The ε-Complexity of the Approximate Solution of Integral Equations with Isotropic Kernels

The exact order of s-complexity is determined in L_p (2≤p≤∞) spaces for the second kind of Fredholm integral equations with kernels belonging to an isotropic Sobolev class.

Synthesis and Crystal Structure of the Azo Copper(Ⅱ)-complex

The single crystals of the azo copper（Ⅱ）-complex have been obtained from the solution of the compound dissolved in the ethanol by slow evaporation at room temperature. The structure was successfully determined by single-crystal X-ray diffraction. The crystal is of triclinic system, space group P1 with a = 7.8843（12）, b = 11.5998（17）, c = 13.955（2） A, α = 112.214（2）, β = 95.105（2）, γ = 97.616（2）o, V = 1157.6（3） A^3, Mr = 586.97, Z = 2, F（000） = 600, Dc = 1.684 g/cm^3, μ（MoKα） = 1.120 mm-1, the final R = 0.0419 and wR = 0.1259 for 3475 observed reflections with I 〉 2σ（I）. The coordination around copper（II） atom is a slightly distorted square-pyramidal geometry involving [Cu（C16H11N4O8S）（OH）H2O]-cation, one Na＋ anion and one C2H5OH solvate molecule. The hydrogen bonds and π···π stacking interactions extend the complex into a three-dimensional framework.

A Simple Method for Preparing CuCl/Activated Carbon for Selective CO Adsorption from Hydrogen

Carbon monoxide(CO)is an impurity gas that can poison the precious metal catalysts of hydrogen fuel cells,so it is necessary to separate CO from hydrogen.In this paper,an isovolumetric impregnation method was developed to prepare Cu(I)-supported activated carbon(AC),which is simple and easy to industrialize.The prepared cuprous chloride CuCl/AC adsorbent displayed a high CO adsorption capacity of 82.1 cm^(3)/g and a high CO/H_(2) separation factor of 20 at 20 bar and 298 K.This material can adsorb and remove CO from CO/H_(2) mixed gas(5μL/L CO-balanced H_(2))to less than 0.2μL/L under dynamic flow conditions,and showed excellent regeneration performance.The results show that CuCl/AC is an effective adsorbent for separating trace CO in high-purity hydrogen.

Fabrication of adsorbents with enhanced CuⅠ stability: Creating a superhydrophobic microenvironment through grafting octadecylamine

In atmospheric conditions, CuⅠis easily oxidized to CuⅡdue to the coexistence of moisture and oxygen.The poor oxidation inhibition of CuⅠrestricts the practical application of CuⅠ-containing materials.Herein we introduce an approach to construct a superhydrophobic microenvironment in CuⅠfunctionalized metal–organic frameworks by coordinatedly grafting organic amine compounds onto open metal sites(OMSs), which can hinder the accessibility of moisture to pores thereby enhancing the stability of CuⅠ. As a proof of concept, MIL-101(Cr) with abundant OMSs and octadecylamine(OA)with long hydrophobic alkyl groups are used as carrier and surface coating. As superhydrophobic porous materials, the resultant CuⅠM-OA exhibits improved CuⅠstability in addition to retaining high crystallinity and intact porosity while almost all CuⅠis oxidized in hydrophilic CuⅠM upon exposure in a humid atmosphere for 30 h. CuⅠM-OA owns excellent adsorption desulfurization performance(ADS) with regard to thiophene, benzothiophene, and 4,6-dimethyl dibenzothiophene. Even from hydrated fuel, the adsorption performance of CuⅠM-OA maintains well while the adsorption capacity of CuⅠM decreases to 7% after4 cycles. The remarkable moisture resistance, CuⅠstability, and high porosity make the current adsorbent CuⅠM-OA highly promising for the practical ADS process.

2-local unstable homotopy groups of indecomposable A^(2)_(3)-complexes

In this paper,we calculate the 2-local unstable homotopy groups of indecomposable A^(2)_(3)-complexes.The main technique used is analysing the homotopy property of J(A,X),defined by Gray(1973) for a CW-pair(X,A),which is homotopy equivalent to the homotopy fibre of the pinch map X∪CA→∑A.

Removal of carbonyl sulfide from CO_2 stream using AgNO_3-modified NaZSM-5

Removal of carbonyl sulfide(COS) from CO2 stream is significant for the production and utilization of food grade CO2. This study investigates the adsorption performance of Ag/NaZSM-5 as adsorbent prepared by incipient wetness impregnation for the removal of COS from a CO2 stream in a fixed-bed adsorption apparatus. Effects of various conditions on the preparation of adsorbent, adsorption and desorption were intensively examined. The results revealed that COS can be removed to below 1×10-9from a CO2stream(1000 ppm COS/CO2) using Ag/NaZSM-5(10 wt% AgNO3) with an adsorption capacity of 12.86 mg·g-1. The adsorbent can be fully regenerated using hot air at 450 C. The adsorption ability remained stable even after eight cycles of regeneration.

