocatalysts, coupling with semiconductors, hybridizing with carbon-based materials and functionalization with biocatalysts. Finally, some challenges and opportunities for future exploration of 1D CdS based photocatalysts are critically discussed. It is anticipated that this review will afford enriched information on the rational utilization of 1D CdS materials with ameliorated performances by harnessing their inherent merits, and particularly stimulate further developments of low dimensional heterostructures towards various artificial photoredox reactions.

Two non-centrosymmetric crystals, [(H2dabco)(H2O)](ClO4)2 (1; dabco = 1,4-diazabicyclo[2.2.2]octane) and [(H2dabco)(H2O)](BF4)2 (2), were synthesized and characterized, along with their deuterated species [(D2dabco)(D2O)](ClO4)2 (3) and [(D2dabco)(D2O)](BF4)2 (4). The polar structures are formed by the directional packing of the asymmetric hydrogen-bonded supramolecular unit [(H2dabco)(H2O)] and stabilized by hydrogen bonds among the cations and the anions. Meanwhile, these compounds undergo phase transitions in the temperature range of 230–250 K, revealed by differential scanning calorimetry and dielectric constant measurements. Crystal structure analysis and deuteration study indicate that the order–disorder transition of the anions is the main driving force for the phase transitions in 1 and 2.

Silver-mediated direct trifluoromethoxylation of α-diazo esters and ketosteroid was disclosed. The reactions of alkyl α-diazo arylacetates with AgOCF3 or CF3SO2OCF3/AgF at -30 to 10 °C under a N2 atmosphere provided α-trifluoromethoxyl arylacetates in up to 90% yield, while alkyl α-diazo vinylacetates reacting with CF3SO2OCF3/AgF or AgOCF3 afforded γ-trifluoromethoxyl α,β-unsaturated esters in up to 94% yield. The α-diazo ketosteroid was also trifluoromethoxylated under the standard reaction conditions. This protocol allows for an effective and convenient access to a large number of synthetic building blocks, which are promising in the development of new functional OCF3-molecules.

A novel synthesized 4-carboxylphenoxy-decorated tetraphenylethene and α-cyclodextrin could form a host–guest inclusion complex with molecular RIM-induced Emission. On the basis of this, the TPE-COOH⊂α-CD inclusion complex exhibits a reversible fluorescence intensity change response to the photo-isomerization of 4-(phenylazo)benzoic acid (PBA) under alternate UV- and visible-light irradiation.

Mixing of the B′-site alkali metals in the hybrid double perovskite crystals (CH3NH3)2[K1−xRbxCo(CN)6] (x = 0.23–0.62) results in a fine tuning of the phase transition temperatures and therefore the switchable dielectric constant properties. The correlations among the phase transition temperature Tc, radius of the B′-site metal ion rB′, molar ratio x and extended tolerance factor t are established as rB′ = (1 − x)rK + xrRb, x = −13.2 + 0.645Tc1/2, rB′ = −32.4 + 9.02Tc1/2 and t = 513/(14x + 616). These findings indicate the efficiency and practicability of the B′-site mixing method for tuning the phase transition-related properties of the hybrid perovskites.

Great interest in heterogeneous asymmetric catalysis has focused on obtaining an enantioselective cascade reaction through a controllable active site-isolated heterogeneous catalyst. Herein, we utilize a yolk–shell-structured mesoporous silica and assemble an active site-isolated bifunctional heterogeneous catalyst, where chiral cinchonine-based squaramide molecules are anchored within a silicate channel as an outer shell while amine-functionalities are entrapped onto a silicate yolk as an inner core. Structural analyses and characterizations of the heterogeneous catalyst reveal its well-defined single-site chiral active species within its silicate network. Electron microscopy confirms the yolk–shell-structured mesoporous material. As presented in this study, as a bifunctional heterogeneous catalyst, it enables an efficiently nitroaldol–Michael cascade reaction to conduct the three-component coupling of nitromethane, aldehyde and acetylacetone into various chiral diones with high yields and up to 99% enantioselectivities in a one-pot process. As expected, this active site-isolated catalyst not only enhances the catalytic selectivity of the first-step nitroaldol condensation, but also keeps the enantioselectivity of the second-step Michael addition. Moreover, the heterogeneous catalyst can be also recovered easily and recycled repeatedly, making it an interesting feature in a three-component organic transformation.

