Synthesis of rare earth sulfides and their UV-vis absorption spectra

Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.

Contacted Ion Pairs in Aqueous CuCl2 by the Combination of Ratio Spectra, Difference Spectra, Second Order Difference Spectra in the UV-Visible Spectra

The microstructure of aqueous CuCl2 has been studied through lots of technologies for many years; however, it remains a controversial subject. In this study, a new spectroscopic method has been proposed to analyze the UV-visible spectra of thin fihn of CuCl2/H2O solutions at different concentrations. This method is the combination of ratio spectra, difference spectra and second order difference spectra. By using this method, two new bands at -230 and -380 nm are obviously observed. The bands are assigned as the contacted ion pairs [CuCl3（H2O）n]- or [CuCl4（H2O）n]2-, which demonstrates that ion pairs exist in the CuCl2/H2O solution. Such finding agrees with the recent theoretical spectra obtained by time-dependent density functional theory. Furthermore, the populations of the contacted ion pairs are discussed. This study not only offers the direct spectroscopic evidence of [CuCl3（H2O）n]- or [CuCl4（H2O）n]2- in aqueous CuCl2, but also suggests that the spec- troscopic analysis method is powerful to extract the weak bands in a strong overlapping spectrum.

Synthesis, Structure and Spectra Properties of a Novel BOIMPY Compound

A bis-2-iminopyrrole compound（1） and its difluoroboron complex（2） were synthesized and characterized. The crystal of 2 is in the monoclinic system, P2_1/n space group with a = 21.5113（15）, b = 6.3036（3）, c = 21.5064（15） A, V = 2826.3（7） A^3, Z = 4, C_（26.5） H_（25） B_2 ClF_4 N_4 O, M_r = 548.57, D_c = 1.390 g/cm, F（000） = 1132 and μ（MoKα） = 1.787 mm^-1. The final R = 0.0647 and wR = 0.1817 for 10346 observed reflections with I 〉 2σ（I）, and R = 0.0889 and wR = 0.1993 for all data. The molecules of complex 2 self-assemble through C–H×××F hydrogen bonds and form tubular structures which are filled by CH_2 Cl_2 molecules stabilized by C–H×××π interaction. The UV-Vis spectra of complex 2 show great bathochromic shift compared to that of compound 1 due to the difluoroboron complexing. Complex 2 shows fluorescence emission both in solid state and in solution, whereas compound 1 only exhibits fluorescence emission in solid state.

SYNTHESIS AND ELECTRONIC SPECTRA OF RUTNENIUM(Ⅱ)-1,1'-BIISOQUINOLINE COMPLEXES

l,l'-biisoquinoline can coordinate with ruthenfum(Ⅱ) to form a new series of mononuclear complexes and the electronic absorption of these complexes were measured and reasonably assigned.

SYNTHESIS OF MeO-SiO_2:Eu^(3+),Bi^(3+)LUMINOPUORS BY THE SOL-GEL METHOD AND A STUDY OF THEIR LUMINESCENCE SPECTRA

The luminophors MeO-SiO_2:Eu^(3+),Bi^(3+)and MeO-SiO_2Bi^(3+)(Me=Mg.Sr)were synthesized at relatively lower temperature by the sol-gel method using the silica sol as a source of silica.The optimum composition and synthesis conditions were obtained by studying the excitation and emission spectra and the effects of energy transfer from the Bi^(3+)ions to the Eu^(3+)ions.

RAMAN SPECTRA OF HYDROGEN ADSPECIES ON AMMONIA SYNTHESIS IRON CATALYST

Raman peaks at 1951 and 2165 cm^(-1) can be confirmed further by H_2/D_2 isotope exchange as H-adspecies on the doubly promoted iron catalyst for ammonia synthesis and are probably ascribed to two terminally adsorbed H-species.

Rapid Biosynthesis of Silver Nanoparticles Using Cymbopogan Citratus (Lemongrass) and its Antimicrobial Activity

The present study deals with the rapid green synthesis of silver nanoparticles using fresh leaves of Cymbopogan Citratus(Lemongrass). Silver nanoparticles were formed within 8～10 minutes by microwave irradiation using aqueous solution of Ag NO3(1 m M) with fresh leaves extract of Cymbopogan Citratus. The synthesized silver nanoparticles were characterized by using UV-visible spectrophotometer analysis, nanoparticle tracking analyzer, transmission electron microscope and energy dispersive X-ray spectra. The antibacterial activity of these nanoparticles was studied against multiple drug resistant hospital isolates of E.coli, S.aureus,P.mirabilis and hospital isolates of S. typhi, K.pnuemoniae. Also, the antifungal activity of these nanoparticles was studied against C.albicans(hospital isolate) and A.niger(NCIM 616). The synergistic effect of silver nanoparticles along with antibiotics was also studied against multiple drug resistant hospital isolates and found to be effective. The extracellular synthesis of Silver nanoparticles using leaves of Cymbopogan Citratus appears to be rapid and eco-friendly.