Synthesis and Fluorescence of Eu-Ibuprofenum-Phen Complex and Determination of ATP by Fluorescence Quenching of Complex

The complex Eu(IB)_3(phen)·2H_2O was synthesized. The results show that the strong fluorescence emitting of 593 and 615 nm for Eu^(3+) in the Eu(IB)_3(phen) complex is related to the transitions (()~5D_0-()~7F_1) and (()~5D_0-()~7F_2,) respectively. A sensitive method for the determination of adenosine disodium triphosphate (ATP) by fluorescence quenching is proposed. The method is based on the ability of ATP to inhibit the formation of a strong fluorescent complex of Eu(IB)_3(phen). In conditions of pH 6.7 HAc-NaAc buffer, λ_(ex)=273 nm and λ_(em)=615 nm, the linear range of the determination was 0.1～10 μg·ml^(-1) and the detection limit was 0.03 μg·ml^(-1) for ATP. The method has been applied to determine ATP in adenosine disodium triphosphate tablets samples with relative standard deviation of 2.18% and recovery of (98.4%～)104.0%.

Study on Interaction of La-Enoxacin Complex and Bovine Serum Albumins by Fluorescence

A new complex La(ENX)_3Cl_3·2H_2O was synthesized. The interaction between La-Enoxacin complex and bovine serum albumins (BSA) were studied by fluorescence and UV-Vis absorption spectra. The research results indicate that the combination reaction of them is a single static quenching process, La-Enoxacin complex strongly bound BSA, the equilibrium constant K_0=1.45×107 L·mol -1 (at 25 ℃). The shortest binding distance(r) and energy transfer efficiencies(E) between donor (BSA) and acceptor (La-Enoxacin) obtained by Frster′s nonradiative energy transfer mechanism are as follows, r=4.07 nm, E=0.118. The hydrophobic force plays major role in the reaction.

Spectroscopic Characterization of Eu-Enoxacin-Phen Complexes and Determination of ATP by Fluorescence Quenching

The complex of Eu 3+ and Enoxacin(ENX) and Phen was synthesized. Its compositions is Eu(ENX)_3(phen)Cl_3·2H_2O. Its fluorescence spectra were studied. The results show that the strong fluorescence emitting of 592 and 616 nm for Eu 3+ in the Eu(ENX)_3(phen)Cl_3·2H_2O complex is related to the transitions 5D_0-7F_1 and 5D_0-7F_2 respectively. A sensitive method for the determination of adenosine triphosphate(ATP) by fluorescence quenching is proposed. The method is based on the ability of ATP to inhibit the formation of a strong fluorescent complex of Eu(ENX)_3(phen)Cl_3·2H_2O. In conditions of pH 6.7 in HAc-NaAc buffer and λ_ ex=340 nm and λ_ em=616 nm, the linear range of the determination is 0.4～ 10 μg·ml -1 and the detection limit is 0.034 μg·ml -1 for ATP. The method was applied to determine ATP in adenosine disodium triphosphate injection samples with relative standard deviation of 212% and recovery of 94.8%～1037%.

Fluorescence of Tb-Ibuprofenum-Phen Complex and New Tissue Staining Method

A new complex Tb(IB)_3(phen)·2H_2O that gives off green fluorescence was synthesized. The results show that the strong fluorescence emitting of 490 and 545 nm for Tb 3+ in the Tb(IB)_3(phen)·2H_2O complex is related to the transitions 5D_4-7F_6 and 5D_4-7F_5, respectively. The results indicate that the complex is concentrated on the nuclei regions in the section of onion toot tip tissues and the nuclei are high lighted under fluorescent microscope. It is possible that the Tb(IB)_3(phen)·2H_2O complex can be developed as a fluorescent dye in biological and pathological studies.

