Synthesis, Spectroscopic and Electrochemical Investigations of Two vic-Dioximes and Their Mononuclear Ni（Ⅱ）, Cu（Ⅱ） and Co（Ⅱ） Metal Complexes Containing Morpholine Group

Two vic-dioxime ligands （LxH2） containing morpholine group have been synthesized from 4-[2-（dimethylaminoethyl）] morpholine with anti-phenylchloroglyoxime or anti-monochloroglyoxime in absolute THF at -15 ℃. Reaction of two vic-dioxime ligands with MCl2·nH2O （M： Ni, Cu or Co and n=2 or 6） salts in 1 ： 2 molar ratio afforded metal complexes of type [M（LxH）2] or [M（LxH）2·2H2O]. All of metal complexes are non-electrolytes as shown by their molar conductivities （Am） in DMF （dimethyl formamide） at 10^-3 mol·L^-1. Structures of the ligands and metal complexes have been solved by elemental analyses, FT-IR, UV-Vis, ^1H NMR and ^13C NMR, magnetic susceptibility measurements, molar conductivity measurements. Furthermore, redox properties of the metal complexes were investigated by cyclic voltammetry.     

Hyperbranched Poly（amide-ester） Mildly Synthesized and Its Characterization

AB2-type-prepolymerized monomer was rapidly （2 h） prepared at room temperature （25 ℃） using commercially available maleic anhydride （MA） and diethanolamine （DEA） as raw materials. By employing toluene-p-sulfonic acid as a catalyzer, a series of hyperbranched poly（amide-ester） （HBPAE） were successfully synthesized from prepared AB2 monomer by solution condensation polymerization through ＂one-step process＂ or ＂pseudo one-step process＂ （using pentaerythritol as a center core）. The processes were carried out at high temperature of 120 ℃ for 6 h in air atmosphere （inert protection free） with reduced pressure distillation （0.08--0.096 MPa）. The results of FT-IR, UV-Vis, TGA, and intrinsic viscosity testing by Ubbelodhe viscometer showed that the prepared HBPAEs possess three-dimensional configuration with unsaturated conjugate structure, large numbers of branches and numerous terminal hydroxyl groups. These result in their low viscosity, high solubility and thermal stability.     

Effect of Mn（Ⅱ） and Ce（Ⅳ） Ions on the Oxidation of Lactic Acid by Chromic Acid

The kinetics and mechanism of lactic acid oxidation in the presence of Mn（Ⅱ） and Ce（Ⅳ） ions by chromic acid were studied spectrophotometrically. The oxidation of lactic acid by Cr（Ⅵ） was found to proceed in two measurable steps, both of which gave pyruvic acid as the primary product in the absence of Mn（Ⅱ）.2Cr（Ⅵ）＋2CH3CHOHCOOH→2CH3COCOOH＋Cr（Ⅴ）＋C（Ⅲ） Cr（V）＋CH3CHOHCOOH→Cr（Ⅲ）＋CH3COCOOHThe observed kinetics was explained due to the catalytic and inhibitory effects of Mn（Ⅱ） and Ce（Ⅳ） on the lactic acid oxidation by Cr（Ⅵ）. The reactivity of lactic acid depends upon the experimental conditions. It acts as a two- or three- equivalent reducing agent in the absence or presence of Mn（Ⅱ）. It was examined that Cr（Ⅲ） products resulting from the direct reduction of Cr（Ⅵ） by three-equivalent reducing agents. The oxidation of lactic acid follows the complex order kinetics with respect to [lactic acid]. The activation parameters Eo, △H^#, and AS^# were calculated and discussed.     