Reaction Mechanism,Synthesis and Characterization of Urea-glyoxal(UG) Resin

The reaction mechanism of glyoxal （G） with urea （U） under weak acid condition was theoretically investigated at PW91/DNP/COSMO of quantum chemistry using density functional theory （DFT） method. The results show that the addition reaction of G with U under the conditions mainly involves the reactions of U with protonated glyoxal （p-G）, protonated 2,2-dihy- droxyacetaldehyde （p-G 1） and protonated bis-hemdiol （p-G2） to form two important carbocation reactive intermediates of C-p-UG and C-p-UG1, and two important hydroxyl compounds of UG and UG1. These compounds play important roles in the formation of UG resin. According to the result of quantum chemical calculation, UG resin was synthesized successfully under weak acid conditions. The UG resin was characterized by matrix assisted laser desorption ionization time of flight mass spectrometry （MALDI-TOF-MS）, ultraviolet and visible spectroscopy （UV-vis）, Fourier transform infrared spectroscopy （FT1R） and nuclear magnetic resonance spectroscopy （13CNMR and 1HNMR）. These instrumental analytical results agree with each other and further confirm the addition reaction pathway of glyoxal with urea proposed by quantum chemical calculation.

Compiexation-Coprecipitation Synthesis and Characterization of Neodymium and Antimony Doped SnO_2 Conductive Nanoparticles

Nd and Sb doped SnO2 conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn, Sb2O3 and Nd2O3 as the raw materials. Thermal behavior, crystal phase, and structure of the prepared conductive nanoparticles were characterized by TG/DSC/DTG, FTIR, XRD and TEM techniques, respectively. The resistivity of the prepared conductive nanoparticles was 0.12Ω·cm. TG/DSC/DTG curves show that the precursors lose weight completely before 750℃. FTIR spectrum shows that the vibration peaks are wide peaks in 731 ~ 617 cm-1, and the Nd and Sb doped SnO2 conductive nanoparticles have intense absorption in 4000 ~ 2000 cm-1. Nd and Sb doped SnOi have a structure of tetragonal rutile, and complex doping is achieved well by complexation-coprecipitation method and is recognized as replacement doping or caulking doping. TME shows that the particles are weakly agglomerated, and the size of the particles calcined at 1000℃ranges about 10 nm to 30 nm.

Synthesis and Properties of La and Sb Doped SnO_2 Conductive Nanoparticles

La and Sb doped SnO_2 conductive nanoparticles were prepared by the coprecipitation method with SnCl_4·5H_2O, SbCl_3 and La_2O_3 as the raw materials. Thermal behavior, crystal phase, and structure of the prepared conductive nanoparticles were characterized by TG/DSC/DTG, FTIR, XRD and TEM techniques, respectively. The resistivity of the prepared conductive nanoparticles is 2.5 Ω·cm. TG/DSC/DTG curves show that the precursors lose weight completely before 750 ℃. FTIR spectrum show that the vibration peak are wide peak in 718～615 cm -1, and the La and Sb doped SnO_2 conductive nanoparticles have intense absorption in 4000～2000 cm -1. X-ray powder diffraction pattern of the conductive nanoparticles indicates that the Sb-doping in SnO_2 is replacement doping and La 3+ combines with Sn 4+ and O 2- form La_2Sn_2O_7. TME shows that the particles are weakly agglomerated, and the size of the particles calcined at 1000 ℃ ranged about 20～30 nm.

Synthesis of Mono-esters of Phenyl-and Substituted Phenylphosphonic Acids and Their Performance in Rare Earth Extraction

Methodsfor the synthesis of acidic phenyl-and substituted phenylphosphonates bearing a branched long chain ester alkyl group are described.These synthetic routes are incomparably superior to other methods in vari- ous aspects including better reaction yield and higher purity of the product.The behaviour of the mono(2-butyloctyl)esters and mono(2-methyldodecyl)esters of both phenyl-and o-methylphenylphosphonic acids thus obtained in extraction of lanthanum,praseodymium,neodymium and lutecium as representatives of light and heavy rare earths,is investigated and discussed on the basis of their chemical structure.The dependence of the extraction constants and separation factors accords with the Reactivity-Selectivity Principle in solvent ex- traction proposed by us.The composition and structure of the extracted species have been characterized by infra-red and proton nuclear magnetic resonance spectroscopy in addition to elemental analyses.

