Synthesis, Crystal Structure and Fluorescent Property of a New One-dimensional Cadmium(Ⅱ) Coordination Polymer Based on 3,4-Thiophenedicarboxylic Acid and 1,10-Phenanthroline

A new cadmium（Ⅱ） polymer [Cd（tdc）（Phen）]n 1 （H2tdc = thiophene-3,4-dicar-boxylic acid, Phen = 1,10-phenanthroline） was synthesized under hydrothermal conditions. The compound crystallizes in the triclinic system, space group P , with a = 7.3150（10）, b = 10.3598（14）, c = 10.8784（15） , α = 82.2740（10）, β = 72.9730（10）, γ = 80.236（2）°, V = 773.68（18） 3, Z = 2, Mr = 462.74, Dc = 1.986 Mg/m3, μ = 1.58 mm-1, F（000） = 456, the final R = 0.0218 and wR = 0.0465 for 3361 observed reflections with Ⅰ 〉 2σ（Ⅰ）. The compound presents a one-dimensional （1-D） double-stranded structure and exhibits fluorescent emission at room temperature. Furthermore, infrared spectroscopy, elemental analyses, thermogravimetric analysis and powder X-ray diffraction properties of the compound are also investigated.

Synthesis and Structural Characterization of a New Cadmium(Ⅱ) Complex Bridged by Endo-norbornene-cis-5,6-dicarboxylic Acid

A polynuclear complex [Cd（endc）（H20）]n·nH2O （endc = endo-norbornene-cis- 5,6-dicarboxylate anion） has been synthesized by the hydrothermal reaction of cadmium nitrate tetrahydrate with endo-norbornene-cis-5,6-dicarboxylic acid in 1：1 molar ratio, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with α = 1.16471（7）, b = 0.95334（7）, c = 0.91109（9） nm, Z= 4, V= 1.01035（14） nm^3, D, = 2.160 g/cm^3,μ = 2.172 mm^-1, F（000） = 648, R = 0.0302 and wR = 0.0752. According to structural analysis, each Cd（II） ion is coordinated to six O atoms from three endc anions and one water molecule, giving a distorted octahedral geometry. Two- dimensional layer arrangement of the title complex is constructed from the bridging nature of endc. It is worth notice that adjacent two-dimensional layers are joined together to form a three-dimensional supramolecular framework via intermolecular hydrogen bonding interactions.

A Novel Tetraiodocadmate（Ⅱ） - PVC Membrane Electrode for the Potentiometric Determination of Cadmium（Ⅱ）

A novel tetraiodocadmate（Ⅱ）-selective membrane electrode consisting of tetraiodo-cadmate（Ⅱ）-rhodamin B ion pair （TICRhB） dispersed in a PVC matrix plasticized with 2-nitrophenyl octyl ether （o-NPOE） was prepared. The sensor demonstrated a near-Nernstian response for 1×10^-2 to 2×10^-6 mol/L cadmium （Ⅱ） at 25℃ with an anionic slope of 29.0. It revealed very good selectivity for Cd^2＋ with negligible interference from many cations and anions, and could be used in a pH range of 3 to 6.

Synthesis and Crystal Structure of a New Cadmium(Ⅱ) Coordination Polymer with Ethylenediaminetetraacetic Acid

A new cadmium（Ⅱ） coordination polymer,namely,[KCd2（edta）I]n（1,H4edta = ethylenediaminetetraacetic acid）,has been prepared and structurally characterized by single-crystal X-ray diffraction.Crystallographic data for 1：C10H12Cd2IKN2O8,Mr = 679.02,monoclinic,space group P21/n,a = 9.870（5）,b = 8.989（4）,c = 19.082（10） ,β = 104.581（10）o,V = 1638.5（13） 3,Z = 4,Dc = 2.753 g/cm3,μ = 4.776 mm-1,F（000） = 1272,the final R = 0.0473 and wR = 0.1311 for 2846 observed reflections with I 〉 2σ（I）.Polymer 1 features a 2-D layered structure,in which each edta4-ligand chelates/bridges five adjacent six-/seven-coordinated Cd（Ⅱ） centers with all ten donors（eight oxygen and two nitrogen） involved with coordination.Additional iodide I-ions as counterions are bound to the Cd（Ⅱ） centers in a terminal mode and the potassium K＋ ions are located in the layers and surrounded by O and I atoms from neighboring environment.The thermal stability of 1 has been discussed.