Synthesis and Crystal Structure of a Dinuclear Compound Cu_2[(O=PPh_2)_2N]_2(μ-O_2PPh_2)_2

A neutral dinuclear compound Cu2[（O=PPh2）2N]2（μ-O2PPh2）2 has been unexpectedly prepared from the reaction of [Cu2（dppa）2（MeCN）4]（ClO4）2 （dppa = bis（diphenylphosphino）- amine） and Sn（edt）2（edt = ethane-1,2-dithiolate） in dichloromethane in air. ESR spectrum shows that the original Cu^＋ ion has been oxidized. The crystal structure determined by an X-ray single diffractometer displays that the concurrence of the redox and hydrolysis of the origin ligand dppa is taken with the formation of two new ligands. The complex crystallizes in triclinic, space group P1^- with a = 9.4269（13）, b = 10.7522（13）, c = 16.787（2）A^°, α= 92.042（5）, β= 104.591（7）, γ = 96.167（6）°, V= 1633.6（4） A^°3, C72H60 Cu2N2O8P6, Mr = 1394.12, Z = 1, D,. = 1.419 g/cm^3, F（000） = 718,μ = 0.856 mm^-1, the final R = 0.0530 and wR = 0.1096 for 4210 observed reflections with I 〉 2σ（I）.

Study on Modified Y Zeolites and Their Behaviors in Selective Adsorptive Desulfurization of FCC Gasoline(Ⅱ)

Ce （III） Y zeolite was prepared by liquid-phase ion-exchange of NaY with 0.1 mol/L Ce（NO3）3 solution at 100℃ for 4 h. After calcining the resultant Ce （III） Y zeolite at 550 ℃ in air, Ce （IV） Y zeolite was obtained. Desulfurization of FCC gasoline was studied by selective adsorption with Ce （IV） Y zeolite. The results showed that Ce （IV） Y zeolite can remove thiophene via 0-complexation directly, while thiophene and Ce （IV） can form stable chemical bonds （sulfur-metal bonds） that can enhance the capability of Ce （IV） Y zeolite for adsorption of thiophene.

Photodynamics of Ga_(Zn)–V_(Zn) complex defect in Ga-doped ZnO

The wide-band-gap II–VI compound semiconductor ZnO is regarded as a promising single-photon emission(SPE)host material.In this work,we demonstrate that a(Ga_(Zn)–V_(Zn))^(-)complex defect can readily be obtained and the density can be controlled in a certain range.In analogy to nitrogen vacancy centers,such a defect in ZnO is expected to be a new single photon source.The optical properties of the(Ga_(Zn)–V_(Zn))^(-)complex defect are further studied by photoluminescence and time-resolved photoluminescence spectra measurements.The electron transitions between the defect levels emit light at~650 nm with a lifetime of 10–20 nanoseconds,indicating a good coherent length for SPE.Finally,a two-level emitter structure is proposed to explain the carrier dynamics.We believe that the photodynamics study of the(Ga_(Zn)–V_(Zn))^(-)complex defect in this work is important for ZnO-based quantum emitters.

Zeolites for the separation of ethylene,ethane,and ethyne

The cost-effective separation of ethylene(C_(2)H_(4)),ethyne(C_(2)H_(2)),and ethane(C_(2)H_(6))poses a significant challenge in the contemporary chemical industry.In contrast to the energy-intensive high-pressure cryogenic distillation process,zeolite-based adsorptive separation offers a low-energy alternative.This review provides a concise overview of recent advancements in the adsorptive separation of C_(2)H_(4),C_(2)H_(2),and C_(2)H_(6)using zeolites or zeolite-based adsorbents.It commences with an examination of the industrial significance of these compounds and the associated separation challenges.Subsequently,it systematically examines the utilization of various types of zeolites with diverse cationic species in such separation processes.And then it explores how different zeolitic structures impact adsorption and separation capabilities,considering principles such as cation-πinteraction,π-complexation,and steric separation concerning C_(2)H_(4),C_(2)H_(2),and C_(2)H_(6)molecules.Furthermore,it discusses methods to enhance the separation performance of zeolites and zeolite-based adsorbents,encompassing structural design,modifications,and ion exchange processes.Finally,it summarizes current research trends and future directions,highlighting the potential application value of zeolitic materials in the field of C_(2)H_(4),C_(2)H_(2),and C_(2)H_(6)separation and offering recommendations for further investigation.

Probing the dynamic thermodynamic resolution and biological activity of Cu(Ⅱ) and Pd(Ⅱ) complexes with Schiff base ligand derived from proline

Schiff base metal complexes are of great importance in pharmaceutical science owing to their unique chemical properties, which enable them to exhibit diverse biological activities such as anti-bacterial,anti-oxidant, anti-inflammatory, and anti-tumor properties. Furthermore, Schiff base metal complexes can serve as reagents and catalysts in chemical reactions. This review aims to provide an overview of our recently published studies on Cu(Ⅱ) and Pd(Ⅱ) complexes derived from proline Schiff base ligands. We also discuss the potential applications of these metal complexes in the fields of antibacterial and chiral resolution.