Synthesis, Crystal Structure and Characterization of the Host-guest Type UOF

A new uranium（Ⅵ）-polycarboxylate framework with honeycomb（6,3） nets {[Zn（phen）_2（H_2O）_2][（UO_2）_2（BDC）_3]·2H_2O}n（1, BDC = benzene-1,4-dicarboxylate） was hydrotherrmally synthesized by the reactions of Zn（NO_3）_2·6H_2O with phenanthroine, UO_2（NO_3）_2·6H_2O and benzene-1,4-dicarboxylate. The complex was structurally characterized by FT-IR spectroscopy, powder XRD and X-ray single-crystal diffraction. Crystal data for 1： monoclinic, space group Cc with M_r = 1522.19, a = 14.9385（10）, b = 20.4922（13）, c = 15.9728（10） ？, β = 100.1240（10）°, V = 4813.5（5） ？~3, Z = 4, D_c = 2.100 g？cm^（–3）, μ = 7.293 mm^（–1）, F（000） = 2872, the final R = 0.0224 and w R= 0.0677 for 6522 observed reflections with I 〉 2σ（I）. Hydrogen bonds and π-π stacking interactions contribute to the structural extension and stabilization. Experimental band gap of about 3.57 e V indicates its broad gap semiconductor nature. UV-Vis spectra and solid-state luminescence were discussed in detail. The compound exhibits photocatalytic activities for the degradation of rhodamine B.

Luminescence properties of nitrogen-rich Ca-SiAlON:Eu2+ phosphors prepared by freeze-drying assisted combustion synthesis

Nitrogen-rich Eu2+-doped Ca-α-SiAlON phosphors(Cam/2-xSi12-m-nAlm+nOnN16-n:xEu) were synthesized by a freeze-drying assisted combustion synthesis(CS) route. Fast-synthesized products with high purity and uniform particle morphology were confirmed by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The analysis of lattice parameters by comparison with empirical equations showed that the as-prepared phosphors had low oxygen content. A series of samples were prepared according to the stoichiometry of Cam/2-0.08Si12-mAlmN16:0.08 Eu for further research. The influences of m value on the luminescence properties were investigated in detail. As m increased, a redshift phenomenon was observed in both the excitation and emission spectra. First-principle electronic structure calculations showed that the 3d energy level of Ca played an important role in the occurrence of the redshift phenomenon.

Synthesis, Crystal Structure, Magnetic Property and DFT Study of a Novel 2D Polymer [Cu(pdc)(bpy)]·H_2O

A new copper complex [Cu（pdc）（bpy）]·H2 O（1, H2 pdc = 3,5-pyridinedicarboxylic acid, bpy = 2,2-bipyridine） has been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, UV-vis spectroscopy and magnetic measure- ments. Complex 1 crystallizes in monoclinic system, space group P21 /c, a = 10.893（2）, b = 7.3641（15）, c = 1.9921（4）, β = 92.16（3）, V = 1596.9（6）3, Dc = 1.676 g/cm3, Mr = 402.84, Z = 4, F（000） = 820, μ = 1.404 mm-1, the final R = 0.0237 and wR = 0.0693. The Cu（II） ion is five-coordinated by two O atoms from two pdc ligands, one N atom from another pdc ligand and two N atoms from the bpy ligand. The pdc anion, which acts as a tridentate ligand, links three Cu ions, forming（3,3）-connected two-dimensional（2D） sheets. We also studied the electronic structure and orbital energies of complex 1 by DFT methods, and the results are consistent with UV-vis spectrum.

Microwave Synthesis of Silver Nanoparticles Using Different Pentose Carbohydrates as Reducing Agents

A fast, green and readily reproducible microwave-based method for the production of high quality silver nanoparticles （AgNPs） in high yield is presented. Starch is used as a stabilizing agent with few pentose different reducing carbohydrates as D-ribose, D-arabinose and L-arabinose. From the UV-vis peak profile spectra of the solutions of the silver nanoparticles, the authors have investigated the size of the NPs together with the average diameter, shape, and aggregation state of the colloidal AgNPs. TEM measurements and EDX analysis have confirmed the morphology of our AgNPs.

Synthesis and Biomedical Application of SiO₂/Au Nanofluid Based on Laser-Induced Surface Plasmon Resonance Thermal Effect

We described the synthesis of Au coated SiO2 nanoshells linked with NH2 biomolecular ligands using a simple wet chemical method with a particular application for laser tissue soldering. Tunable nanoshells were prepared by using different gold colloidal concentrations. The nanoshells are characterized by UV-vis spectroscopy, FTIR, XRD and AFM. The FTIR results confirmed the functionalized surfaces of silica nanoparticles with NH2 terminal groups. A broad absorption was observed between 470 - 600 nm with a maximum range between 530 - 560 nm. Based on the XRD results three main peaks of Au (111), (200) and (220) were identified. In addition, AFM results showed that the diameter of silica core was between 90 - 110 nm with gold shell thickness between 10 - 30 nm. A possible tissue soldering using gold nanoshells and laser-induced thermal effect based on surface plasmon resonance is demonstrated. In our case this corresponds to 90?C (i.e. below vaporization) using the higher gold concentration (2 ml) at 60 W·cm–2.