Thermochemistry on the Complex of Erbium Perchlorate with L-α-Glutamic Acid [Er2（L-Glu）2（H2O）6]（ClO4）4·6H2O（s）

A coordination compound of erbium perchlorate with L-α-glutamic acid, [Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）, was synthesized. By chemical analysis, elemental analysis, FTIR, TG/DTG, and comparison with relevant literatures, its chemical composition and structure were established. The mechanism of thermal decomposition of the complex was deduced on the basis of the TG/DTG analysis. Low-temperature heat capacities were measured by a precision automated adiabatic calorimeter from 78 to 318 K. An endothermic peak in the heat capacity curve was observed over the temperature region of 290-318 K, which was ascribed to a solid-to-solid phase transition. The temperature Ttrans, the enthalpy △transHm and the entropy △transSm of the phase transition for the compound were determined to be： （308.73±0.45） K, （10.49±0.05） kJ·mol^-1 and （33.9±0.2） J·K^-1·mol^-1. Polynomial equation of heat capacities as a function of the temperature in the region of 78-290 K was fitted by the least square method. Standard molar enthalpies of dissolution of the mixture [2ErCl3·6H2O（s）＋2L-Glu（s）＋6NaClO4·H2O（s）] and the mixture {[Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）＋6NaCl（s）} in 100 mL of 2 mol·dm^-3 HClO4 as calorimetric solvent, and {2HClO4（1）} in the solution A＇ at T=298.15 K were measured to be, △dHm,1=（31.552±0.026） kJ·mol^-1, △dHm,2 = （41.302±0.034） kJ·mol^-1, and △dHm,3 = （ 14.986 ± 0.064） kJ·mol^-1, respectively. In accordance with Hess law, the standard molar enthalpy of formation of the complex was determined as △fHm-=-（7551.0±2.4） kJ·mol^-1 by using an isoperibol solution-reaction calorimeter and designing a thermochemical cycle.     

Pyrolysis Mechanism of Hemicellulose Monosaccharides in Different Catalytic Processes

The pyrolysis behaviors of four different hemicellulose monosaccharides, namely, two pentoses（xylose and arabinose） and two hexoses（mannose and galactose） catalyzed by HZSM-5 were investigated. The effects of two different processes by which the catalyst comes into contact with the substrate, namely, mixed with monosaccha- ride（in-bed） or layered above monosaccharide（in situ）, were compared. Evolution characteristics of typical pyrolytic products（H20, CO2, acids, furans and aromatics） were achieved by thermogravimetry-Fourier transform infrared spectroscopy. The in-bed catalytic process significantly lowered the pyrolytic temperature and increased the produc- tion of furans and acids at a low temperature by enhancing dehydration, retro-aldol fragmentation and Grob fragmen- tation. During the in situ catalytic process, volatiles generated from monosaccharides passed through a catalyst bed and underwent further dehydration, decarboxylation, and decarbonylation, significantly lowering the yields of acids and furans. The yield of aromatics was enhanced, and the corresponding volatilization temperature was lowered, es- pecially under the in-bed catalytic conditions. Pentoses entered into the zeolite pores more easily than hexoses did because of their smaller molecular size; thus, the in-bed catalytic process drastically affected pentose pyrolysis.     

Construction of a Novel 2D Polymer [Co（dmpzm）（dca）2]∞ from Reaction of a Mononuclear Complex [Co（dmpzm）Cl2] with Sodium Dicyanamide （dca） [dmpzm=bis（3,5-dimethylpyrazolyl）methane]

Reaction of COC12.6H20 with equimolar bis（3,5-dimethylpyrazolyl）methane （dmpzm） produced a mononuclear adduct [Co（dmpzm）Cl2] （1）. Treatment of 1 with sodium dicyanamide （dca） afforded a polymeric complex [Co（dmpzm）（μ-dca）2]∞ （2）. 1 and 2 were characterized by elemental analysis, IR spectra, thermogravimetric analysis and single-crystal X-ray diffraction. The cobalt atom in 1 adopts a distorted tetrahedral coordination geometry, bound to two N atoms of one dmpzm and two Cl atoms. Complex 2 has a 2D brick-wall network （extended along the bc plane） in which the { [Co（dmpzm）（μ-dca）]2} n^2n＋ chains are interconnected by pairs of μ-dca anions along the c axis. The magnetic properties of 1 and 2 were also investigated.     

