A facile solution-chemistry method for Cu(OH)2 nanoribbon arrays with noticeable electrochemical hydrogen storage ability at room temperature

Cu(OH)(2) nanoribbon arrays were synthesized by a simple room-temperature solution reaction for the first time, which exhibited noticeable hydrogen storage capacity and large BET surface area.     

One-pot, large-scale synthesis of SnO2 nanotubes at room temperature

SnO(2) nanotubes were synthesized via a one-pot redox route at room temperature, in which the Kirkendall effect is definitely responsible for the formation of hollow structures.     

Preparation of two-dimensional molybdenum disulfide for NO2 detection at room temperature

In this work, the two-dimensional MoS₂ film was prepared by sulfuring the molybdenum atomic layer on SiO₂/Si substrate. The reaction temperature, heating rate, holding time and carrier gas flow rate were investigated comprehensively. The quality of MoS₂ film was characterized by optical microscopy, atomic force microscopy, Raman and photoluminescence spectroscopy. The characterization results showed that the optimum synthesis parameters were heating rate of 25 °C/min, reaction temperature of 750 °C, holding time of 30 min and carrier gas velocity of 100 sccm. The MoS₂ gas sensor was fabricated and its gas sensing performance was tested. The test results indicated that the sensor had a good response to both reducing gas (NH₃) and oxidizing gas (NO₂) at room temperature. The sensitivity to 100 ppm of NO₂ was 31.3%, and the response/recovery times were 4 s and 5 s, respectively. In addition, the limit of detection could be as low as 1 ppm. This work helps us to develop low power and integrable room temperature NO₂ sensors.     

Bis(ammonium) fluorophosphate at room temperature

The title room‐temperature phase of (NH₄)₂(PO₃F) is orthorhombic (Pna2₁) and is related to the β‐K₂SO₄ structure family. The title structure consists of ammonium cations, NH₄⁺, and fluoro­phosphate anions, (PO₃F)^2?. These ions are connected by N—H?O hydrogen bonds. Two‐centre N—­H?F hydrogen bonds are not present in the structure. Phase transitions were detected at 251±2 and 274±2 K during cooling and heating, respectively.     

Rotational energy transfer in NO (A 2Sigma+,v'=0) by N2 and O2 at room temperature

State-to-state rotational energy transfer (RET) rate coefficients for NO (A 2Sigma+, v'=0, J=5.5, 11.5, 17.5) were measured for N2 and O2 at room temperature using a pump-probe method. The NO A 2Sigma+ state is prepared by 226 nm light and the RET is monitored by fluorescence from the D 2Sigma+ v'=0 state, following excitation by a time-delayed laser at approximately 1.1 microm. Additionally, total collisional removal and final state distributions were measured exciting in the Q1+P21 band head, to simulate an NO laser-induced fluorescence atmospheric monitoring scheme. Time-resolved modeling is used to understand relaxation mechanisms and predict relaxation times in ambient air. H2O at atmospherically relevant concentrations does not affect the degree of RET in ambient air.     

Effect of reduction treatment on copper modified activated carbons on NO(x) adsorption at room temperature

Activated carbon was impregnated with copper salt and then exposed to reductive environment using hydrazine hydrate or heat treatment under nitrogen at 925 °C. On the obtained samples, adsorption of NO(2) was carried out at dynamic conditions at ambient temperature. The adsorbents before and after exposure to nitrogen dioxide were characterized by X-ray diffraction (XRD), thermal analysis, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS), N(2)-sorption at -196 °C, and potentiometric titration. Copper loading improved the adsorption capacity of NO(2) as well as the retention of NO formed in the process of NO(2) reduction on the carbon surface. That improvement is linked to the presence of copper metal and its high dispersion on the surface. Even though both reduction methods lead to the reduction of copper, different reactions with the carbon surface take place. Heat treatment results in a significant percentage of metallic copper and a reduction of oxygen functional groups of the carbon matrix, whereas hydrazine, besides reduction of copper, leads to an incorporation of nitrogen. The results suggest that NO(2) mainly is converted to copper nitrates although the possibility to its reduction to N(2) is not ruled out. A high capacity on hydrazine treated samples is linked to the high dispersion of metallic copper on the surface of this carbon.     

