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Herein, we have investigated the host–guest inclusion complexes formed on interaction of the symmetric tetramethyl-substituted cucurbit[6]uril (TMeQ[6]) with glycine (Gly) under different conditions.

Single-crystal X-ray diffraction analysis, nuclear magnetic resonance (NMR), and other characterization methods are used to characterize the complexes formed by cyclopentano- cucurbit[6]uril (abbreviated as CyP6Q[6]) as a host interacting with p-aminobenzenesulfonamide (G1), 4,4'-diaminobiphenyl (G2), and (E)-4,4'-diamino-1,2-diphenylethene (G3) as guests, respectively. The experimental results show that these three aromatic amine molecules have the same interaction mode with CyP6Q[6], interacting with its negatively electric potential portals. The supramolecular interactions include non-covalent interactions of hydrogen bonding and ion-dipole between host and guest molecules. CdCl2 acts as a structureinducing agent to form self-assemblies of multi-dimensional and multi-level supramolecular frameworks that may have potential applications in various functional materials.

A symmetrical dicyclopentyl substituted cucurbit[6]uril (CyP2Q[6]) was synthesized, and crystallized under the conditions of 3 mol/L hydrochloric acid solution and the induction of ZnCl2. The crystal structure was characterized by X-ray single crystal diffractometer, 1H NMR and MS, and the results show that the crystal belongs to the monoclinic crystal system with P21/n space group, a = 13.095 (2), b = 33.002 (6), c = 15.770 (3), α = 90°, β = 102.828(5)°, γ = 90°, Z = 4, and a macroporous honeycomb structure appears in the crystal.

The host and guest supramolecular interactions between symmetric dicyclohexanocucurbit[6]uril (CyH2Q[6]) and 1H-benzotriazole (BTA) were investigated using nuclear magnetic resonance spectroscopy, isothermal titration calorimetry (ITC), MALDI-TOF mass spectrometry and single-crystal X-ray diffraction analysis. From the experimental results, it was concluded that there was a 1:1 mode of inclusion in BTA@CyH2Q[6]. In addition, the benzene ring of the BTA molecule entered the cavity of CyH2Q[6], while the triazole part was at the port of the CyH2Q[6], forming a supramolecular framework. According to ITC, the complexation process for BTA with CyH2Q[6] is exothermic and mainly driven by enthalpy.

The host-guest interactions between cyclopentanocucurbit-[6]uril(CyP6Q[6]) as host and six alkyl imidazolium hydrochloride as guests(g1, g2, g3, g4, g5, and g6) have been studied by various techniques, such as 1H NMR spectroscopy, isothermal titration calorimetry, mass spectrometry, and single-crystal X-ray diffraction analysis. The experimental results showed that CyP6Q[6] formed 1:1 inclusion complexes with each of guests g1–g6. The part of the guest entered the cavity of CyP6Q[6] changes as the alkyl chain increases in length. It can be seen that the length of the alkyl chain plays a key role in determining the mode of host-guest interactions.

Supramolecular interactions between symmetric dicyclohexanocucurbit[6]uril (CyH2Q[6]) and five benzene ring-containing guests have been studied by various techniques, such as X-ray crystallography,...

This paper reports on the supramolecular self-assembly of cyclopentano cucurbit[5]uril (CyP5Q[5]), L-phenylalanine (L-Phe), and cadmium ions. The crystal structure is characterized using X-ray diffraction. The results show that the complex belongs to a monoclinic system with P21 space group. Cd2+ and L-Phe are coordinated in two CyP5Q[5] portals via hydrogen bonds and ion-dipole interactions, respectively, so that the outer wall of the cucurbit[n]uril forms a porous channel. Each channel consists of six supramolecular chains, which may accommodate inorganic anions, such as CdCl $$_{4}^{{2 - }}$$ .

