Impact of Cr(Ⅲ)complexation with organic acid on its adsorption in silts and fine sands

Trivalent chromium(Cr(Ⅲ))can form stable soluble complexes with organic components,altering its adsorption properties in the water-soil environment.This increases the risk of Cr(Ⅲ)migrating to deeper soils and transforming into toxic Cr(VI)due to the presence of manganese oxides in sediments.In this study,Citric Acid(CA)was selected as a representative organic ligand to prepare and characterize Cr(III)-CA complexes.The characteristics,mechanisms and environmental factors influencing the adsorption of Cr(Ⅲ)-CA on porous media(silts and fine sands)were investigated in the study.The results show that Cr(Ⅲ)coordinates with CA at a 1:1 molar ratio,forming stable and soluble Cr(Ⅲ)-CA complexes.Compared to Cr(III)ions,the equilibrium adsorption capacity of Cr(Ⅲ)-CA is an order of magnitude lower in silts and fine sands.The adsorption of Cr(Ⅲ)-CA in silts and fine sands is dominated by chemical adsorption of monolayers,following the pseudo-second-order kinetic equation and the Langmuir isotherm adsorption model.Varying contents of clay minerals and iron-aluminum oxides prove to be the main causes of differences in adsorption capacity of Cr(Ⅲ)-CA in silts and fine sands.Changes in solution pH affect the adsorption rate and capacity of Cr(Ⅲ)-CA by altering its ionic form.The adsorption process is irreversible and only minimally influenced by ionic strength,suggesting that inner-sphere complexation serves as the dominant Cr(Ⅲ)-CA adsorption mechanism.

Effects of Oleanolic Acid on the Immune Complex Allergic Reaction and Inflammation

When oleanolic acid (OA) was administered ig before and after sensitization on d 1 to d 5 and d 11 to d 17,it had no apparent effect on Arthus reaction.When it was administered at 48,24 and 1 h before challenge,however,Arthus reaction was significantly inhibited.OA showed markedly suppressive effects on reversible passive Arthus reaction and leukocyte migratory response.It could significantly stabilize erythrocyte membrane,inhibit the swelling of the rat's hind paw induced by in- jecting mycostatin,reduce the acid phosphatase content in the inflammatory exudate,suppress the syn- thesis or release of PGE,histamine,LTB4 and kinin,and the phlogistic action of PGE_2,histamine,5- HT and kinin.In addition,it could decrease the content of malonyldialdehyde (MDA) in hepatic tissue of alcohol-intoxicated mice,and increase the activity of catalase (CAT) in hepatic tissue of mice.OA had no apparent effect on the activity of super-oxide dismutase (SOD) in rat serum,on the content of immune complex in serum of rat with Arthus reaction,on the phagocytosis of monocytc-macrophage system,on the clearance of enzyme-containing immune complex by macrophage,or on the activity of total complement.

Cu(Ⅱ),Ni(Ⅱ)Complexation with Acid Alizarine Blue B in the Presence of Cetyltrimethylammonium Bromide

The coordination reactions of Cu（Ⅱ） and Ni（Ⅱ） with acid alizarine blue B （AABB） in the presence of cetyltrimethylammonium bromide （CTAB） micelle were investigated using the microsurface adsorptionspectral correction technique （MSASC）. The aggregation of AABB on CTAB followed the Langmuir isothermal adsorption law. The enrichment of AABB on CTAB sensitized the complexation between Cu（Ⅱ） or Ni（Ⅱ）and AABB. The binding ratio of AABB to CTAB was 1：2.5, and monomeric aggregate, AABB2CTAB5, was formed with an adsorption constant of 5.95×10^5 at 20 ℃ or 2.48×10^5 at 40 ℃. In the ternary complexation, the ratio of AABB：Cu and AABB：Ni were 1：1 and 1：2.5, respectively. Two types of aggregates, Cu2.AABB2·CTAB80 and Ni5.AABB2.CTAB80, were formed.

Synthesis,Characterization and Antibacterial Properties of Rare Earth (Ce^(3+) ,Pr^(3+) ,Nd^(3+) ,Sm^(3+) ,Er^(3+) ) Complexes with L-Aspartic Acid and o-Phenanthroline

Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar conductance, FT-IR, Raman, UV-VIS and TG-DTA. The compositions of the complexes were confirmed to be: RE( Asp)3PhenCl3·3H2O (RE: Ce3+ , Pr3+ , Nd3+ , Sm3+ , Er3+ ). The antibacterial activity test shows that all these complexes exhibit excellent antibacterial ability against Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial spectrum of the complexes are broad.