Stable bis(2-chloro-2,2-difluoroethoxy)-fluoromethyl cation at room temperature

A stable carbocation was prepared by reacting bis(2-chloro-2,2-difluoroethyl) difluoroformal with SbF₅. The carbocation's structure was confirmed by ¹⁹F, ¹H and ¹³C NMR measurements. The carbocation is stable at room temperature for more than 2 weeks and was converted into the corresponding carbonate when reacted with water.     

Negatively charged pi-(C60-)2 dimer with biradical state at room temperature

A negatively charged pi-(C60-)2 dimer bonded by two single bonds was found in the ionic multicomponent complex {(MDABCO+).CoIITMPP}2.(C60-)2.(C6H4Cl2)2.5.(C6H5CN)1.5 (1). In contrast to the previously described diamagnetic sigma-(C60-)2 dimer, the negatively charged pi-dimer has a biradical state at room temperature: (C60*-)2 (S = 1). The behavior of spins in this dimer can be described by a model with a singlet ground state (S = 0) and a close lying excited triplet (S = 1) state with the energy gap of 2|JAF| = 70 +/- 2 cm-1. On the whole, complex 1 shows a strong antiferromagnetic interaction of spins with a Weiss constant of -34 K.     

Optimization of strontium- doping concentration in BaTiO3 nanostructures for room temperature NH3 and NO2 gas sensing

In this study, we comprehensively present the gas sensing performance of strontium (Sr)-doped barium titanate (BaTiO₃) nanostructures which are synthesized by a low-temperature hydrothermal route. The in-situ doping of strontium in BaTiO₃ nanostructures is achieved with different molar concentrations of Sr, and the sensing performance was evaluated by screen printing process of products to form their thick films. The thick films of as-prepared Sr-doped BaTiO₃ (BaSrTiO₃) were investigated for gas sensing performance for various gases at different operating temperatures where strong response was observed for both nitrogen dioxide (NO₂) and ammonia (NH₃) gases at room temperature. Furthermore, the sensing response at room temperature for NH₃ and NO₂ gases was also studied with respect to Sr doping concentrations in BaTiO₃ nanostructures.     

Copper(II)-mediated o-arylation of 3-hydroxy-2-oxindoles with boronic acids at room temperature

Synthesis of 3-aryloxy-2-oxindole derivatives from 3-hydroxy-2-oxindoles and aryl boronic acids through copper(II)-promoted reaction is achieved. This reaction provides an efficient protocol for the coupling between aryl boronic acid and tertiary aliphatic alcohol, opening a new avenue to format corresponding 3-phenyl-3-aryloxy-2-oxindole core, which has potentially value in the field of life-science.     

Photochemical investigation of Roussin's red salt esters: Fe2(mu-SR)2(NO)4

The photochemistry of various Roussin's red ester compounds of the general formula Fe(2)(SR)(2)(NO)(4), where R = CH(3), CH(2)CH(3), CH(2)C(6)H(5), CH(2)CH(2)OH, and CH(2)CH(2)SO(3)(-), were investigated. Continuous photolyses of these ester compounds in aerated solutions led to the release of NO with moderate quantum yields for the photodecomposition of the ester (Phi(RSE) = 0.02-0.13). Electrochemical studies using an NO electrode demonstrated that 4 mol of NO are generated for each mole of ester undergoing photodecomposition. Nanosecond flash photolysis studies of Fe(2)(SR)(2)(NO)(4) (where R = CH(2)CH(2)OH and CH(2)CH(2)SO(3)(-)) indicate that the initial photoreaction is the reversible dissociation of NO. In the absence of oxygen, the presumed intermediate, Fe(2)(SR)(2)(NO)(3), undergoes second-order reaction with NO to regenerate the parent cluster with a rate constant of k(NO) = 1.1 x 10(9) M(-1) s(-1) for R = CH(2)CH(2)OH. Under aerated conditions the intermediate reacts with oxygen to give permanent photochemistry.     