Binding behaviours between cyclopentanocucurbit[6]uril (CyP 6 Q[6]) and three amino acids have been investigated by means of X-ray crystallography, proton nuclear magnetic resonance spectroscopy and isothermal titration calorimetry. The results showed that CyP 6 Q[6] forms a 1 : 2 inclusion complex with glycine, but 1 : 1 complexes with both leucine and lysine. Whereas the carboxyl group of glycine can enter the interior of the cavity of CyP 6 Q[6], only the alkyl chains of leucine and lysine can enter this cavity. Interestingly, leucine can adopt two different self-assembly modes upon its interaction with cucurbituril, depending on the external conditions, whereas glycine and lysine do not exhibit such behaviour.

Since the first reportal on decamethylcucurbit[5]uril (Me10Q[5]) in 1992, substituted cucurbit[n]urils have attracted considerable research interest. In this study, the host–guest modes between the tetramethyl cucurbit[6]uril (TMeQ[6]) as a host and 4-chloroaniline and 4,4′-diaminostilbene (G1 and G2) as guests were investigated by single-crystal X-ray diffraction, NMR, ITC, UV-Vis spectrum, and MALDI-TOF mass spectrometry analyses. The experimental results showed that TMeQ[6] formed a 1 : 1 inclusion compound with G1, and the carbonyl portal of TMeQ[6] formed a 1 : 1 self-assembly with G2. Further, multi-dimensional supramolecular frameworks were formed driven by weak interaction forces in the system (hydrogen bonding, C–H⋯π interactions, ion–dipole interactions, and dipole–dipole interactions).

The host–guest binding characteristics of cyclopentanocucurbit[6]uril (CyP6Q[6]) and cyanine dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (t-DSMI) have been studied. The results show that CyP6Q[6] and t-DSMI form a 1:1 inclusion system, generating strong fluorescence. On this basis, the fluorescent probe t-DSMI@CyP6Q[6] has been constructed, and its anion recognition ability has been investigated. In a neutral environment, BF4−, H2PO4−, and I− elicit obvious specific responses from the probe, since they have stronger binding forces. This probe shows greater sensitivity than the previously reported probe t-DSMI@HMeQ[6]. Since the complex formed by CyP6Q[6] and t-DSMI can produce strong fluorescence at pH > 4.6, t-DSMI@CyP6Q[6] was constructed to recognize the anions at pH ≅ 5. The results show that in a near neutral environment, BF4−, H2PO4−, and I− elicit obvious specific responses from the probe.

In this paper, four supramolecular complexes were constructed by using cyclopentanocucurbit[5]uril (CyP5Q[5]) with CrCl3, CoCl2, HgCl2 and Pb(ClO4)2 respectively in 3 mol/L hydrochloric acid aqueous solution, and then Single-crystal X-ray diffraction was employed to characterize these supramolecular complexes: [C45H56Cl3CrN20O13(1), C45H60Cl8Co3N20O15(2), C45H64Cl6Hg2N22O13(3) and C90H112Cl8Pb4N40O55 (4)]. Interestingly, complex 4 is completely different from the other three complexes in that the Pb2+ is coordinated with all the five carbonyl groups of the CyP5Q[5] to form a one-dimensional supramolecular chain. It is worth noting that complex 3 is different from complex 1 and complex 2 in the way of coordination in which the central Hg2+ ion is not coordinated with water molecules but with two chloride ions, and with five portal carbonyl oxygen atoms of the CyP5Q[5], while the central Co2+ or Cr3+ is only partially coordinated with portal carbonyl oxygen atoms of the CyP5Q[5].

The reaction kinetics of roasting zinc silicate using NaOH was investigated. The orthogonal test was employed to optimize the reaction conditions and the optimized reaction conditions were as follows: molar ratio of NaOH to Zn2SiO4 of 16:1, reaction temperature of 550 °C, and reaction time of 2.5 h. In order to ascertain the phases transformation and reaction processes of zinc oxide and silica, the XRD phase analysis was used to analyze the phases of these specimens roasted at different temperatures. The final phases of the specimen roasted at 600 °C were Na2ZnO2, Na4SiO4, Na2ZnSiO4 and NaOH. The reaction kinetic equation of roasting was determined by the shrinking unreacted core model. Aiming to investigate the reaction mechanism, two control models of reaction rate were applied: chemical reaction at the particle surface and diffusion through the product layer. The results indicated that the diffusion through the product layer model described the reaction process well. The apparent activation energy of the roasting was 19.77 kJ/mol.