Electron microscopic observation and rotational diffusion measurement of bacteriorhodopsin in lipid vesicles

The morphology of bacteriorhodopsin reconstituted into dimyristoylphosphatidylcholine and egg-phosphatidylcholine vesicles was observed by freeze-fracture electron microscopy. The rotational diffusion of bacteriorhodopsin at different concentrations of melittin was measured by observing flash-induced transient dichroism in dimyristoylphosphatidylcholine vesicles. In the presence of melittin, bacteriorhodopsin molecules in dimyristoylphosphatidylcholine vesicles were aggregated into large particles or patches, and the ability of rotational diffusion of bacteriorhodopsin in vesicles was decreased. This suggests that melittin produces its effect via direct electrostatic interaction with bacteriorhodopsin. Low temperature-induced aggregation of bacteriorhodopsin was also observed in dimyristoylphosphatidylcholine vesicles. Low temperature may cause phase separation. Bacteriorhodopsin was also successfully reconstituted into egg-phosphatidylcholine vesicles, but low temperature-induced aggregation of bacteriorhod     

Synthesis and X-ray Structural Studies of 2-（2-Benzofuroylimino）-3-aryl-4-phenyl- 1,3-thiazolines

The synthesis for acyliminothiazolines by treatment of N, N□-substituted thioureas with α-bromoacetophenone under aqueous media was described. 2-（2-Benzofuroylimino）-3-aryl- 4-phenyl-1,3- thiazolines were characterized by infrared, NMR spectroscopy and elemental analysis. The single crystals of compounds 4a and 4b were grown by slow evaporation of 80% ethanol solution at room temperature. Compounds 4a and 4b crystallize in triclinic space group P1 and monoclinic space group P21/c, respectively.     

Complete Oxidation of Methane Alumina Modified with Calcium, over Palladium Supported on Lanthanum, and Cerium Ions

The activity and thermal stability of Pd/Al2O3 and Pd/（Al2O3＋MOx） （M=Ca, La, Ce） palladium catalysts in the reaction of complete oxidation of methane are presented in this study. The catalyst supports were prepared by sol-gel method and they were dried either conventionally or with supercritical carbon dioxide. Then they were impregnated with palladium nitrate solution. The catalysts with unmodified alumina had a high surface area. The activity and thermal stability of the aluminasupported catalyst was also very high. The introduction of calcium, lanthanum, or cerium oxide into alumina support caused a decrease of the surface area in the way dependent on the support precursor drying method. These modifiers decreased the activity of palladium catalysts, and they required higher temperatures for the complete oxidation of methane than unmodified Pd/Al2O3. The improvement of the palladium activity by lanthanum and cerium support modifier was observed only at low temperatures of the reaction.     

Mechanism of the Selective Catalytic Reduction of NOx with NH3 over W-Doped Fe/TiO2 Catalyst

The W-doped Fe/TiO2 catalyst prepared by an impregnation method exhibited a good NH3-selective cata- lytic reduction（SCR） activity and N2 selectivity with broad operation temperature window. The interaction between Fe and W could increase the amount of surface chemisorbed oxygen, and thus enhances the low temperature SCR activity by facilitating the fast SCR of 2NH3＋NO＋NO2 →2N2＋3H2O. The NH3-SCR reaction mechanism over the W-Fe/TiO2 was fully investigated via in situ diffuse reflectance infrared Fourier transform spectroscopy（in situ DRIFTS）. In the low temperature range（〈250 ℃）, the reactive surface species were mainly coordinated NH3, ionic NH~ and adsorbed NO2 species, and the SCR mainly followed the Langmuir-Hinshelwood mechanism, during which the adsorbed NO2 species became the important active sites. In the high temperature range（〉250 ℃）, the reactive surface species were mainly NH2, and the SCR mainly followed the Eley-Rideal mechanism, during which the for- mation of NH2NO intermediate species after H-abstraction of NH3 was the rate-determining step.     