ATR-FTIR and XPS study on the structure of complexes formed upon the adsorption of simple organic acids on aluminum hydroxide

Information on the binding of organic ligands to metal （hydr）oxide surfaces is useful for understanding the adsorption behaviour of natural organic matter on metal （hydr）oxide. In this study, benzoate and salicylate were employed as the model organic ligands and aluminum hydroxide as the metal hydroxide. The attenuated total reflectance Fourier transform infrared （ATR-FTIR） spectra revealed that the ligands benzoate and salicylate do coordinate directly with the surface of hydrous aluminum hydroxide, thereby forming innersphere surface complexes. It is concluded that when the initial pH is acidic or neutral, monodentate and bridging complexes are to be formed between benzoate and aluminum hydroxide while bridging complexes predominate when the initial pH is alkalic. Monodentate and bridging complexes can be formed at pH 5 while precipitate and bridging complexes are formed at pH 7 when salicylate anions are adsorbed on aluminum hydroxide. The X-ray photoelectron （XP） spectra demonstrated the variation of C 1 s binding energy in the salicyate and phenolic groups before and after adsorption. It implied that the benzoate ligands are adsorbed through the complexation between carboxylate moieties and the aluminum hydroxide surface, while both carboxylate group and phenolic group are involved in the complexation reaction when salicylate is adsorbed onto aluminum hydroxide. The information offered by the XPS confirmed the findings obtained with ATR-FTIR.

A Series of Mononuclear Complexes Constructed from Transition Metals and Amino Acid Derived Ligands: Syntheses, Structures and Photoluminescence

Eight neutral mononuclear complexes constructed from transition metals （M = Co（Ⅱ）, Ni（Ⅱ）, Cu（Ⅱ）, Zn（Ⅱ）, Cd（Ⅱ）） and ligands N-（2-pyridylmethyl）-L-phenylalanine （L-Hpmpa） and N-（2-pyridylmethyl）-L-tyrosine （L-Hpmtyr） have been synthesized by both hydrothermal and conventional room temperature reactions. Four of them have been structurally characterized by single-crystal X-ray diffractions. They are： [Co（L-pmpa）2·2H2O] 1, [Ni（L-pmpa）2·2H2O] 2, [Cu（L-pmpa）2·2H2O] 3 and [Cu（L-pmtyr）2·2H2O] 4. Single-crystal X-ray analysis, IR and elemental analysis revealed that complexes 1, 2 and 3 are isostructural. Powder X-ray diffraction, IR and elemental analysis revealed that complexes 4, 5 （Zn[L-pmtyr]2·2H2O）, 6 （Cd[L-pmtyr]2·2H2O）, 7 （Co[L-pmtyr]2·2H2O） and 8 （Ni[L-pmtyr]2·2H2O） are isostructural. The photoluminescence properties of L-Hpmtyr ligand, compounds 5 and 6 were also investigated.

Synthesis,Characterization and Fluorescence Properties of Europium,Terbium Complexes with Biphenyl-4-Carboxylic Acid and o-Phenanthroline

Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen) L3·1/2H2O; Tb (phen) L3·H2O and Tb0.5 RE0.5(Phen)L3·1/2H2O. (RE = Y3+, La3+ and Gd3+; L = biphenyl 4-carboxylic acid; phen = o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE (III ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3 + is raised by inert fluorescent rare earth ions (Y3+ , Gd3+ and La3+ ), but in Tb3+ hetero-nuclear rare earth complexes the intensity of Tb3+ ions are quenched by the inert fluorescent rare earth ions.

An investigation of oxygen pressure acid leaching of Gacun complex Cu-Pb bulk concentrate

The treatment of the Gacun complex Cu-Pb bulk concentrate with high Zn,Ag,etc.,by oxygen pressure acid leaching was studied.The pri-mary copper and leadminerals in the concentrate are tetrahedrite and galena.The treatment of tetrahedrite was rarely studied,and most of silver occurred in themineral too.The optimum operating parameters of oxygen pressure acid leaching were established by conditional tests.Under these parameters,the result of pilot scale test showed that the leaching percentages of copper and zinc were separately as high as 98.9 wt.% and 94.9 wt.%,while lead and silver were transformed into sulfate and sulfide precipitations,respectively.The copper and zinc in lixivium were reclaimed by extraction-electrowinning and purification-electrowinning,respectively,and the lead and silver in the residue were reclaimed separately by carbonate transformation-silicofluoric acid leaching and thiourea leaching.