In this study, cyclohexanol was used as the raw material to replace cyclohexanone during the synthesis of symmetric dicyclohexanocucurbit[6]uril (CyH2Q[6]), which successfully avoided the use of selenium dioxide and greatly improved the yield of cyclohexyl-substituted glycoluril as the intermediate product (96%). In addition, using CyH2Q[6] as the host molecule and glycine (Gly) as the guest, the interaction mode between the two in both an aqueous and solid phase was studied using 1H NMR spectroscopy and X-ray crystallography. Analysis of the 1H NMR spectra and crystal structure showed that CyH2Q[6] and Gly form a 1:2 host–guest inclusion compound.

The binding interactions of CyP6Q[6] with a series of alkyl diammonium (+H3N(CH2)nNH3+, n = 2, 4, 6, 8, 10, 12) and aryl diammonium (p-phenylenediammonium and p-xylenediammonium) ions both in aqueous solution and in the solid state have been studied by 1H NMR spectroscopy, X-ray crystallography, and isothermal titration calorimetry (ITC) techniques. 1H NMR data indicate that all guests exhibit endo binding with CyP6Q[6] except for the ethanediammonium ion, which bound exo to CyP6Q[6]. p-Xylenediammonium ions show mixed behavior (exo and endo binding with CyP6Q[6]). X-ray crystallography clearly displays the extended and contorted conformations of the guests when bound within CyP6Q[6]. The ITC study points out that the CyP6Q[6] complex formations with all guests are mainly driven by enthalpy, which arises from the ion–dipole interactions and the hydrophobic effects.

A new inorganic/organic composite film PEDOT:Ce@TiO2 was prepared through drop casting-secondary polymerization method using the mixture solution of PEDOT oligomer and cerium-containing polyoxotitanate cage [Ti8O7(HOEt)(OEt)21Ce]. PEDOT:Ce@TiO2 exhibits a special nanostructure with gully-like rough surface, which shows strong hydrophobicity while good wettability to acetonitrile solution. PEDOT:Ce@TiO2 can be used as cathodically electrochromic film and supercapacitor electrode material. The mass specific capacitance of PEDOT:Ce@TiO2 is 71.2 F/g at a current density of 1 A/g, which is 1.7 times higher than that of the PEDOT film. An all-solid-state electrochromic supercapacitor prototype device was further assembled using PEDOT:Ce@TiO2. With charging completed the electrochromic area of this device shows dark green, and it turns bright yellow with discharging completed.

In this study, fully substituted cyclopentano cucurbit[5]uril (CyP 5 Q[5]) were coordinated with an alkaline earth cations (AE 2+ ) in the presence of tetrachlorozincate anions ([ZnCl 4 ] 2− ). Single-crystal X-ray diffraction analysis revealed that the CyP 5 Q[5]–Mg 2+ –[ZnCl 4 ] 2− –HCl interaction system yielded an Mg 2+ /Cl − @CyP 5 Q[5]-type molecular bowl, with a chloride anion in the cavity of the CyP 5 Q[5] moiety. The CyP 5 Q[5]–Ca 2+ and Sr 2+ –[ZnCl 4 ] 2− –HCl interaction systems yielded isolated AE 2+ /CyP 5 Q[5]/AE 2+ -type molecular capsules, again with a chloride anion in the CyP 5 Q[5] cavity. A honeycomb effect was evident in all three systems, in which the of the [ZnCl 4 ] 2− anions surround the CyP 5 Q[5] molecules through outer surface interactions between Q[n] and electrostatic interactions with AE 2+ cations, resulting in the formation of porous supramolecular assemblies. Direct coordination between Ba 2+ and CyP 5 Q[5] yielded zigzag coordination polymers. The CyP 5 Q[5]/AE 2+ -based supramolecular assemblies (AE = Mg, Ca, Sr, Ba) presented different porous conformations and displayed differential absorption of volatile compounds.

