Novel Ni/CeO2-Al2O3 composite catalysts synthesized by one-step citric acid complex and their performance in catalytic partial oxidation of methane

A series of novel Ni/CeO2-Al2O3composite catalysts were synthesized by one-step citric acid complex method. The as-synthesized catalysts were characterized by N2physical adsorption/desorption, X-ray diffraction(XRD), Fourier transform infrared(FT-IR) spectroscopy, hydrogen temperature-programmed reduction(H2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry analysis(TGA). The effects of nickel content, calcination and reaction temperatures, gas hourly space velocity(GHSV) and inert gas dilution of N2on their performance of catalytic partial oxidation of methane(CPOM) were investigated. Catalytic activity test results show that the highest methane conversion(85%), the best selectivities to carbon monoxide(87%) and to hydrogen(95%), the excellent stability and perfect H2/CO ratio(2.0) can be obtained over Ni/CeO2-Al2O3with 8 wt% Ni content calcined at 700 ℃ under the reaction condition of 750 ℃, CH4/O2ratio of 2 : 1 and gas hourly space velocity of 12000 mL h-1 g-1. Characterization results show that the good catalytic performance of this composite catalyst can be contributed to its large specific surface area(～108 m2 g-1), small crystallite size, easy reducibility and low coking rate.     

Nitrogen doped carbon catalyzing acetylene conversion to vinyl chloride

Commercial production of vinyl chloride from acetylene relies on the use of HgCl2as the catalyst, which has caused severe environmental problem and threats to human health because of its toxicity. Therefore, it is vital to explore alternative catalysts without mercury. We report here that N-doped carbon can catalyze directly transformation of acetylene to vinyl chloride. Particularly, N-doped high surface area mesoporous carbon exhibits a rather high activity with the acetylene conversion reaching 77% and vinyl chloride selectivity above 98% at a space velocity of 1.0 mL min-1 g-1and 200 ℃. It delivers a stable performance within a test period of 100 h and no obvious deactivation is observed,demonstrating potentials to substitute the notoriously toxic mercuric chloride catalyst.     

Synthesis and characterization of Bi-functional photorefractive polymers with high molecular weight and low glass transition temperature

Carbazole-based bi-functional photorefractive polyacrylates were prepared via free radical polymerization and post-azo-coupling reaction. The structure of polymers was characterized by Fourier transform infrared spectroscopy(FTIR) and proton nuclear magnetic resonance(1H-NMR) spectroscopy. The differential scanning calorimetry(DSC) and the thermal gravimetric analysis(TGA) were used to characterize the thermal property of polymers. The results indicate that though the glass transition temperature(Tg) of polymers increases with increasing the ratio of NLO groups, the polymers with different ratios of NLO groups still all show low glass transition temperatures around 60 °C, and good thermal stability, which are favorable to the practical application of these polymers. The gel permeation chromatographic(GPC) result indicates that these polymers all have high-molecular-weight which is favorable to the long term stability of the material. Further, these polymers have good solubility in chloroform solvent, and the solutions can easily be fabricated into optically transparent films. Gain coefficients of 75 cm-1, 185 cm-1 and 66 cm-1 can be observed at zero external electric field without any addition agent or pre-poling for polymers P-2, P-3 and P-4 respectively. The different contents of NLO groups result in the different properties of polymers P-2, P-3 and P-4.     

Syntheses, Crystal Structures, and Properties of Two Mixed-ligand Coordination Polymers： [Zn（bdc）（1,3-bimb）]_n and {[Mn_2（ox）_2（1,3,5-tib）_（4/3）]·4H_2O}_n