Synthesis and Characterization of Europium Doped Ceria

Europium doped CeO_2 was synthesized via combustion synthesis method. The powders were found to be in a single phase. The average crystallite size was found to be about 30nm. It was revealed from photoluminescence spectra that there was an excitation band around 368 nm and a narrow excitation peak at 468 nm. The emission spectrum showed four peaks at 589, 608, 629 and 650 nm.

Complexation-Coprecipitation Synthesis and Properties of Lanthanum and Antimony Doped SnO_2 Conductive Nanoparticles

La and Sb doped SnO2 conductive nanoparticles were synthesized by the complexation-coprecipitation method with Sn, Sb2O3 and La2O3 as the raw materials. Thermal behavior, crystal phase, and structure of the synthesized conductive nanoparticles were characterized by TG/DTA/DSC, FTIR, XRD and TEM techniques, respectively. The resistivity of the synthesized conductive nanoparticles was 0.07 Ω·cm; TG/DSC/DTA curves showed that the precursors lost weight completely before 800 ℃; FTIR spectrum showed that the vibration peak were wide peak in 731.4～586.4 cm-1. The La and Sb doped SnO2 conductive nanoparticles had intense absorption in 4000～2500 cm-1; La and Sb doped SnO2 had a structure of tetragonal rutile; complex doping was achieved well by complexation-coprecipitation method and was recognized as replacement doping or caulking doping; TME showed that the particles were weakly agglomerated, and the size of the particles calcined at 800 ℃ ranged approximately from 10 to 20 nm.

Chelation in Metal Intoxication XLVI:Synthesis of Someα-Mercapto-β-Substituted Aryl Acrylic Acids and TheirIn vitro Cadmium Chelating Ability

Objective To synthesize some new a-mercapto-β-substituted aryl acrylic acids, characterize them and investigate their in vitro cadmium chelating ability. Methods Six α-mercapto-β-substituted aryl acrylic acids were prepared by the alkaline hydrolysis of 5- (aryl methylene) rhodanines, obtained from the condensation of substituted aldehydes and rhodanine following the reported procedure. The new compounds were characterized by elemental analysis, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The liver and kidney from cadmium chloride pre-administered rats were homogenized and their nuclear mitochondrial fraction (NMF) and supernatant cytosol fraction (SCF) were separated. A measured volume of each fraction was dialyzed separately using 'dialysis sack' against buffered-KCl medium containing a compound in the final concentration of 1×10-3 mol/L for 3 h at 37℃. The whole content of 'sack' was subjected to cadmium estimation following digestion with cone. Nitric acid was detected using flame atomic absorption spectrometer. Results The in vitro screening showed that α-mercapto-β-(p-methoxyphenyl) acrylic acid (compound 2) andα-mercapto-β-(m-methoxy, p-hydroxyphenyl) acrylic acid (compound 4) were more effective than α-mercapto-β-thienyl acrylic acid (compound 1) and a-mercapto-β-(p-dimethylaminophenyl) acrylic acid (compound 3) in mobilizing cadmium as their dialyzable chelates. The presence of a methoxy group on the phenyl moiety (compounds 2 and 4) increases the metal chelating ability of mercapto acrylic acids. Conclusions Compounds 2 and 4 seem to have accessibility to the cellular system and capability of chelating-out the intracellularly bound cadmium.

Synthesis, Crystal Structure,Characterization and Quantum Chemical Studies on 1N-Acetyl-3-(2,4-dichloro-5-fluoro- phenyl)-5-(p-methyl-phenyl)-2-pyrazoline

1N-Acetyl-3-（2,4-dichloro-5-fluoro-phenyl）-5-（p-methyl-phenyl）-2-pyrazoline has been synthesized and characterized by elemental analysis, IR, UV-Vis and X-ray single-crystal diffraction. Ab intio calculations have been carded out for the compound by using both B3LYP and HF methods at the 6-31G^＊ basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. The electronic absorption spectra calculated by B3LYP/6-31G^＊ method are approximate to the experiments and the Natural Bond Orbital （NBO） analyses suggest that the above electronic transitions are mainly assigned to n→π^＊ and π→π^＊ transitions. CIS-HF/6-31G^＊ method is not suitable to predict the electronic spectra for the title compound. The calculation of the second order optical nonlinearity was carded out, giving the value of molecular hyperpolarizability equal to 2.194^＋ 10^-30 esu. On the basis of vibrational analyses, the thermodynamic properties of the compound at different temperature have been calculated, revealing the correlation between C p, m^0, S m^0, H m^0 and temperature.