Coordination of fully substituted cyclopentano cucurbit[5]uril (CyP5Q[5]) with an alkali cation (A+) in the presence of tetrachloridezicate anions was investigated. Single-crystal X-ray diffraction analysis revealed that the CyP5Q[5]–Na+ and K+–[ZnCl4]2−–HCl interaction systems yielded an A+/Cl−@CyP5Q[5]/A+-type molecular capsule, and that a chloride anion was included in the cavity of the CyP5Q[5] molecule. [ZnCl4]2− anions were not involved in direct coordination with the A+/Cl−@CyP5Q[5]/A+ capsule. The CyP5Q[5]–Rb+ and Cs+–[ZnCl4]2−–HCl interaction systems yielded an A+/CyP5Q[5]/A+-type molecular capsule shell, and no chloride anions were included in the cavity of the CyP5Q[5] molecule. [ZnCl4]2− anions directly interacted with coordinated Rb+ or Cs+ cations through electrostatic interaction, and [ZnCl4]2− anions in particular played the role of linkers, resulting in the formation of a linear supramolecular assembly ⋯[ZnCl4]2−–A+/Cl−@CyP5Q[5]/A+–[ZnCl4]2−–A+/Cl−@CyP5Q[5]/A+⋯. Close inspection revealed that the obtained CyP5Q[5]/A+-based supramolecular assemblies (A = Na, K, Rb, Cs) presented different porous conformation and could show different absorption properties.

The interactions between cyclopentanocucurbit[6]uril (abbreviated as CyP6Q[6]) and a series of dialkyl-4,4′-bipyridinium and diaryl-4,4′-bipyridinium dicationic guest molecules, where the alkyl group is CH3(CH2)n with n=0–6 (expressed as G1 to G7) and the aryl group is phenylene (G8) and xylene (G9), have been investigated in aqueous solution using 1H NMR spectroscopy, isothermal titration calorimetry (ITC), and electronic absorption spectroscopy. Our results show that G1 and G2 form 1:1 host–guest inclusion complexes with CyP6Q[6], in which the bipyridinium core is partially embedded in the cavity of CyP6Q[6]. G3–G9 form 2:1 dumbbell-type host–guest inclusion complexes, in which the substituents are encapsulated by CyP6Q[6]. At the same time, CyP6Q[6] was compared with several other cucurbit[n]urils (Q[n]s) and their derivatives, such as Q[6], Q[7], and TMeQ[6], which have been reported to interact with this type of guest molecule. In its binding mode, CyP6Q[6] shows many interesting and different properties, and this difference was mainly reflected with G1 and G2.

Coordination and supramolecular assemblies of a fully substituted cyclopentanocucurbit[6]uril (CyP6Q[6]) with a series of lanthanide cations (Ln3+) have been investigated in the presence of tetrachlorozincate anion ([ZnCl4]2–). X-ray single-crystal diffraction analysis has revealed that the interaction of CyP6Q[6] and a series of Ln3+cations unexpectedly results in the formation of at least seven different CyP6Q[6]-based coordination complex adduct and supramolecular assemblies groups, including with (1) La3+, Ce3+cations; (2) Pr3+, Nd3+cations; (3) Eu3+, Gd3+, Tb3+, Dy3+ with P1 or P1 space group, in which CyP6Q[6] molecules coordinate alternatively with Ln3+cations and form linear coordination polymers; (4) CyP6Q[6] molecules interact alternatively with [Ho(H2O)8]3+ aqueous complexes and form linear supramolecular chains; CyP6Q[6] molecules can assemble two different Ln3+ free porous supramolecular assemblies from CyP6Q[6]–Ln(NO3)3–ZnCl2–HCl systems, Ln = Tm, Yb, and Lu; however, no solid crystals were...