Two new coordination polymers,[Zn（bdc）（1,3-bimb）]n（1） and {[Mn2（ox）2（1,3,5tib）4/3]·4H2O}n（2）（H2ox = oxalic acid,H2bdc = terephthalic acid,1,3-bimb = 1,3-bis（imidazol-1ylmethyl）benzene,1,3,5-tib = 1,3,5-tri（imidazol-1-yl）benzene）,were synthesized and characterized by elemental analysis,IR,powder X-ray diffraction（PXRD）,and thermogravimetric（TG） analyses.X-ray diffracation analysis reveals that two kinds of zigzag chains [Zn（bdc）]n and [Zn（1,3-bimb）]n in compound 1 are interweaved to form a 3D 4-fold interpenetrated 66-dia framework.In compound 2,Mn（1） and Mn（2） are linked via 1,3,5-tib ligands to form two different nets of [Mn6（1,3,5-tib）6 ]n along the ab plane with inner-or outer-shape N–Mn–N angles,which are connected by 1D infinite [Mn2（ox）2 ]n chains via Mn–O bonds to result in a（3,3,3,4,4）-connected（4·8·10）3（4·82）3（4·83·102）6（82·104·3）3（83）4 topology.Moreover,the photoluminescence of 1 has been investigated.The crystal of 1 crystallizes in orthorhombic,space group Pna2 with a = 13.2267（6）,b = 9.1717（4）,c = 17.4492（8）,V = 2116.79（16）3,Z = 4,C22 H18N4O4 Zn,Mr = 467.77,Dc = 1.468 g/cm3,F（000） = 960 and μ（MoKα） = 1.197 mm-1.The final R = 0.0280 and wR = 0.0618 for 3695 observed reflections with I 2（I） and R = 0.0389 and wR = 0.0653 for all data.The crystal of 2 crystallizes in rhombohedral,space group R-3 with a = 22.080（8）,c = 31.19（2）,V = 13167（11） 3,Z = 18,C24 H25 Mn2 N8 O13,Mr = 743.40,Dc = 1.688 g/cm3,F（000） = 6822 and μ（MoKα） = 0.945 mm-1.The final R = 0.0429 and wR = 0.1035 for 5160 observed reflections with I 2（I） and R = 0.0824 and wR = 0.1244 for all data.     

Theoretical Calculations of the pKa Values of 1-Aryl-4-0rooylpiperazine Drugs in Aqueous Solution

Theoretical calculations were carried out to predict the aqueous-phase acidities of a series of drug 1-phenyl-4-propylpiperazine and its derivatives. The performances of the density functional theory（DFT） methods B3LYP and B3P86, solvation models[the polarized continuum model（PCM） and the conductor-like polarized conti- nuum model（CPCM）], and the basis set effect were tested. A comparison between the theoretical and experimental pKa values for para-substituted 1-phenyl-4-propylpiperazines reveals that the accuracy of B3LYP is better than that of B3P86, and the basis set 6-31＋＋G（d,p） and the CPCM model are suitable for calculating pKa values of the substituted 1-phenyl-4-propylpiperazine. For the investigated compounds, a reasonable agreement between the experimental and calculated oKo values was also observed.     

Syntheses and Crystal Structures of Three Cadmium（II） Coordination Complexes Based on Flexible 1,2-Bis（imidazol-1~ˊ-yl）ethane

Three Cd（II） coordination complexes,{[Cd（bime）3]（NO3）2·（H2O）3}n（1）,[Cd（bime）Br2]n（2） and [（H2bime）（CdBr4）（H2O）]n（3）（bime = 1,2-bis（imidazol-1-yl）ethane）,have been prepared and characterized.Single-crystal X-ray diffraction analysis reveals that 1~3 crystallize in the trigonal space group P-3,monoclinic space group C2/c and triclinic space group P1,respectively.In 1,bime bridges six-coordinated Cd（II） to generate a two-fold interpenetrating 3D coordination polymer,in which NO3- is not involved in coordination,but serves as a void filler to balance the charge of the 3D framework.The six NO3- and six uncoordinated water molecules form an unprecedented 24-membered macrocycle through hydrogen bonding interaction.In 2,bime in an anti-conformation links the CdBr2 units into a zigzag chain.In 3,bime does not take part in coordination,but is protonated to act as a counter cation of [CdBr4 ]2-.The hydrogen bonds between H2bime and [CdBr4]2- result in the formation of a supramolecular chain.     

A Quantum Chemical Investigation on the Antioxidant Activity of Licoisoflavone Derivatives

In this paper,21 substituents with various electron donating and electron withdrawing characters were placed in the available positions of Licoisoflavone in order to study their effect on the three O–H bond dissociation enthalpies and ionisation potential via DFT/B3LYP method.Results show that the B-ring is more important than the A-ring from the BDE and IP point of view because the radical structure formed after hydrogen atom abstraction from the 4-OH group can be stabilized by the resonance between the three rings.The results show that intramolecular hydrogen bonding effects are able to considerably stabilize the parents and radicals.The NBO analysis results also confirmed the intramolecular hydrogen bond stabilization.The formation of strong intramolecular hydrogen bonds and suitable spin density distributions in several radicals result in low BDE and IP values.The calculated BDE and IP values have been correlated with Hammett constants.The found dependencies are suitably linear,which can be important for the synthesis of novel antioxidants based on Licoisoflavone.     