Hydrothermal Synthesis,Crystal structure,DFT and Application of a Dinuclear Cadmium(Ⅱ) Complex Based on NPHSNPAB

A new dinuclear cadmium（Ⅱ） complex,[Cd（NPHSNPAB）（H_2O）_2（CH_3CH_2OH）]_2（1）,was synthesized by the hydrothermal reaction of N-phenyl-2-[2-hydroxyl-3-sulfo-5-nitrophenylazo]butadiene-1,3（NPHSNPAB） and Cd（NO_3）_2·4H_2O,and characterized by elemental analysis,infrared,UV-visible,fluorescence,thermal behavior and single-crystal X-ray diffraction. For this complex： C_（36）H_（42）Cd_2N_8O_（22）S_2,Mr = 1227.74,triclinic system,space group P1,a = 7.555（9）,b = 12.006（14）,c = 13.943（16） ？,α = 67.955（2）,β = 88.573（2）,γ = 77.550（2）o,V = 1142.5（2） ？~3,Z = 2,Dc = 1.784 g/cm^3,λ = 0.71073 ？,F（000） = 620,S = 1.125,R = 0.0460 and w R = 0.1159 for 3949 observed reflections with I 〉 2（I）. X-ray diffraction analysis reveals that the central Cd（Ⅱ） ion is bound by six oxygen atoms,forming a slightly distorted octahedral geometry. Density functional theory of complex 1 was studied. Noticeably,the application of 1 on metallic yarn got good effect.

Adsorption behavior and adsorption mechanism of Cu(Ⅱ) ions on amino-functionalized magnetic nanoparticles

Amino-functionalized magnetic nanoparticle （NH2-MNP） were prepared by a sol-gel approach. The adsorption behavior of Cu（II） ions on NH2-MNP was discussed systematically by batch experiments. The effects of initial Cu（II） ions concentration, time, pH and temperature were investigated. In kinetic studies, the pseudo-second-order model was successfully employed, and the pseudo-first-order model substantiated that Cu（II） adsorption on NH2-MNP was a diffusion-based process. Langmuir model and Dubinin-Radushkevich model （R2〉0.99） were more corresponded with the adsorption isotherm data of Cu（II） ions than Freundlich model. The adsorption capacity was increased with the increment of temperature and pH. NH2-MNP remains excellent Cu（II） recoveries after reusing five adsorption and desorption cycles, making NH2-MNP a promising candidate for repetitively removing heavy metal ions from environmental water samples. According to the results obtained from adsorption activation energy and thermodynamic studies, it can be inferred that the main adsorption mechanism between absorbent and Cu（II） ions is ion exchange-surface complexation.

Electrochemical reduction process of Co(Ⅱ) in citrate solution

Effects of citrate concentration and pH on the electrochemical reduction process of Co（Ⅱ） were investigated by cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS）. The results show that Co（Ⅱ） is reduced into two species which are free Co2＋ and [Co（C6H607）] in the solution composed of 0.05 mol/L CoS04·5H2O, 0.20 mol/L Na2SO4 and 0-0.40 mol/L C6H5O7Na3·2H2O in the pH range of 3-9. The reduction behavior depends on the pH of the solution. Co（H） is mainly reduced into the form of free Co^2＋ at pH 3 and into the form of [Co（C6H6O7）] at the pH range of 4-6 in citrate solution. The [Co（C6H6O7）] is first reduced to an intermediate state and then to Co°. Adsorption of the intermediate state exists on the surface of the electrode. Co（Ⅱ） is difficult to be reduced in the solution with the pH above 7, because the existing Co（Ⅱ）-citrate complex species [Co（C6H5O7）]- and [Co（C6H4O7）]2- are more difficult to be reduced than the hydrogen ion.

Thermodynamics analysis of LiFePO_4 pecipitation from Li-Fe(Ⅱ)-P-H_2O system at 298 K

Thermodynamics of the precipitation from Li-Fe（II）-P-H2O system at 298 K was investigated.The results demonstrate that LiFePO4 can be formed at room temperature under pH value of 0-11.3,and the impurities Li3PO4 and Fe（OH）2 will be yielded at pH value above 11.3 and 12.9,respectively.The optimum pH value for LiFePO4 precipitation is 8-10.5.Considering the low rate of phase transformation kinetics,metastable Li-Fe（II）-P-H2O system was also studied.The results indicate that equimolar ratio of co-precipitation precursor Fe3（PO4）2.8H2O and Li3PO4 cannot be obtained at the initial molar ratio 1：1：1 and 1：1：3 of Li：Fe：P.In contrast,equimolar ratio of the co-precipitation precursor can be yielded by adjusting the pH value to 7-9.2,matching the molar ratio 3：1：1 of Li：Fe：P,meaning that Li＋-excess is one of the essential conditions for LiFePO4 preparation by co-precipitation method.