Vanadium battery has fast and large capacity charge and discharge characteristics, and the concentration and stability of the battery electrolyte are the key to the electrolyte performance. In actual, with higher acidity and higher concentration of the vanadium battery electrolyte, the ion-pair is dominant. The ion-pair dissociation constant is one of the important thermodynamic data related to battery performance. The vanadyl sulfate conductivity in aqueous solution was determined using the conductance method at 298.15 K. Using the origin data fitting, the limiting molar conductance is obtained, and then by the improved Ostwald dilution law and the Davies equation, the activity coefficient is solved so as to obtain the ionic strength of the true solution. Using the Fuoss method, the dissociation constant of vanadyl sulfate ion-pair was calculated. At last, the vanadyl sulfate limiting molar conductance (Λ 0 ) is 174.8251748 S·dm2·mol−1, and the vanadyl sulfate ion-pair dissociation constant K d is 0.002636367, and then other thermodynamic properties can be studied.

Kinetics of SiO 2 leaching from Al 2 O 3 extracted slag of fly ash with sodium hydroxide solution was studied. The effect of leaching temperature, mass ratio of NaOH to SiO 2 and stirring speed on SiO 2 leaching rate was investigated. The results show that increasing leaching temperature, mass ratio of NaOH to SiO 2 and stirring speed increases SiO 2 leaching rate. The SiO 2 leaching rate is 95.66% under the optimized conditions. There are two stages for the SiO 2 leaching process, and the leaching reaction is very rapid in the first stage but quite slow in the second stage. The whole leaching process follows the shrinking core model, and the outer diffusion of no product layer is the rate-controlling step. The activation energies of the first and second stages are calculated to be 8.492 kJ/mol and 8.668 kJ/mol, respectively. The kinetic equations of the first and the second stages were obtained, respectively.

NH 4 HSO 4 roasting technology was used for preparing Al 2 O 3 from fly ash. First, Al and Fe were extracted from fly ash by NH 4 HSO 4 roasting and deionized water leaching. Then, the Al and Fe in the leached liquid were precipitated by adding NH 4 HCO 3 solution. After the mixed precipitations of Al(OH) 3 and Fe(OH) 3 were leached by NaOH solution, the NaAl(OH) 4 solution was decomposed by carbonation. Finally, the pure Al(OH) 3 was calcined to α-Al 2 O 3 . The optimal conditions of the whole technology were determined by experiments. The quality of α-Al 2 O 3 product is up to the technical indicator of YS/T 274-1998 standard.

Through the arduous study of the famous Cohen-Sutherland algorithm, this paper proposes a novel improved algorithm by analyzing its main flaw in efficiency. The line segment without the clipping window will be rejected in our algorithm. By means of adding auxiliary straight-line, this algorithm efficiently calculates intersection points between line and the boundary of clipping window. Thus, this improved algorithm is simple, improving its clipping efficiency and reaching the desired results.

Investigations were conducted to purify crude Li2CO3 via direct carbonation with CO2-water solutions at atmospheric pressure. The experiments were carried out in a slurry bubble column reactor with 0.05 m inner diameter and 1.0 m height. Parameters that may affect the dissolution of Li2CO3 in the CO2-water solutions such as CO2-bubble perforation diameter, CO2 partial pressure, CO2 gas flow rate, Li2CO3 particle size, solid concentration in the slurry, reaction temperature, slurry height in the column and so on were investigated. It was found that the increases of CO2 partial pressure, and CO2 flow rate were favorable to the dissolution of Li2CO3, which had the opposite effects with Li2CO3 particle size, solid concentration, slurry height in the column and temperature. On the other hand, in order to get insight into the mechanism of the refining process, reaction kinetics was studied. The results showed that the kinetics of the carbonation process can be properly represented by 1−3(1−X)2/3+2(1–X)=kt+b, and the rate-determining step of this process under the conditions studied was product layer diffusion. Finally, the apparent activation energy of the carbonation reaction was obtained by calculation. This study will provide theoretical basis for the reactor design and the optimization of the process operation.