Construction of a 2D Cd（II） Coordination Polymer Based on a V-shaped Bidentate Ligand

A two-dimensional（2D）coordination polymer{[Cd（bdc）（dpb）]·H2O}n（1）has been prepared by solvothermal reaction of 1,3-dipyridyl benzene（1,3-dpb）with deprotonated1,4-benzenedicarboxylate（H2bdc）,and was characterized by elemental analysis,IR spectroscopy,and X-ray single-crystal diffraction.It crystallizes in the monoclinic system,space group C2/c with a=15.1839（12）,b=20.7585（17）,c=7.2989（6）,β=117.3450（10）°,V=2043.5（3）3,C24H18N2O5Cd,Mr=526.81,Dc=1.712 g/cm3,F（000）=1056.0,μ=1.110 mm-1and Z=4.The neighboring Cd（II）ions link the bdc2-anions and 1,3-dpb to form an infinite 2D sheet,and such two2D sheets are interlocked with each other to form a 2D→2D sheet.Two groups of interlocked sheets are further linked together by intermolecularπ···πinteraction,giving a 3D supramolecular network.In addition,the fluorescence property of 1 was also studied.     

Syntheses, Structures and Characterization of Two New Pb~II Polymers Built on a Kinked Flexible Thiodiacetic Acid Ligand

Two new PbII metal-organic coordination polymers,namely,[Pb(tda)]n(1) and [Pb(tda)(phen)]n(2)(H2 tda = thiodiglycolic acid,phen = 1,10-phenanthroline),were synthesized under hydrothermal conditions and characterized by elemental analysis,IR,UV spectra,TG technique and X-ray crystallography.Complex 1 crystallizes in the orthorhombic system,space group Iba2 with a = 9.0417(14),b = 19.360(4),c = 7.5741(12),C4H4O4PbS,Mr = 355.32,V = 1325.8(4)3,Dc = 3.560 g·cm-3,F(000) = 1264,μ(MoKa) = 25.711 mm-1,S = 1.086 and Z = 8.The final refinement gave R = 0.0387 and wR = 0.0986 for 3077 observed reflections with I > 2σ(I).Complex 1 is a 2D infinite grid-like(4,4) topological structure constructed by PbII atoms and tda anions,in which tda ligands exhibit bis(syn,syn-bridging bidentate,chelating-bridging tetradentate) mode.Complex 2 crystallizes in the triclinic system,space group P1 with a = 8.3570(17),b = 8.7591(18),c = 10.895(2),α = 76.00(3),β = 80.50(3),γ = 77.61(3)°,C16H12N O4PbS,Mr = 535.53,V = 750.4(3)3,Dc = 2.370 g·cm-3,F(000) = 504,μ(MoKa) = 11.405 mm-1,S = 1.018 and Z = 2.The final refinement gave R = 0.0332 and wR = 0.0629 for 3360 observed reflections with I > 2σ(I).Complex 2 is a 1D chain structure,in which phen ligands are attached on both sides of the 1D chain and tda ligand exhibits a bis(syn,syn-bridging bidentate,chelating tridentate) mode.Finally,complex 2 is extended into a 2D supramolecular structure by strong π···π stacking interactions.     

A dual ligand targeted nanoprobe with high MRI sensitivity for diagnosis of breast cancer

Antibody targeted delivery is an effective strategy to improve the diagnostic imaging outcome of nanoscale imaging agents in the focal areas.Dual targeting micelles encapsulating superparamagnetic iron oxide were prepared from the amphiphilic block copolymer poly(ethylene glycol)-poly(ε-caprolactone)(PEG-b-PCL) with different targeting ligands cRGD and scFv-ErbB single chain antibody conjugated to the distal ends of PEG block.The breast cancer animal model was established by subcutaneous injecting the BT474 cells into the BALB/c-nu female nude mice and then employed to assess the potential of the dual ligand targeted magnetic micelles as a novel MRI contrast agent on a 1.5 T clinical MRI scanner.The T2 signal intensity of the tumor in animals receiving the dual ligand targeted magnetic micelles via tail vein decreased more significantly than the single ligand targeted and nontargeted magnetic micelles.These results indicate that the dual ligand targeted magnetic micelles,cRGD/scFv-ErbB-PEG-PCL-SPION,have great potential to act as a new type of effective nanoscale MRI contrast agent for early diagnosis of breast cancer.     