Ge/Si and Si/Ge core-shell nanowires (NWs) have substantial potential for application in many kinds of devices. Because impurity distributions in Ge/Si and Si/Ge core-shell NWs strongly affect their electrical properties, which in turn affect device performance, this issue needs urgent attention. Here we report an atom probe tomographic study of the distribution of boron (B), one of the most important impurities, in two kinds of NWs. B atoms were doped into the Si regions of Ge/Si and Si/Ge core-shell NWs. It was found that the B atoms were randomly distributed in the Si shell of the Ge/Si core-shell NWs. In the Si/Ge core-shell NWs, on the other hand, the B distributions depended on the growth temperature and the B2H6 flux. With a higher growth temperature and an increased B2H6 flux, the B atoms piled up in the outer region of the Si core. However, the B atoms were observed to be randomly distributed in the Si core after decreasing both the growth temperature and the B2H6 flux.

Trifluoromethylthiolation and trifluoromethylselenolation of alkynyl(phenyl)iodonium tosylates by [XCF3]− (X = S, Se) ions was accomplished in 5–10 minutes at room temperature under a N2 atmosphere and provided a variety of alkynyl trifluoromethyl sulfides and selenides in good yields. Compared to the known methods, this approach has several advantages such as short reaction times and metal- and additive-free conditions without needing excess [Me4N][XCF3] reagents. Moreover, the less efficient reactions of (phenylethynyl)benziodoxol(on)e with [Me4N][XCF3] under the standard conditions demonstrate that acyclic alkynyl(phenyl)iodoniums are more powerful alkynyl sources in the conversion. This protocol allows for a fast and convenient access to numerous alkynyl trifluoromethyl sulfides and selenides.

A new thiourea-based supramolecular compound (TA)[(TU)2Cl] (1, TA = thiazolium, TU = thiourea) has been successfully synthesized and systematically characterized, including differential scanning calorimetry (DSC), variable-temperature structural analysis and dielectric measurements. 1 undergoes a structural phase transition at 213.7 K (Tc), accompanied by distinct switchable dielectric anomalies. The TA cation is disordered over four equivalent positions above the Tc and becomes less-disordered over the two equivalent positions below the Tc. The structural relative disorder-order transition of the TA cation contributes to the switching of the dielectric constant between high- and low-dielectric states. Supramolecular inclusion compounds designed with dynamic components have been proved to be a good strategy for searching for new phase transition and switchable dielectric materials.

A reversible phase transition and phase transformation double-adjustable compound (BEDABCO)ClO4·H2O (1) and its analogs (BEDABCO)ClO4·D2O (2), (CEDABCO)ClO4·H2O (3) and (BEDABCO)BF4·H2O (4) were synthesised and studied (BEDABCO = 1-(2-bromoethyl)-1,4-diazabicyclo[2.2.2]octane, CE = chloroethyl group). It was found that all the compounds exhibit reversible phase transitions owing to the swing-like movement of the water molecules. Strength change of the anion-based hydrogen bonds controls the phase transition temperature point, e.g. the temperature point of 4 shows a decrease of about 30 K compared to 1. Upon heating–cooling cycles, the water molecules partially escape from the crystals, which can transform into dehydrated unsteady states and recover the rehydrated states at room humidity (30–40% RH) by reversible de/absorption of the water molecules. The phase transition and transformation properties based on the water quantity in the crystal lattices can be used to develop time switches and water catchers or new water sensor devices.

One-dimensional (1D) nanostructures aligned on a conductive substrate are advantageous for various energy applications. In this work, we report the synthesis of hierarchically nanostructured NiO nanotube arrays supported on carbon fiber paper (CFP) via a simple ZnO-template method and evaluated the arrays as supercapacitor electrodes. We demonstrate that subtle changes in the annealing temperature during the preparation of NiO affect the porous structures of both NiO and CFP, which synergically enhance the pseudocapacitive performance of NiO according to in-depth electrochemical analyses.