The crystallization kinetics of Li 2 CO 3 from LiHCO 3 solutions was studied by a non-evaporation volume-constant batch reactor. The factors influencing the crystallization process such as initial concentration, temperature and stirring speed were investigated and discussed. In the experiment, CO 2 was stripped from a slightly acidic solution of LiHCO 3 by stirring resulting in critical supersaturation and precipitation of Li 2 CO 3 . The reduction of the Li + concentration was recorded as a function of time by determination with flame atomic absorption spectrometry (FAAS), and the pH values were also measured. The results showed that the crystallization rate increased and the induction period shortened with increase in the initial concentration and temperature. In addition, high stirring speed could significantly promote this process. Thermodynamic parameters at critical conditions such as the surface free energy and critical radius of nucleus were estimated based on the crystallization theory and experimental results. The results showed that the crystallization kinetics of this process coincided with the second-order reaction rate equation, and the apparent activation energy of the process was obtained. The analysis of the crystal growth mechanism showed that the growth of Li 2 CO 3 from LiHCO 3 solutions was mainly controlled by diffusion.

This paper describes the results from an experimental study of the purification of LiHCO3 solution which is used to produce high-purity Li2CO3 by ion exchange. Generally, there are some amounts of Ca2+ and Mg2+ in the LiHCO3 solution whose contents exceed the requirements to produce qualified high-purity Li2CO3, so they need to be removed from the solution. There are many methods available to remove divalent metal ions from solutions, among which the ion exchange is the most simple and efficient one. Investigations of the performance of the chelating resin Amberlite IRC747 for its adsorption for Ca2+ and Mg2+ in LiHCO3 solutions were conducted. Batch studies showed that the SDM-A model could describe the adsorption isotherm data well, and the Kannan particle diffusion model could describe the exchange kinetics properly. The study for column operation showed that breakthrough points of Ca2+ and Mg2+ both advanced with increasing the feed flow rate, and the penetration function model could describe the effluent curves adequately. HCl and LiOH of 1 mol·L− 1 respectively were used to regenerate resins with good effect. This study will provide the basic reference for process operation and the reactor design to purify the LiHCO3 solution by ion exchange.

The solid-state reaction was employed to obtain LiBOB in vacuum dryer at 100°C, with the dryer of P2O5. The resulting LiBOB was employed in various ternary solvent blends to get the k, and its change with salt, solvent composition and temperature. 0.7 M LiBOB-PC/EMC/DMC (1: 1: 1, v: v: v) and 0.5 M LiBOB-EC/EMC/DMC (1: 1: 1, v: v: v) were observed to have better k at wide θ range, and the former was chosen to assemble Li/MCMB and LiFePO4/Li cells. The results indicated that it can stabilize the MCMB anodes, and exhibit good stability in LiFePO4/Li cell.

Boron removal by ion exchange resin from refined brine which was used to produce low-boron lithium salts was studied. A new boron-specific resin, XSC-800 was used in the experiments for the separation of boron. The column-mode and batch-mode sorption studies were both performed so as to obtain the optimum conditions for boron removal from refined brine. Parameters such as flow rate of brine, boron concentration, temperature, pH, height/diameter (H/D) ratio of the column, anion concentration, stirring speed and diameter of the resin were investigated. The results showed that the removal effect of boron by XSC-800 improved with increasing temperature, pH, H/D ratio, and with decreasing the flow rate of brine, boron concentration, chloride anion concentration and diameter of the resin. While the stirring speed and the recycles of the resin had no significant effects on boron removal. As a result, boron can be removed from refined brine much completely by the resin at the optimum conditions. On the other hand, kinetics of the exchange process was studied by using the moving boundary model. In order to describe the kinetics more accurately, the model was modified by introducing a time correction factor. The results showed that the rate-determining step of this process under the conditions studied was controlled by particle diffusion. In addition, the apparent activation energy Ea of the process was found to be 20.38 kJ/mol.