Study on Adsorption of Hg(Ⅱ) by Chinese Walnut(Juglans mandshurica Maxim.) of Biomass Material

[Objective] The aim of the study was to make research on adsorption of Chinese walnut（Juglans mandshurica Maxim.） Shell（CWS） to Hg（Ⅱ） in water.[Method] Shells of Juglans mandshurica Maxim were used as biosorption to remove Hg（Ⅱ） in water solution to explore the influence to adsorption of Hg（Ⅱ） under different conditions,like pH solution,adsorption time,and Hg（Ⅱ）.[Result] The experimental results show that when absorptivity of Hg（Ⅱ） by CWS reached the highest,pH ranged within 5.0-6.0.The adsorptivity decreased as initial Hg（Ⅱ） concentrations increased.Fourier Transform Infrared Spectroscopy（FTIR） spectrum revealed some chemical groups of CWS may affect the adsorption of Hg（Ⅱ）,such as hydroxyl groups,methyl groups,aromatic methoxyl groups,unconjugated carbonyl,and typical aromatic ring,etc.Adsorption equation can be concluded considering the biosorption process relationship with Langmuir and Frendrich isotherm.[Conclusion] The study found that CW could be employed as a promising biosorption to remove Hg（Ⅱ） from aqueous environments.

Pb（Ⅱ）在Nafion修饰电极上的机理研究 （Ⅱ）富集过程中的离子交换和物理扩散

测定Ｐｂ（Ⅱ）在Ｎａｆｉｏｎ修饰电极上离子交换富集过程中的离子交换系数及物理扩散系数，提出了该过程中，Ｐｂ（Ⅱ）在Ｎａｆｉｏｎ膜中的浓度分布模型和Ｐｂ（Ⅱ）离子交换与扩散模式．

Selective separation of Cu(Ⅱ),Zn(Ⅱ),and Cd(Ⅱ)by solvent extraction

An experimental investigation was presented on the separation of Cu（Ⅱ）, Zn（Ⅱ）, and Cd（Ⅱ） from a rich sulfate leachate of zinc slag by solvent extraction. The results of orthogonal experiments indicate that LIX 984N is highly selective and very efficient in the extraction of Cu（Ⅱ）, and the analysis of variance indicates that the sequence of parameters according to their influence on the separation efficiency is phase ratio 〉 LIX 984N concentration 〉 pH value 〉 extraction time. The optimal condition for copper extraction is obtained as 25% of LIX 984N concentration, 7 rain of extraction time, 3：2 of phase ratio O/A, and pH = 1.7. The separation of Zn（Ⅱ） and Cd（Ⅱ） was performed after the copper extraction from the raffinate. Comparative analysis of the separation with di-2-ethylhexyl phosphoric acid （D2EHPA）, D2EHPA-tributyl- phosophate （TBP） synergistic extracting system, and 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester （HEHEHP） was made at pH = 2.0. It is demonstrated that the extraction efficiency with D2EHPA is improved after being saponified by sodium hydroxide, and D2EHPA-TBP synergistic extracting, as well as HEHEHP, has a superior selectivity to Zn（Ⅱ） over Cd（Ⅱ）.

1-Pyrenecarboxaldehyde thiosemicarbazone:A novel fluorescent molecular sensor towards mercury(Ⅱ) ion

A novel and simple fluorescent molecular sensor,1-pyrenecarboxaldehyde thiosemicarbazone（Hpytsc）,was synthesized.Its higher sensitivity and selectivity to mercury（Ⅱ） ion were studied through absorption and emission channels.The UV-vis spectra show that the increasing mercury（Ⅱ） ion concentrations result in the decreasing absorption intensity.The fluorescence monomer emission of Hpytsc is enhanced upon binding mercury（Ⅱ） ion,which should be due to the 1：1 complex formation between Hpytsc and metal ion.

Synthesis and Structural Characterization of a New Cadmium(II) Complex with a Double Betaine

A new flexible double betaine L （L = 1,4-bis（pyridinio-4-carboxylato-N-methyl）benzene, C20H16N2O4） and its cadmium（Ⅱ） complex [Cd（H2O）aL（NO3）]NO3.H2O 1 were synthesized. Complex 1 was obtained by self-assembly reaction of [Cd（NO3）2]-4H2O and L in hot water,and its crystal structure was determined by single-crystal X-ray diffraction analysis. Crystallographic data for complex 1： C20H24CdN4O14.H2O, Mr = 674.85, monoclinic, space group P21/c, a =13.7854（3）, b = 14.2820（3）, c = 14.9188（4） ,A°, β = 116.418（1）°, V = 2630.5（1）A°^3, Z = 4, Dc= 1.704g/cm^3,/J（MoKα） = 0.911 mm^-1, F（000） = 1368, the final R = 0.0315 and wR = 0.0768 for 3637 observed reflections with I 〉 2σ（I）. In complex 1, L acts as a monodentate ligand to link a Cd（Ⅱ） ion in a novel coordination mode of double betaines. The mononuclear [Cd（H2O）aL（NO3）] units are connected through intermolecular hydrogen bonds and π-π stacking reactions to generate a 3D network.