Three-dimensionally ordered mesoporous carbons (3DOmCs) with pore sizes in the range of 10–40 nm are prepared and utilized as anode electrode materials for lithium-ion batteries (LIBs). Regardless of pore size, the capacity of the 3DOmCs is substantially dictated by their surface area because Li+ adsorption on the surface becomes an important mechanism of Li+ storage along with lithium intercalation into graphene layers. Interestingly, we determine that simple NH3 heat-treatment is a facile and effective way to simultaneously increase the surface area and improve the electrical conductivity of the 3DOmCs, which results in increased capacity of the resulting N-doped 3DOmCs compared to their parent counterparts.

One-dimensional (1D) CdS nanowire (NW)–two-dimensional (2D) BiVO4 nanosheet (NS) heterostructures (CdS–BiVO4 1D/2D HSs) have been fabricated toward visible-light driven selective fine-chemical synthesis in water under controlled reaction conditions. Good interfacial contact in the heterostructures is achieved through a simple and efficient electrostatic self-assembly synthetic methodology, which is afforded by the substantial attraction between two materials with opposite surface charge. These 1D/2D interfacial heterostructures are able to facilitate charge separation and transport between 1D CdS NWs and 2D BiVO4 NSs. Characterization results indicate that the markedly enhanced photocatalytic activity of CdS–BiVO4 1D/2D HSs is attributed to the introduction of 2D BiVO4 NSs, which serve as favourable receptors for efficient separation of photo-generated charge carriers excited from 1D CdS NWs. This work is expected to stimulate an increasing interest in coupling semiconductor photocatalysts with dissimilar dimensionalities for various applications in solar energy conversion.

This Letter is a reply to the preceding comment by Szafranski. We suggest that other probabilities could exist besides Szafranski's assertion on the phase transitions of the crystals and point out how the present experiments and conclusions can be solidified by additional investigations.

The key C–C bond forming step of the Rh-catalysed carboxylation of organoboron compounds with CO2 was investigated by density functional theory (DFT) at the IEFPCM/PBE0/DGDZVP level of theory. With a bidentate phosphane (dppp) ligand, the reaction begins with a transformation from square-planar O-(η1)-bonded to distorted-tetrahedral, η2-bonded CO2 followed by migratory insertion (barrier 12.7 kcal mol−1). The calculations showed that incorporation of electron-donating substituents within either the aryl substrate or the phosphane leads to a slight decrease of the reaction barrier, in excellent agreement with the experimental trends. With a diene ligand (cod), the migratory insertion proceeds directly from the O-(η1)-bonded CO2 (barrier 17.1 kcal mol−1) as a consequence of the diminished σ-donor ability of the diene ligand. Therefore, the diene ligand is predicted to be an inferior choice compared to the diphosphane. Testing of [(cod)Rh(OH)]2 upon completion of the computations showed no conversion.

Inhalatory and dermal exposures of on-duty vehicle inspection workers to polycyclic aromatic hydrocarbons (PAHs) in Beijing were investigated from April 18 to May 17, 2011. Exposure levels to particulate PAHs for the vehicle inspection workers at gasoline, bus and diesel lines were found to be 56.07 ng m(-3), 111.72 ng m(-3) and 199.80 ng m(-3), respectively. A probabilistic risk assessment framework was integrated with the toxic equivalence factors (TEFs) and the incremental lifetime cancer risk (ILCR) approaches to quantitatively estimate the exposure risk for vehicle inspection workers of the three work lines. The median values of inhalation risk were estimated to be 3.7 × 10(-7), 5.0 × 10(-7) and 1.37 × 10(-6), respectively, while the median dermal ILCR values were 7.05 × 10(-6), 6.98 × 10(-6) and 1.28 × 10(-5), respectively for gasoline, bus, and diesel inspection workers. Total ILCR was higher than the acceptable risk level of 10(-6), indicating unacceptable potential cancer risk.