Refining of crude Li2CO3 produced from salt lake brines of Qinghai, China, by direct carbonation with CO2-water solutions under different conditions was studied. The process is based on the reaction of Li2CO3 with CO2-water solutions to convert the former to the more soluble lithium bicarbonate. The carbonation experiments were carried out in a three-phase mechanically agitated slurry-bed reactor. The parameters that may affect the dissolution of Li2CO3 in CO2-water solution such as CO2 pressure, temperature, CO2 flow rate, solid concentration, particle size of Li2CO3, slurry filling degree, agitator shape and agitation speed were investigated. The effects of immersion time of Li2CO3 in the slurry before carbonation as well as multiple carbonation cycles were also examined. Refining of crude Li2CO3 produced from salt lake brines of Qinghai, China, by direct carbonation with CO2-water solutions under different conditions was studied. The process is based on the reaction of Li2CO3 with CO2-water solutions to convert the former to the more soluble lithium bicarbonate. The carbonation experiments were carried out in a three-phase mechanically agitated slurry-bed reactor. The parameters that may affect the dissolution of Li2CO3 in CO2-water solution such as CO2 pressure, temperature, CO2 flow rate, solid concentration, particle size of Li2CO3, slurry filling degree, agitator shape and agitation speed were investigated. The effects of immersion time of Li2CO3 in the slurry before carbonation as well as multiple carbonation cycles were also examined.

Using TG-FT-IR coupling method, direct evidences of the decomposition process of lithium hexafluorophosphate had been obtained. Studies showed that LiPF6 is stable under normal temperature when the content of water is very low. When heated, LiPF6 would react with the trace water in the air. HF and OPF3 would be released in the same time which could be detected from the FT-IR spectra collected in situ. The peak temperature of the decomposition of LiPF6 varied from 192.93 degrees C (average heating rate 2.0 degrees C min(-1)) to 223.83 degrees C (average heating rate 20.0 degrees C min(-1)). Based on the on-line FT-IR spectra, the characteristic absorption bands of PF6- in the decomposed substances were detected for the first time which might come from the reaction of trace HF with PF5. (c) 2005 Elsevier B.V. All rights reserved. Using TG-FT-IR coupling method, direct evidences of the decomposition process of lithium hexafluorophosphate had been obtained. Studies showed that LiPF6 is stable under normal temperature when the content of water is very low. When heated, LiPF6 would react with the trace water in the air. HF and OPF3 would be released in the same time which could be detected from the FT-IR spectra collected in situ. The peak temperature of the decomposition of LiPF6 varied from 192.93 degrees C (average heating rate 2.0 degrees C min(-1)) to 223.83 degrees C (average heating rate 20.0 degrees C min(-1)). Based on the on-line FT-IR spectra, the characteristic absorption bands of PF6- in the decomposed substances were detected for the first time which might come from the reaction of trace HF with PF5. (c) 2005 Elsevier B.V. All rights reserved.

LiFePO 4 /C and LiFePO 4 /C+Ag samples were prepared by sol-gel method. Samples were characterized by XRD, SEM, EIS and electrochemical discharge and charge tests. Silver modification does not affect the olivine structure of LiFePO 4 but enhances its electrochemical performance in terms of discharge capacity and rate capacity. Discharge capacities are improved from 130.8 mAhg-1 of LiFePO 4 /C to 149.8mAhg-1 of LiFePO 4 /C+Ag cathodes. EIS measurements show that Silver modification slightly decreases the charge transfer resistance of LiFePO 4 /C, and lithium ion diffusion coefficient is enhanced from 2.89×10-14 to 8.17×10-13 m2 s-1. 1 , the phosphor- olivine LiFePO 4 has been recognized as a potential positive electrode material for use in lithium ion batteries. Although LiFePO 4 possesses a number of advantages (high capacity, high stability during lithium extraction/insertion, environmental friendliness, etc) 2 , its main drawback is poor electrochemical performance due to its sluggish charge/discharge kinetics. In order to increase the charge capacity and improve the conductivity, many attempts have been performed, using approaches such as decreasing active particle size 3-5 , carbon coating 6-9 , ion doping 10-12 and surface modification 13-15 etc. Surface modifications are of great importance in developing electrode materials 15 . In the present paper we investigate the role of silver modification in improving the performance of LiFePO 4 , Wherein we took silver mirror reaction to coat each particle with a thin silver coating. Particles are prepared via a sol-gel route using Fe(Ш) citrate as chelating agent. The impacts of silver coating on the electrochemical properties of LiFePO 4 -based cathodes are systematically studied. EXPERIMENT LiFePO 4 /C composites were prepared by a sol-gel method with subsequent firing of xerogel in argon(purity≥99.99%) atmosphere. First, Fe(Ш) citrate(Sigma, Technical Grade) was dissolved at 70°C in deionized water. Second, equimolar aqueous solution of LiH 2 PO 4 was prepared from NH 4 H 2 PO 4 (GR, sinopharm) and Li 2 CO 3 (99.84%, self-made). The solutions were mixed together and the obtained transparent sol was dryed at 70°C for at least 20h after grinding with mortar and pestle for 10min, the obtained material was fired in argon atmosphere at 700 °C for 18h the heating rate being 10K/ min. The surface modification was performed by silver mirror reaction 13-14