Production of hydrogen-rich gas and multi-walled carbon nanotubes from ethanol decomposition over molybdenum modified Ni/MgO catalysts

A series of molybdenum modified Ni/MgO catalysts(Ni-Mo/MgO) with different loading ratios of Ni : Mo were prepared by impregnation method. Ethanol decomposition to co-produce multi-walled carbon nanotubes and hydrogen-rich gas at temperatures of 600–800 ℃ was investigated over the synthesized Ni-Mo/MgO catalysts. The results showed that the catalytic activity depended strongly on the reaction temperature and loading ratio of Ni : Mo. According to the gaseous and solid products obtained, the reaction pathways for ethanol decomposition were suggested.     

Electronic Structures and Optical Properties of HgGa_2X_4 （X=S,Se,Te）Semiconductors

The first-principles density functional calculations are performed to study the geometries and electronic structures of HgGa2X4（X = S,Se,Te） semiconductors with defect chalcopyrite structures,and the optical properties of all crystals are investigated systematically.The results indicate that these compounds have similar band structures and the band gap decreases from S to Se to Te.For the linear optical properties,three crystals show good light transmission in the IR and part visible regions,and in particular,HgGa2S4 and HgGa2Se4 crystals possess moderate birefringence.For the nonlinear optical properties,these crystals have stronger second harmonic generation（SHG）,and are theoretically predicted to have larger second-order static SHG coefficients（ 30 pm/V）.The SHG of HgGa2X4（X = S,Se,Te） semiconductors can be attributed to the transitions from the bands near the top of valence band derived from X（X = S,Se,Te） p states to the unoccupied bands contributed by the p states of Ga atoms.Our results indicate that the HgGa2S4 and HgGa2Se4 compounds are good candidates for nonlinear optical crystals in the IR region.     

Synthesis,Structures and Properties of Two Complexes Based on Benzimidazole or Benzothiazole Ligand

Two complexes,Co（Hbim）2（NCS）2（Hbim=benzimidazole）（1） and [Cu（Hbzt）SCN]n（Hbzt=benzothiazole） （2） were synthesized by the same synthesis method and characterized by elemental analysis,infrared spectroscopy（IR）,thermogravimetric analysis（TGA）,X-ray powder diffraction（XRPD） and single-crystal X-ray diffraction.The results from the single-crystal X-ray diffraction indicate that complex 1 is zero-dimensional（0D） framework and complex 2 is 2-dimensional（2D） framework.In complex 2,the 3-dimensional（3D） supermolecular architecture was built up by means of π-π stacking interaction,and two helical chains existed in its structure.The luminescence properties and the magnetic properties of the two complexes were investigated.     

Light-harvesting Complex Ⅱ Sensitized Oxide Photoanodes with Organic Acceptor Molecule as Electron Transfer Mediator

Dye sensitized solar cell（DSSC） is a promising thin film solar cell that has been widely investigated after its birth because of its advantages,such as flexibility,low-cost,easyfabrication and so on[1-3].For DSSCs,sensitizers play a core role due to their responsibility for the generation of the photo carriers resulted from light absorption and the transfer of the photo-generated electrons into semiconductor photoanodes[4].Keywords：Light-harvesting complex Ⅱ; Anthraquinone 2-carboxylic acid; ZnO; TiO2 nanostructure; Solar cell     

Synthesis and Crystal Structure of 5,17-Diformyl-11,23-di（tert-butyl）25,26,27,28-tetrapropoxy-calix[4]arene

The title compound 5,17-diformyl-11,23-di（tert-butyl）-25,26,27,28-tetrapropoxycalix[4]arene has been synthesized by selective formylation of 5,11,17,23-tetra（tert-butyl）25,26,27,28-tetrahydroxycalix[4]arene in three steps and characterized by1H NMR and X-ray single-crystal diffraction.The crystal belongs to the monoclinic system,space group C2/c with a = 25.760（3）,b = 10.9952（10）,c = 18.630（2）,β = 119.985（4）°,V = 4570.4（9）3,Z = 4,Dc = 1.106 g/cm3,Mr = 761.01,F（000） = 1648,μ = 0.071 mm-1,MoKa radiation（λ = 0.71073）,R = 0.0710 and wR = 0.2411 for 3234 observed reflections with I 2σ（I）.X-ray analysis reveals that the title compound adopts a pinched cone conformation which leads to an open cavity.Intermolecular C–H O weak interactions link the molecules along the bc plane,which are effective in the stabilization of the crystal structure.     