Preparation of Ternary Lanthanide Complexes with Unsaturated Acid and 1,10-Phenanthroline, and Their Anti-Inflammatory Action

Four ternary lanthanide complexes with unsaturated acid and 1,10-phenanthroline are prepared in methanol and characterized by elemental analysis, molar conductance, UV, IR, (()~1H) NMR and XPS. The results from this paper show that the complexes Ln(phen)(SA)_3·2H_2O or Ln(phen)(CA)_3·H_2O (Ln=Ce(Ⅲ), Sm(Ⅲ) and Eu(Ⅲ), (phen=1,10-)phenanthroline, SA=Sorbate and CA=Cinnamate) has better anti-inflammatory effect than cerium nitrate and their gremores are steadier than cerium nitrate gremor. And there is a kind of medicament which can replace the cerium nitrate gremor completely in treating burn.

Complex behaviour of trivalent rare earth elements by humic acids

The complexation behaviours of trivalent rare earth elements (La, Ce, Ho and Yb) by two types of humic acids were investigated under a specified set of conditions. Humic acids show quite different complexation capacities an conditional formation constants with the REEs. Apparently there are two types of binding sites in the functional groups of humic acid, in which the first binding sites have stronger ability than the second. Cerium shows the largest complexation capacities and highest formation constants among the four REEs with two humic acids, this anomaly may be relative to the distribution pattern of the REEs in seawater. The experimental results were comparable to the values of other metals reported and provided the basic data for environmental geochemistry of rare earth elements.

Crystal Structure and Luminescence Property of Lanthanide Complexes with 2-Fluorobenzoic Acid and 2,2′-Bipyridine

The two compounds of [Ln（2-FBA）3·2,2＇-bpy ]2（2-FBA = 2-fluorobenzoato, 2,2＇-bpy = 2,2＇-bipyridine, Ln = Eu（1 ）, Dy（2）） were synthesized and their structures were determined by X-ray diffraction method. Crystallized complexes 1 and 2 are isomorphous, monoelinie system with P21/n space group. The two complexes are binuclear molecule with an inversion center. The two lanthanide ions are linked by four bridged 2-FBA ligands and each lanthanide ion is further bonded to one chelated bidentate 2-FBA ligand and one 2,2＇-bipyridine molecule. The coordination number of metal ion is eight. The europium complex exhibits strong red fluorescence. ^5D0→^7Fj（j = 1 - 4） transition emission of Eu^3＋ ion was observed.

Investigation on the syntheses and structures of Y^(Ⅲ) complexes with ami-nopolycarboxylic acids (Ⅳ)

This paper deals with the structure of the Y^iii complex withaminopolycarboxylic acids, synthesis and struc- tural determinationof the complex (NH_4)[Y^III(edta)(H_2O)_3] ·3 H_2O (edta =ethylenediaminetetraacetic acid). The crystal and molecularstructures of the (NH_4)[Y^III(edta)(H_2O)_3] ·3 H_2O complex havebeen determined by single-crystal X-ray structure analysis. Thecrystal of the complex (NH_4)[Y^III(edta)(H_2O)_3] ·3 H_2O belongsto orthorhombic crystal system and fdd2 space group.

Solvothermal Syntheses, Crystal Structures, Thermal Stability and Quantum Chemistry of Dinuclear Trialkyltin Complexes Constructed by Camphoric Acid

Two dinuclear organotin complexes C8H14（CO2SnCy3）2（1）（Cy = cyclohexyl group） and C8H14[CO2Sn（CH2CMe2Ph）3]2（2） were synthesized by the reactions of camphoric acid with tricyclohexyltin hydroxide and bis[tri（2-methyl-2-phenyl）propyltin] oxide under solvothermal conditions, and these complexes were characterized by infrared spectra, elemental analyses, and H NMR spectra. The crystal of 1 belongs to the monoclinic system, space group P21/c with a = 1.83478（19）, b = 1.52707（18）, c = 1.9849（2） nm, β = 122.515（7）°, Z = 4, V = 4.6896（9） nm^3, Dc = 1.324 g/cm^3, μ（MoKα） = 1.103 mm^-1, F（000） = 1952, R = 0.0697 and wR = 0.2040. In addition, thermal stability and quantum chemical calculation of 1 were also studied.