INFLUENCE OF PREPARATION CONDITIONS ON THE DISPERSION AND DISTRIBUTION OF NICKEL SPECIES AND ON THE BEHAVIOR OF LOW MICKEL LOADING Ni/Al_2O_3 CATALYSTS

A series of low nickel loading catalysts were prepared by varying theimpregnation conditions before calcination,and characterized by CO methana-tion,XRD,surface area measurement and temperature programmed reductionmethds.It was found that the methanation activity decreased with increasingimpregnation time in excess of 24 h,but the pretreatment of the support byevacuation at room temperature enhanced the activity evidently,which was at-tributed to the formation of highly dispersed nickel species that could be reducedat relatively low temperature.Heating with or without evacuation also alteredthe activity due to the change in distribution of nickel species.     

Preparation and Application of a Nanocomposite （MPNS/SMA） Leather Making

A nanocomposite of MPNS/（Styrene-maleic anhydride） was prepared by the polymerization of methacryloxypropyl nano SiO2 （MPNS）, styrene （ST） and maleic anhydride （MA） with benzoyl peroxide （BPO） as initiator in toluene. The prepared samples were characterized by Fourier transform infrared spectroscopy （PT-IR） and transmission electron microscope （TEM）. Meanwhile, the nanocomposite was applied as a tanning agent in leather making and the results showed that leather treated with MPNS/SMA nanocomposite has excellent quality.     

Zn_xCd_(1-x)S量子点组成与其光催化活性的关系（英文）

Aqueous colloidal dispersions containing Znx Cd1‐x S quantum dots (QDs) of different x compositions were prepared by precipitating zinc and cadmium acetates with sodium sulphide,in the presence of a cetyltrimethylammonium bromide stabilizer.Ultraviolet‐visible absorption spectroscopy was used to determine the transition energies of the QDs,which in turn were used to calculate their sizes,which depended on their composition.The QD size decreased with increasing Zn content.The photocatalytic activity of the Znx Cd1‐x S QDs was studied by the decomposition of methylene blue under ultraviolet irradiation,at a maximum intensity at 365 nm (3.4 e V).Three different photo‐catalytic activity regions were observed,which depended on the Zn content.The quantum levels of the QDs could be excited by incident irradiation,and influenced the resulting photocatalytic activity.Maximum photocatalytic activity was achieved at x = 0.6,where the QD transition energy was equal to the irradiation photon energy.The photocatalytic efficiency of the QDs depended on their surface area and arrangement of quantum levels,because of the quantum size effect.     

Grafting of Poly（lauryl acrylate） onto Nano-silica by ‘Click Chemistry’

Poly（n-alkyl acrylate） with long side groups,namely,poly（lauryl acrylate）（PLA） was synthesized by reversible addition-fragmentation chain transfer（RAFT） polymerization,and the trithioester terminal groups were converted to thiol by reducing reaction.Grafting of the obtained polymer onto nano-silica modified with 3-（methacryloxy）propyl-trimethoxysilane（SiO2-MPS） was conducted by thiol-ene ‘click chemistry＇.PLA was characterized by proton nuclear magnetic resonance（1H NMR） and gel permeation chromatography（GPC）.Fourier transform infrared（FTIR） spectrometry and thermogravimetric analysis（TGA） were used to demonstrate the grafting reaction,and the grafted hairy nano-silica（SiO2-g-PLA） was viewed under a transmission electron microscope（TEM）.According to TGA,grafting ratio and grafting density of SiO2-g-PLA are 30.27％ and 0.013 chain/nm2,respectively.The static water contact angle of SiO2-g-PLA is （80.10±2.97）°,which ensures its hydrophobicity.Dispersion experiment was carried out to confirm its dispersibility in mixed solvents,indicating its potential application in coatings or composites.     