Removal of lead and cadmium ions by single and binary systems using phytogenic magnetic nanoparticles functionalized by 3-marcaptopropanic acid

The present research study is focused on green fabrication of superparamagnetic Phytogenic Magnetic Nanoparticles(PMNPs), and then its surface functionalization with 3-Mercaptopropionic acid(3-MPA). The resulting material(i.e. 3-MPA@PMNPs) characterized by FTIR, powder XRD, SEM, TEM, EDX, VSM, BET and TGA techniques and then further employed for the investigation of the adsorptive removal of lead(Pb^2+) and cadmium(Cd^2+) ions from aqueous solutions in single and binary systems. The material showed fastest adsorptive rate(98.23%) for Pb^2+ and(96.5%) Cd2+within the contact time of 60 min at pH 6.5 in the single system. The experimental data were fitted well to Langmuir isotherm, indicated monolayer adsorption of both metal ions onto 3-MPA@PMNPs and an estimated comparable adsorptive capacity of 68.41 mg·g^-1(Pb2+) and 79.8 mg·g^-1(Cd2+) at p H 6.5. However, kinetic data agreed well with pseudo-second-order model, and indicated that the removal mainly supported chemisorption and/or ion-exchange mechanism. Thermodynamic parameters such asΔGo,ΔHo, and ΔSo, were-3259.20, 119.35 and 20.73 for Pb^2+, and-1491.10, 45.441 and 7.87 for Cd^2+ at temperature 298.15 K, confirmed that adsorption was endothermic, spontaneous and favorable. The material demonstrated higher selectivity of Pb2+ and its removal efficiency was(98.20 ± 0.3)% in binary system experiments. The material persisted performance up-to seven(07) consecutive treatment cycles without losing their stability and offered comparable fastest magnetic separation(35 s) from aqueous solutions. Therefore, it is recommended that the prepared material can be employed to remove toxic heavy metal ions from water/wastewaters and this "green" method can easily be implemented at large scale in low economy countries.

Removal of Cadmium Ions from Aqueous Solution by Silicate-incorporated Hydroxyapatite

This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite, which were in favor of enhancing the cadmium ion sorption capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions.

Mechanically activated starch magnetic microspheres for Cd(Ⅱ)adsorption from aqueous solution

Magnetic starch microspheres(AAM-MSM)were synthesized via an inverse emulsion graft copolymerization by using mechanically activated cassava starch(MS)as a crude material,acrylic acid(AA)and acrylamide(AM)as graft copolymer monomers,and methyl methacrylate(MMA)as the dispersing agent and used as an adsorbent for the removal of Cd(Ⅱ)ions from aqueous solution.Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and vibrating sample magnetometry(VSM)were used to characterize the AAM-MSM adsorbent.The results indicated that AA,AM,and MMA were grafted to the MS,and the Fe_(3)O_(4) nanoparticles were encapsulated in the AAM-MSM adsorbent microspheres.The adsorbent exhibited a smooth surface,uniform size,and good sphericity because of the addition of the MMA and provided more adsorption sites for the Cd(Ⅱ)ions.The maximum adsorption capacity of Cd(Ⅱ)on the AAM-MSM was 39.98 mg·g^(-1).The adsorbents were superparamagnetic,and the saturation magnetization was 16.7 A·m^(2)·kg^(-1).Additionally,the adsorption isotherms and kinetics of the adsorption process were further investigated.The process of Cd(Ⅱ)ions adsorbed onto the AAM-MSM could be described more favorably by the pseudo-second-order kinetic and Langmuir isothermal adsorption models,which suggested that the chemical reaction process dominated the adsorption process for the Cd(Ⅱ)and chemisorption was the rate-controlling step during the Cd(Ⅱ)removal process.