Fluorescence of complexes of EuⅢwith aromatic carboxylic acid-1,10-phenanthroline

The 1,10 phenan throline aromatic carboxylic acid(benzoic acid and o phthalic acid) binary and ternary complexes of europium were synthesized.The fluorescence and FT IR spectroscopy,elemental analysis,UV spectroscopic studies on these complexes were also performed.These complexes can emit strong red fluorescence of Eu? excited by UV light.At the same excited wavelength,the fluorescence spectra of the complexes were also studied.The results indicated that the fluorescence intensities of ternary complexes are stronger than that of binary complexes.The reason is that phenanthroline has higher electron density and higher orbit scope in the conjugated system and consequently an easier energy transfer to the europium ion,which makes the fluorescence intensity of ternary complexes be stronger than that of binary complexes.

Syntheses and Crystal Structures of Three Ag(Ⅰ) Complexes with Chloro-phenylacetic Acid and Nitrogen Heterocyclic Ligand

Three new coordination polymers {[Ag2（2,4-DCPA）（4,4＂-bipy）2（NO3）].（H20）}, （1）, [Ag（2,4-DCPA）（bpp）], （2） and {[Ag（4-DCPA）（bpp）]＇（H20）}, （3）, were synthesized by evaporation methods using 2,4-dichlorophenylacetic acid （2,4-DCPA）, 4-chlorophenylacetic acid （4-DCPA）, 4,4＂-dipyridyl （4,4＂-bipy）, 1,3-bis（4-pyridyl）propane（bpp） and AgNO3. Compound 1 crystallizes in monoclinic, space group P21/c with a = 10.035（2）, b = 17.796（3）, c = 16.448（2） A, fl = 104.086（2）°, V= 2705.9（2） A3, Dc = 1.893 g/cm-3, C28H23C12NsO6Ag2, Mr = 812.15, F（000） = 1608,μ（MoKot） = 1.615 mm-1, Z = 4, R = 0.0310, wR = 0.0832 for 4357 observed reflections （I 〉 20（/））, and R = 0.0362, wR = 0.0873 for all data. Compound 2 crystallizes in monoclinic, space group P21/c with a = 9.840（2）, b = 24.971（5）, c = 9.3301（2）°, fl = 117.504（2）°, V= 2033.5（7） A3, Dc = 1.666 g/cm3, C2tH19C12N202Ag, Mr = 510.15, F（000） = 1024,/I（MoKa） = 1.273 mml, Z= 4, R = 0.0315 and wR = 0.0680 for 2853 observed reflections （1 〉 20（/）） and R = 0.0454, wR = 0.0736 for all data. Compound 3 crystallizes in monoclinic, space group P21/n with a = 15.472（4）, b = 9.000（2）, c = 16.262（4） A, fl = 112.049（4）°, V = 2099.0（8） A3, Dc = 1.562 g/cm-3, C2H22C1N203Ag, Mr = 493.73, F（000） = 1000, μ（MoKa） = 1.111 mm-1, Z = 4, R = 0.0296, wR = 0.0821 for 3059 observed reflections （I 〉 2δ-（I））, and R = 0.0398, wR = 0.0986 for all data. The complexes were characterized by elemental analysis, FT-IR, thermogravimetrie analysis （TGA） and X-ray single-crystal structure analysis. Fluorescence properties of complex 3 and PXRD of 1 and 2 have been studied. As a result, in complex 1, the Ag（I） ion is surrounded by two nitrogen atoms from two bipy ligands to form an infinite chain, and adjacent Ag-bipy chains produce ＂＇rungs＂ of a ladder by silver ions contact. And in complexes 2 and 3, the two-dimensional ,β-sheet like layers are obtained by Ag……Ag interactions.

Hydrothermal Synthesis and Crystal Structure of a New One-dimensional Nickel(Ⅱ) Complex with 2-Pyridinecarboxyic Acid and 4,4′-Bipyridine Ligands

A new metal-organic coordination polymer [Ni[（2-pya）2（4,4′-bipy）]n·6nH2O （2-pya = 2-pyridinecarboxylic acid, 4,4′-bipy = 4,4′-pyridine） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG and single-crystal X-ray diffraction. The complex crystallizes in tetragonal, space group I4 1/α with a = b = 22.5642（19）, c = 10.7118（18） A, V = 5453.8（11） A^3, C22H28N4NiO10, Mr= 567.19, Dc = 1.382 g/cm^3, μ（MoKα） = 0.769 mm^-1, F（000） =2368, Z = 8, the final R = 0.0572 and wR = 0.1254 for 1401 observed reflections （I 〉 2σ（I））. It exhibits a one-dimensional chain-like structure by mixed ligands of 2-pyridinedicarboxylic acid and 4,4′-pyridine.