In the title compound, C12H17NO3, the conformations of the N—H and C=O bonds areantito each other. In the crystal structure, N—H...O hydrogen-bond interactions help to establish the packing.

The asymmetric unit of the title compound, (C24H26N2)[ZnCl4], consists of two 2,2′-(hexane-1,6-di­yl)diisoquinolinium cations and two [ZnCl4]2− complex anions. The [ZnCl4]2− anions have a distorted tetra­hedral geometry. The dihedral angles between the isoquinoline rings of the two cations are nearly equal [16.1 (2) and 16.3 (2)°]. In the crystal structure, the ordered linear formation is aggregated by weak inter­molecular π–π stacking inter­actions between neighboring isoquinoline pyridine rings with a centroid–centroid distance of 3.779 (4) A.

In the title compound, C(10)H(12)N(8)O(4)·H(2)O, prepared from the reaction of glycoluril with paraformaldehyde, the organic molecule has mm symmetry. The asymmetric unit comprises one quarter of the mol-ecule and a half-mol-ecule of water. The dimer is formed by bridging two glycoluril mol-ecules with methyl-ene groups at the 1 and 6 positions. In the crystal structure, mol-ecules are linked via N-H⋯O and O-H⋯O hydrogen bonds, forming a two-dimensional framework.

Composites Li1−xVxCryFe1−yPO4/C (x = 0.01, 0.02; y = 0.01, 0.02) were synthesized by solid-state reaction method. The influence of the content of doping vanadium and chromium on the structure of Li1−xVxCryFe1−yPO4/C was investigated by XRD, while the morphology of powders was observed by SEM. The investigation of the electrochemical performances showed that the Li0.99V0.01Cr0.02Fe0.98PO4/C material has a higher capacity. At 0.1 C discharging rate, it is capable of delivering reversible specific capacity of 163.8 mAh/g with fairly stable cycleability.

A novel Na specific adsorbent Li(1+x)Al(x)Ti(2-x)(PO4)3 was synthesized by high temperature solid state reaction method. The samples were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM). Raman and FTIR spectroscopic studies of these materials were carried out, and the vibrational bands were assigned. Their adsorption performances were investigated. The results indicate that the low concentration (x0.6) Al dopant does not affect the structure of the material but makes it able to selectively adsorb sodium. The adsorbing test results show that its exchange capacity is high with the maximum value of adsorption capacity of 11.76 mg x g(-1) at x = 0.4 and pH = 10.0-11.0. So it can be used to remove the microamounts impurity-sodium in the production of high purity lithium salt.

In the title compound, C10H12N8O4·H2O, prepared from the reaction of glycoluril with paraformaldehyde, the organic molecule has mm symmetry. The asymmetric unit comprises one quarter of the molecule and a half-molecule of water. The dimer is formed by bridging two glycoluril molecules with methylene groups at the 1 and 6 positions. In the crystal structure, molecules are linked via N—H...O and O—H...O hydrogen bonds, forming a two-dimensional framework.

Three guests with two moiety probes for different Cucurbit[n = 6-8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)-adamataneamine and N-(2-methylenefurfuran)-adamataneamine. The probes are methyle-nepyridyl typically for Q[6] and adamataneamine typically for Q[7]. The host-guest complexes of Cucurbit[n = 6-8]urils with these guests have been investigated by using NMR techniques and ESMS method. Also, thermoanalysis has been used for exploring relationship of enthalpy and stability of the host-guest complexes.