Mechanism of 1,2-shift through π-complex transition state

A systematic calculation of the potential curves or surfaces for 1,2-shift has been realized by using MNDO or other models in MOPAC programs. By referring to the previous author’ viewpoints, the 1,2-shift can be divided into two categories. 1,2-electron-deficient shift is that the electronic configuration of the atom which accepts the migrating group is a cation or an electron-deficient atom, and 1,2-anion shift is the one that the accepted atom of the migration group is a negative ion. In terms of the experimental facts and the calculation of the potential surfaces, in electron-deficient shift such as Beckmann or Baeyer-Villiger rearrangement, the migration occurs through a transition complex formed between the π-bond and the cation or electron-deficient migrating group, but in anion shift such as Wittig or Stevens rearrangement, the electron pair in π-orbit excites at first to π orbit, and then the migration occurs through the new formed complex between the anion migration group and the vacant π orbit. The above mechanisms explain reasonably the intramolecular properties, the configuration retentions of the migration group, and the corresponding migratory aptitudes of the two type 1, 2-shifts. The partial and less important free radical reaction of 1, 2-anion shift has been explained by the π-complex mechanism too.

Separation of C6-Olefin Isomers in Reactive Extractants

Chemical complexation, in which certain metal ions （especially Ag^＋ and Cu^＋） reversibly and selectively complex olefin isomers, was used to separate 1-hexene from a mixture of internal hexenes as an attractive alternative to traditional distillation. Several potential reactive extractants were investigated for their selectivity of both 1-hexene to 2-hexene and 1-hexene to 3-hexene. With 3 mol/L AgNO3-N-methyl-pyrrolidone （NMP） solution as extractant, the selectivity of 1-hexene to 3-hexane was increased to about 2.0 and the selectivity of 1-hexene to 2-hexene reached 1.5. Both the raffinate phase and the extracted phase were analyzed using a gas chromatograph equipped with a flame ionization detector and a 50-m capillary column. The experimental results show that the silver nitrate NMP solution has the better selectivity than other reactive extractions.

Degradation of benzene derivatives in the CuMgFe-LDO/persulfate system:The role of the interaction between the catalyst and target pollutants

A novel insight on the role of interactions between target pollutants and the catalyst in the copper-containing layered double oxide(LDO)-catalyzed persulfate(PS)system was elucidated in the present study.4-Chlorophenol(4-CP),as a representative benzene derivative with a hydroxyl group,was completely removed within 5 min,which was much faster than the reaction of monochlorobenzene(MCB)without a hydroxyl group,with the degradation efficiency of 31.7%in 240 min.Through the use of radical quenching and surface inhibition experiments,it could be concluded that the interaction between 4-CP and CuMgFe-LDO,rather than free radicals,played a key role in the decomposition of 4-CP,while only the free radicals participated in the MCB degradation process.According to electron paramagnetic resonance and Xray photoelectron spectroscopy data,the formation of a Cu(II)-complex between phenolic hydroxyl groups and surface Cu(II)was primarily responsible for the degradation of phenolic compounds,in which PS accepted one electron from the complex and generated sulfate radicals and chelated radical cations.The chelated radical cations transferred one electron to Cu(Ⅱ)followed by Cu(I)generation and pollutant degradation successively.

Atroposelective sp3 C—H Coupling for Kinetic Resolution of Thioanilide Atropisomers

A highly efficient kinetic resolution of racemic thioanilide atropisomers via C(sp^(3))-H arylation has been achieved by a hybrid palladium catalyst bearing an anionic chiral Co^(Ⅲ)-complex and a phosphoramidite ligand,leading to both enantioenriched atropisomeric arylation thioanilides(up to 99%ee)and N-Me atropisomeric thioanilides(up to 99%ee),simultaneously.The remained enantioenriched substrates can be arylated again by using an achiral anionic ligand to give the enantiomer with the opposite configuration.

Asymmetric Synthesis of Chiral Trifluoromethyl Containing Heterocyclic Amino Acids

An operationally convenient, asymmetric synthesis of cbiral trifluoromethyl containing heterocyclic amino ac- ids has been developed via Michael addition reaction of chiral equivalent of Ni（II）-complex of glycine and ]Ltrifluoromethylated-α,β-unsaturated ketones. The simplicity of the experimental procedures and high stereochem- ical outcome of the presented method render these heterocyclic amino acids readily available for systematic medicinal chemistry studies and de novo peptide design.