Study on the Structure of Supramolecular Inclusion Complex of β-Cyclodextrin with Retinoic Acid

Inclusion compound of retinoic acid with (-cyclodextrin was prepared by coprecipitating method, the structure of resulting product was studied by elemental analysis, differential scanning caloriemetry(DSC) analysis, FT-IR spectroscopy and X-ray diffractometry, and the formed supramolecule self-assembles in aqueous solution according to molar ratio 2:1 of host-guest.

Synthesis and Crystal Structure of a New Copper(II) Complex with 4-Cyanobenzoic Acid

A new Cu（Ⅱ） complex [Cu（4-cba）（1,10-phen）（H2O）2]（NO3） （4-Hcba = 4-cyanobenzoic acid） has been synthesized by solvothermal reaction in an ethanol/water mixed solution at 100 ℃ and structurally characterized by single-crystal X-ray diffraction. Crystallographic data： C20H16CuN4O7, Mr= 487.91, triclinic, space group PI, a = 7.8420（2）, b = 9.1070（2）, c = 15.1140（6） A, a = 76.889（9）, β = 81.332（11）, γ = 74.844（ 11）°, V = 1009.89（5） A^3, Z = 2, Dc = 1.605 g/cm^3, F（000） = 498, μ = 1.134 mm^-1, the final R = 0.0379 and wR = 0.0865 for 2977 observed reflections with 1 〉 2σ（Ⅰ）. The Cu（Ⅱ） atom is coordinated by two terminal water molecules, one chelating 1,10-phen molecule and one monodentate 4-cba ligand to form a slightly distorted square pyramid. The title complex molecules are connected through hydrogen bonds and π-π stacking interactions to generate a 2D layered network. The thermogravimetric analysis of the title complex has also been discussed.

Synthesis, Characterization and Fluorescence of Terbium(Ⅲ) Complexes with Phenylglyoxylic Acid and 2,2-Dipyridine, 1,10-Phenanthroline, Triphenyl Phosphine Oxide

Three new complexes TbL3dipy （H2O）2, TbL3phen （H2O） 2 and TbL2 （TPPO） 2NO3 were synthesized （L = phenylglyoxylate ion, dipy = 2, 2-dipyridine, phen = 1,10-phenanthmline, TPPO = Triphenyl phosphine oxide）. Elemental analysis, conductivity, IR spectra, and ^1HNMR spectra studies were performed. IR spectra indicate that the carboxylate ion of phenylglyoxylate is coordinated to the Tb（Ⅲ） ion as an unidentate ligand. In ^1HNMR, the signals of different hydrogens in phenylglyoxylate ion shift upfield. The excitation and emission spectra of the three solid complexes were recorded at morn temperature, in which the optimum excitation wavelengths are, 361.0, 359.0 and 367.0 nm for these three complexes, respectively. Four emission bands due to the ^5D4-^7Fj（j = 6, 5, 4, 3） transitions were observed for TbL3dipy（H2O）2（489.0, 545.0, 584.0, 620.0 nm） and TbL3phen（H2O）2（490.0, 544.0, 583.0, 620.0 nm）. Under the same conditions, only one emission band due to the ^5D4-^7F5 transition was observed for the complex TbL2（TPPO）2NO3. The emission intensity of TbL3dipy（H2O）2 is the strongest among the three complexes.

Synthesis and spectroscopic characterization of fluorescent solid rare-earth complexes with hydroxamic acids

The complexes RE_2(DHYA)_3 centre dot nH_2O in the title bar were synthesizedthrough some reactions of trivalent rare-earth ions. In the process of synthesis, dihydroxamicacids were taken as ligands while the alcohol was taken as a solvent. The ligands includedadipylhydroxamic acid (ADHA), p-phthalichydroxamic acid (PPHA), oxalohydroxamic acid (OXHA),butadihydroxamic acid (BDHA), o-phthalichydroxamic acid (OPHA), benzoylhydroxamic acid (BHA), etc.Measured at 25 deg C, the molar conductances in various modes are 13.00-21.05 S centre dot cm^2centre dot mol^(-1), which shows that rare-earth complexes are nonelectrolytes and the hydroxaminogroups of the complexes have taken part in bonding. Infrared spectra, ultraviolet spectra, nuclearmagnetic resonance (~1HNMR) spectra, and fluorescence spectra were used to investigate thecomplexes. Experiments have proved that the complexes of En^(3+)and Tb^(3+) with aromatic hydroxamicacids have good fluorescent characteristics.