Syntheses, Structures and Photoluminescence of the Cadmium(Ⅱ) and Copper(Ⅱ) Complexes Based on 4'-(4''-Pyridyl)-2,2':6',2''-terpyridine and 1,4-Benzenedicarboxylic Acid Ligands

Two new metal-organic complexes [Cd2（1,4-BDC）（4-pytyp）（H2O）4]·（1,4-BDC）（1） and [Cu2（1,4-BDC）（4-pytyp）2（H2O）2]·（1,4-BDC）·8H2O（2）（4-pytyp = 4＇-（4＇＇-pyridyl）-2,2＇：6＇,2＇＇-terpyridine, 1,4-H2 BDC = 1,4-benzenedicarboxylic acid） have been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared analysis and X-ray single-crystal diffraction. The scrutiny of single-crystal structure reveals that complex 1 forms to a 3D supramolecular network linked by π-π stacking interactions and hydrogen bonds. X-ray diffraction analysis reveals that complex 2 exhibits a 3D supramolecular network linked through complicated hydrogen bonds. The thermogravimetric analysis and photoluminescent properties of 1 and 2 are discussed in detail.

Synthesis and Crystal Structure of a Seven-coordinate Cadmium(Ⅱ) Complex

The reaction of 4-hydroxybenzoic acid (H2L),4, 4-diaminodiphenylmethane (DADPM) and Cd(NO3)2?H2O in methane/water gave rise to a seven-coordinate Cd(Ⅱ) complex [Cd2(HL)4(H2O)6]?H2O which has been characterized by single-crystal X-ray diffraction. The complex crystallizes in the orthorhombic system, space group Pna21 with unit cell parameters: a = 10.3352(3), b = 12.0481(3), c = 28.2016(1) ? V = 3511.65(13) 3, Z = 4, C28H36Cd2O20, Mr = 917.37, Dc = 1.735 g/cm3, F(000) = 1840, (MoK? = 1.29mm-1. The final R and wR are 0.0536 and 0.1086 for 4898 observed reflections with I ≥ 4(I). The Cd(Ⅱ) is seven-coordinated in a distorted pentagonal bipyramidal geometry. The inter-molecular hydrogen bonds lead to the formation of a two-dimensional layer structure.

Two Cd(Ⅱ) Coordination Polymers Based on a Flexible Tricarboxylate Ligand: Syntheses, Structures, and Photoluminescence and Catalytic Properties

Studies on the synthesis and design of coordination polymers(CPs) with flexible ligands are of great interest owing to their dynamic structures and promising applications. The title coordination polymers, {[Cd·(HTTTA)·(phen)]·2HO}n(1) and [Cd·(HTTTA)·(phen)]n(2)(H3 TTTA = 2,2’,2’’-[1,3,5-triazine-2,4,6-triyltris(thio)] tris-acetic acid, phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, IR, powder XRD and single-crystal X-ray diffraction. Complex 1 consists of one CdII ion, one HTTTA2-ligand and one phen co-ligand. The Cd(Ⅱ) metal clusters were bridged by the tridentate HTTTA2-ligands into infinite 1D chains, which are further connected into the 3D architecture by abundant hydrogen bonds. In 2, three carboxyl groups of HTTTA2-ligand show different coordination directions because of the C–S–C flexible bond angle, which leads to different 1D chains of 2. The strong π-π stacking interaction and four C–H···O hydrogen bonds connect the 1D chains into a 3D framework. The solid-state photoluminescence and catalytic properties were studied as well.

Crystal Structure and Characterization of a Binuclear Cd(Ⅱ) Quaternary Coordination Complex [Cd_2(phen)_2Q_2(BP)]_n(phen=1,10-Phenanthroline,BP = Biphenyl-4,4'-dicarboxylic acid,Q=8-Hydroxyquinoline Anion)

The structure of a binuclear cadmium（Ⅱ） quaternary complex, [Cd2（phen）2- Q2（BP）]n 1 （phen = 1,10-phenanthroline, BP = biphenyl-4,4′-dicarboxylic acid, Q = 8-hydroxy- quinoline-anion）, has been determined by X-ray crystallography and characterized by elemental analysis, IR spectrum and thermogravimetric analysis. It crystallizes in the monoclinic system, space group P21/n with a = 13.1906（18）, b = 10.9623（15）, c = 16.947（2）A, β = 111.3430（10）°, V = 2282.5（5）A^3, Z = 4, Mr = 556.85, Dc = 1.620 g/cm^3, F（000） = 1116,μ= 0.994 mm^-1 and S = 1.056. In the structure, 1D chains are connected via biphenyl-4,4′-dicarboxylic acid, 8-hydroxy quinoline anion and binuclear cadmium atoms into an infinite 1-D molecular chain architecture. Via aryl ring π-π stacking interactions a supramolecular structure is formed in 1.