While the number of man-made nano superstructures realized by self-assembly is growing in recent years, assemblies of conductive polymer nanocrystals, especially for superlattices, are still a significant challenge, not only because of the simplicity of the shape of the nanocrystal building blocks and their interactions, but also because of the poor control over these parameters in the fabrication of more elaborate nanocrystals. Here, we firstly report a facile and general route to a new generation of 3D layered superlattices of polyaniline doped with CSA (PANI-CSA) and show how PANI crystallize and self-assemble, in a suitable single solution environment. In cyclohexane, 1D amorphous nanofibers transformed to 1D nanorods as building blocks, and then to 2D single-crystal nanosheets with a hexagonal phase, and lastly to 3D ordered layered superlattices with the narrowest polydispersity value (M(w)/M(n) = 1.47). Remarkably, all the instructions for the hierarchical self-assembly are encoded in the layered shape in other non-polar solvents (hexane, octane) and their conductivity in the π-π stacking direction is improved to about 50 S cm(-1), which is even higher than that of the highest previously reported value (16 S cm(-1)). The method used in this study is greatly expected to be readily scalable to produce superlattices of conductive polymers with high quality and low cost.

Particle-associated polycyclic aromatic hydrocarbon (PAH) concentrations were investigated at eight sampling sites during cold periods where heating is used (heating period) (February to March, 2005) and warm periods where heating is not required (non-heating periods) (August to September 2006) in the urban area of Anshan, an iron and steel city in northeastern China. Eleven PAH species were measured using GC-MS. The total average concentrations of PAHs ranged from 46.14 to 385.60 ng m(-3) in the heating period and from 5.28 to 146.40 ng m(-3) in the non-heating period. The lowest concentration of ∑PAHs was observed at Qianshan, a monitoring site far from the city and industrial area, and the highest concentration occurred in the site located at the factory area of Anshan Iron and Steel Incorporation. Moreover, ambient PAH profiles were studied and high molecular weight PAH (including 4-6 rings) species occurred in the high fractions. Toxic equivalent factors analysis gave the potential carcinogenic risks in Anshan. For the heating sampling period, BaP equivalent concentration is in the range of 41.98 to 220.83 ng m(-3), and 9.23 to 126.00 ng m(-3) for the non-heating sampling period. By diagnostic ratio analysis, traffic emission and combustion (coal or biomass) were potential sources for PAHs in Anshan. Finally, PCA results indicated the major sources were vehicle emission, steel industry emission, and coal combustion for both heating and non-heating seasons, which agreed with the results from the diagnostic ratio analysis.

We report self-assembly of charge-stabilized gold and silver nanoparticles at water-air and water-oil interfaces, via manipulation of the interactions between the interfaces and the adsorbing nanoparticles. Nanoparticle adsorption from bulk colloids to an interface is an energy-favored, but finite sorption barrier-restrained (kinetics-controlled) process. Consequently, to successfully mediate self-assembly of nanoparticles, the finite sorption barrier should be decreased. That can be accomplished by manipulating its three controlling forces: the repulsive electrostatic force, the repulsive van der Waals force, and the attractive hydrophobic force between the interface and the adsorbing nanoparticles. It was found that hydrophobic coatings change nanoparticle hydrophobicity and greatly increase the attractive hydrophobic force. Surface active organic solvents (methanol, ethanol, isopropanol, and acetone) decrease the attractive hydrophobic force to some extent. However, they decrease the repulsive electrostatic force to a larger extent, via a "charge dilution" mechanism, due to their positive adsorption at the charged water-air and water-oil interfaces. Hydrophobic coatings and organic solvents consequently decrease the sorption barrier, facilitate nanoparticles overcoming the sorption barrier, and mediate the self-assembly of nanoparticles.

Transparent heterogeneous ultrathin films of exfoliated layered double hydroxide (LDHs) nanosheets, fabricated alternately with polyanion, have been obtained via a layer-by-layer electrostatic self-assembly which yields a series of novel LDH films with potential multifunctionality.

Two new highly oxygenated nortriterpenoids with a unique norcycloartane skeleton, micrandilactones B and C, were isolated from Schisandra micrantha; micrandilactone C exhibited an EC50 value of 7.71 microg/mL (SI > 25.94) against HIV-1 replication with minimal cytotoxicity, and the potent anti-HIV-1 activity and unique structural features of make it a promising lead for therapeutic development of a new generation of anti-HIV drug.