Enzymatic Promiscuity： ＂Amano＂ Lipase AS-catalysed Synthesis of Naphthopyran Derivatives in Anhydrous Media

＂Amano＂ lipase AS（lipase from Aspergillus niger）, which naturally hydrolyzes triglycerides, was found promiscuously to catalyze multi-component reactions of aromatic aldehydes with malononitrile and β-naphthol to prepare naphthopyran derivatives in anhydrous organic solvents in moderate to good yields.     

Metal-organic Chemical Vapor Deposition of GaSb/GaAs Quantum Dots： the Dependence of the Morphology on Growth Temperature and Vapour V/Ⅲ Ratio

GaSb quantum dots have been widely applied in optoelectronic devices due to its unique electrical and optical properties.The effects of metal-organic chemical vapor deposition（MOCVD） parameters,such as growth temperature and vapour V/Ⅲ ratio[V/Ⅲ ratio means the molar ratio of trimethylgallium（TMGa） and triethylantimony（TESb）],were systematically investigated to achieve GaSb quantum dots with high quality and high density.The features of surface morphology of uncapped GaSb quantum dots were characterized by atomic force microscope（AFM） images.The results show that the surface morphologies of quantum dots are strongly dependent on growth temperature and vapour V/Ⅲ ratio.GaSb quantum dots with an average height of 4.94 nm and a density of 2.45× 1010 cm-2 were obtained by optimizing growth temperature and V/Ⅲ ratio.     

Synthesis of a new ordered mesoporous NiMoO4com-plex oxide and its efficient catalytic performance foroxidative dehydrogenation of propane

Highly ordered mesoporous NiMoO4material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4with the coexistence of α-NiMoO4and β-NiMoO4showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoO4was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogenation of propane in comparison with bulk NiMoO4.     

Crystal Structure, Hirshfeld Surface Analysis and Quantum Mechanical Study of a Cocrystal Based on 1,3-Di（4-pyridyl）propane and 3-（（4~′-Carboxybenzyl）oxy） Benzoic Acid

A cocrystal based on 1,3-di(4-pyridyl)propane and 3-((4′-carboxybenzyl)oxy)benzoic acid,C13H14N2·C15H12O5,has been synthesized and characterized by single-crystal X-ray diffraction.The compound crystallizes in monoclinic,space group P21 /c with a = 11.639(4),b = 9.808(3),c = 20.854(6),β = 91.242(7)°,V = 2380.0(13)3,C28H26N2O5,Mr = 470.51,Dc = 1.313 g/cm3,μ(MoKα) = 0.091 mm-1,F(000) = 992,Z = 4,the final R = 0.0677 and wR = 0.1477 for 4175 observed reflections(I > 2σ(I)).Intermolecular N H···O hydrogen bonds link two kinds of components into a one-dimensional chain in [10-1] direction and adjacent chains are further arranged into a two-dimensional network by π···π and C H···π interactions.Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that the close contacts are mainly focused on weak interactions.The theoretical investigations with HF/6-31G(d) method were performed,and its stability,frontier molecular orbital composition and Mulliken charge distribution were also discussed.     

Investigation of the Spin Crossover Complex [Fe（bapbpy）（NCS）_2 ] in Its Low-spin and Highspin State by DFT/TD-DFT/BS-DFT Calculations

The spin crossover（SCO） compound [Fe（bapbpy）（NCS）2],where bapbpy contains two fused N,N-bis（2-pyridyl）amines,has been studied by DFT/TD-DFT/BS-DFT methods.Several density functionals and basis sets were used in the calculation to obtain optimized geometries of the compound in the low-（LS） and high-spin（HS） states.The vibrational modes and IR spectra,spin splitting energies,excited states and UV/Vis absorption spectra were obtained.The structural parameters of the calculated isolated complex are in good agreement with the X-ray data.We investigate three dimers of [Fe（bapbpy）（NCS）2] complex for their magnetic properties.It has been found that the complex（1,3） has ferromagnetic character while the others are antiferromagnetic in nature by using a broken symmetry approach in the DFT framework（BS-DFT） with support from the coupling constant values（J） and spin density plots.