NO adsorption on the stoichiometric and reduced SnO2(110) surface

The adsorption of NO molecules on the perfect and defective (110) surfaces of SnO₂ was studied with first-principles methods at the density-functional theory level. It was found that NO mainly interacts via the nitrogen atom with the bridging oxygens of the stoichiometric surface while the coordinatively unsaturated surface Sn atoms are less reactive. On the oxygen-deficient surface, NO is preferentially adsorbed at the vacancy positions, with the nitrogen atom close to the former surface oxygen site. Regardless of the adsorption site, the unpaired electron is located mainly on the NO molecule and only partly on surface Sn atoms. The results for the SnO₂ surface are compared to literature results on the isostructural TiO₂ rutile (110) surface. Dedicated to Professor Karl Jug on the occasion of his 65th birthday     

在钾 / 乙二胺中的室温光诱导S~R~N1反应

在室温下 K / (NH~2CH~2)~2中, 氯萘和4-溴二苯与碳负离子发生Photo-S~R~N1反应, 阴碳离子来自乙酸叔丁酯,吗啡丙酯, 乙腈或丙腈. 与K / NH~3体系中的Photo-S~R~N1反应相比, ArNu的产率减少到50％左右, 而ArH的产率增加.     

Photochemical preparation of CdS hollow microspheres at room temperature and their use in visible-light photocatalysis

CdS hollow microspheres have been successfully prepared by a photochemical preparation technology at room temperature, using polystyrene latex particles as templates, CdSO₄ as cadmium source and Na₂S₂O₃ as both sulphur source and photo-initiator. The process involved the deposition of CdS nanoparticles on the surface of polystyrene latex particles under the irradiation of an 8 W UV lamp and the subsequent removal of the latex particles by dispersing in dichloromethane. Photochemical reactions at the sphere/solution interface should be responsible for the formation of hollow spheres. The as-prepared products were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Such hollow spheres could be used in photocatalysis and showed high photocatalytic activities in photodegradation of methyl blue (MB) in the presence of H₂O₂. The method is green, simple, universal and can be extended to prepare other sulphide and oxide hollow spheres.     

N-heterocyclic carbene enabled rhodium-catalyzed ortho C(sp2)-H borylation at room temperature

We report a rhodium-catalyzed ortho C(sp²)-H borylation of 2-phenylpyridines using commercially available N-heterocyclic carbenes (NHCs) as ligand and pinacolatodiboron (B₂pin₂) as borylating reagent. The reaction could take place at room temperature, tolerating a wide range of functionalities and affording ortho borylated products in moderate to excellent yields. The current method is also applicable to gram-scale reaction with reduced catalyst loading.     

Towards ultrafine TiO2 nanocrystal at room temperature

Ultrafine titanium dioxide (TiO₂) nanocrystal has attracted enormous interest due to their unusual quantum and surface effects. Here, we propose a facile route to synthesize ultrafine anatase nanocrystal at room temperature via an aqueous sol–gel method using lactic acid (LA) and acetylacetone (Acac) as double chelators. Transmission electron microscopy (TEM) and size analyzer confirmed that TiO₂ nanocrystal in precursor possessed an average size of ~3 nm with a narrow size distribution. Crystal structure characterized by TEM and X-ray diffraction (XRD) indicated that TiO₂ nanocrystal to be anatase phase. The results of field emission scanning electron microscopy (FE-SEM) and BET surface area exhibited that TiO₂ xerogel powder had mono-dispersed particles size and large BET surface area up to 90 m²/g.     

Copper(0)-mediated radical polymerization of styrene at room temperature

The “living’/controlled radical polymerization (LRP) of styrene (St) at room temperature is rarely reported. In this work, copper(0) (Cu(0))-mediated radical polymerization of St at room temperature was investigated in detail. Dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF) as well as a binary solvent, tetrahydrofuran/1,1,1,3,3,3-hexafluoro-2-propanol were used as the solvents, respectively. Methyl-2-bromopropionate and ethyl 2-bromoisobutyrate were used as the initiators, respectively. The polymerization proceeded smoothly with moderate conversions at room temperature. It was found that DMF was a good solvent with the essential features of LRP, while DMSO was a poor solvent with uncontrollable molecular weights. Besides, the match among the initiator, solvent and molar ratios of reactants can modulate the livingness of the polymerization, and the proper selection of ligand was also crucial to a controlled process. This work provided a first example of Cu(0)-mediated radical polymerization of St at room temperature, which would enrich and strength the LRP technique.     

Copper(II) tetrafluoroborate catalyzed ring-opening reaction of epoxides with alcohols at room temperature

[reaction: see text] Efficient ring opening of different epoxides by reaction with representative alcohols is presented. These processes were carried out at room temperature and rely on the usefulness of commercial copper tetrafluoroborate as catalyst.