The effects of surface ligands and counter cations on the stability of anionic thiolated M12Ag32 （M=Au,Ag） nanoclusters

The stabilities of [M12Ag32（SR）30]4- （M = Ag, Au and SR = SPhF2, SPhCF3, SPhF） clusters having the same structure but different surface ligands or counter cations were systematically studied. It was clearly revealed that a subtle structural change in the surface ligands or counter cations could significantly alter the overall stability of [M12Ag32（SR）30]4 although they all had an electronic structure of 18-electron superatom shell closure. SPhF2 was found as a better surface ligand than SPhCF3 or SPhF to stabilize [M12Ag32（SR）30]4-. And the use of more bulky [（PPhj）2N]＋ as the counter cations was revealed to be more deleterious to the overall stability of [M12Ag32（SR）30]4- clusters than PPh4＋. [Au12Ag32（SR）30]4- was much more stable than [Ag44（SR）30]4 with the same surface ligands and counter cations. An exceptional stability was observed on （PPh4）4[Au12Ag32（SPhF2）30] which was stable in DMF for more than 8 days in air at 80 ℃. More research efforts are still needed to deeply understand why a small structural change could result in a significant change in the stability of noble metal nanoclusters.     

A mixed-valent high spin(μ-hydroxo)dicobalt(Ⅱ/Ⅲ) complex and its end-on type dioxygen adduct: synthesis,geometric and electronic structure studies

A mixed-valent high spin (μ-hydroxo)dicobalt(Ⅱ/Ⅲ) complex bearing N,N′-bis(5-tertbutylsalicylidene)-1,2-diaminobenzene(Salophen~(t Bu)) ligand was synthesized by reacting (Salophen~(t Bu))Co(Ⅱ)(Py) with O_2 at low temperature.This complex was isolated and structurally characterized by single crystal X-ray diffraction and infrared spectrum.Magnetic measurement showed a quartet ground state for this complex at room temperature,which was also supported by electron paramagnetic resonance (EPR)characterization.Computational investigations indicated the deviation of the equatorial N_2O_2 coordination geometry around the Co(Ⅱ) center from plane stabilized the quartet state.The end-on type O_2 adduct of this (μ-hydroxo)dicobalt(Ⅱ/Ⅲ) complex was isolated as dark-brown crystals and structurally and spectroscopically characterized.EPR measurement of this compound in solid state at room temperature presented an isotropic singlet at g～2,revealing the superoxide-like electronic feature of the coordinated O_2 and was in line with the calculation results.The reactivity of the Co(ⅡI)-O_2 complex with N-hydroxyphthalimide,which can act as hydrogen atom donor,was also examined.     

Synthesis and Crystal Structure of Di-μ1,1-azido-bis（（azido）[N-ethyl-N＇-（1-pyridin-2-ylmethylidene）ethane-1,2-diamino]cadmium（Ⅱ））

The dinuclear Schiff base cadmium（Ⅱ） complex [Cd2（C10H15N3）2（N3）2 （μ1,1-N3）2] was prepared and characterized by elemental analysis, IR spectrum, and single-crystal X-ray dif- fraction. The crystal belongs to the monoclinic system, space group P21/n with a = 10.819（2）, b = 11.058（2）, c = 12.766（3）A, β = 102.456（2）°, V = 1491.3（7）A^3, Z = 2, Dc = 1.665 g/cm^3, Mr = 747.42, λ（MoKα） = 0.71073 （A）, μ = 1.470 mm^-1, F（000） = 744, R = 0.0307 and wR = 0.0584. A total of 3420 unique reflections were collected, of which 2575 with Ⅰ 〉 2σ（Ⅰ） were observed. There is a crystallographic inversion centre at the midpoint of the two metal atoms in the complex. Each CdⅡ atom in the complex is in a distorted octahedral coordination. The molecules in the crystal are linked through the intermolecular hydrogen bonds of N-H…N and C-H…N, forming a three- dimensional network.     

Crystal Structure, Thermal Stability and Luminescence of Coordination Polymer [Cd（BBP）（p-PDOA）]n

Hydrothermal reaction of Cd（NO3）2·4H2O with bbp and p-PDOAH2 at 140 ℃ yielded a novel 1D cadmium（Ⅱ） coordination polymer, [Cd（bbp）（p-PDOA）]n （bbp=2,6-bis（benzimidazol-2-yl）pyridine, p-PDOA=p-phenylenedioxydiacetate dianion）, in which CdN3O4 pentagonal bipyramids were linked by p-PDOA ligands in a bis-bidentate mode to construct a zigzag chain with the adjacent Cd…Cd distance of 1.14（1） nm, There exists a 2D supramolecular network linked by π-π stacking with a face-to-face distance of 0.35（1） nm between the 2,6-bis（benzimidazol-2-yl） pyridine ligands and hydrogen-bonding interactions （0.27（4） nm）. A 3D supramolecular network was further constructed by these non-covalent interactions between the zippers. The TG/DTG showed that its chain skeleton was thermally stable up to 389 ℃ and the blue fluorescent emission of the complex was determined at 428 nm in a solid state with its long decay lifetime of 7.24 ns.     

Synthesis and Crystal Structure of a Novel Tetranuclear Zinc（Ⅱ） Coordination Polymer [Zn4（o-bda）4（p-pbim）4]n

A novel tetranuclear zinc（H） coordination polymer [Zn4（o-bda）a（p-pbim）4]n 1 （p-pbim = 4-pyridylbenzimidazole, o-bda2 = o-phenylenediacetic acid dianion） has been synthesized by a hydrothermal method and characterized by elemental analysis, IR and X-ray singlecrystal diffraction. The title complex crystallizes in monoclinic, space group of P21/n with α = 14.231（1）, b = 16.257（1）, c = 16.794（1） ]k, β = 100.26（1）°, V = 3823.1（2）A3, Z = 8, Dc = 1.573 g/cm^3,β = 1.321 mm^-1, F（000） = 1856, R = 0.0420 and wR = 0.111. The Zn（1） atom assumes a distorted trigonal bipyramidal geometry, involving three carboxyl O atoms from two different o-bda ligands and two N atoms from two p-pbim ligands. The Zn（2） atom is coordinated by two oxygens from two distinct bda2- anions and two nitrogen atoms from two p-pbim ligands to form a distorted tetrahedral geometry. The Zn（Ⅱ） atoms are alternately interlinked by o-bda ligands in bis-monodentate or chelating-bidentate and monodentate modes into one-dimensional undulate chains along axis c with the adjacent Zn…Zn distances of 8.32 and 8.47 A. Such neighboring chains are further extended into a 1D bi-chain structure with two different subrings A and B, which are 32- and 14-membered rings through interchain p-pbim ligands. There exists a 2D supramolecular network linked by intermolecular hydrogen-bonding interactions between the uncoordinated carboxylate 0（4） atom or coordinated carboxylate 0（7） atom and the uncoordinated imidazolyl N（2） and N（5） atoms with the O...N distances to be 2.695 and 2.807A.     

Synthesis of Cu_2O nanobelts via surfactant-assisted polyol method

The synthesis of nanostructured Cu₂O was conducted in a non-aqueous solution via polyol method at a temperature of 130℃.It was found that the formation of Cu₂O nanobelts was heavily dependent on the presence of surfactant cetyltrimethylammonium bromide（CTAB）.Cu₂O nanobelts with 100-400 nm in width and several micrometers in length were only observed when CTAB was used,whereas in other cases where CTAB was absent or CTAB was replaced with polyvinylpyrrolidone（PVP K-30）,only spherical or cube-like particles were formed.The formation mechanism of Cu₂O nanobelts was discussed.