Syntheses and Properties of Tripicolinatechromium (Ⅲ)

Chromium (Ⅲ) has been implicated as glucose tolerance factor (GTF) in the maintenance of normal lipid and carbohydrate metabolism^[1]. Several organic chromium (Ⅲ) complexes containing nicotinate, amino acids ligand which have much higher biological activity than chromic chloride have been synthesized and extensively studied^[2]. Tripicolinatechromium (Ⅲ) as a new human chromium(Ⅲ) nutritional supplement was shown to reduce the symptoms of diabetes, hyperglycemia and cholesterol significantly^[3]. Although the crystal structure and NMR spectrum of tripicolinatechromium (Ⅲ) was studied previously^[4,5], Its properties have only received little attention. In this paper, we report the studies of syntheses and properties of tripicolinatechromium(Ⅲ).     

Crystal Structure and Spectroscopic Analysis of Polypyridyl Quinoxaline with Ce(Ⅲ) and Nd(Ⅲ)

Two high coordination crystals were obtained by the interaction of Ce~(3+) and Nd~(3+) with polypyridyl quinoxaline ligand 2,3,6,7,10,11-hexakis(2-pyridyl)dipyrazino[2,3-f:20,30-h]quinoxaline(HPDQ), and they were characterized. Complex 1 exhibits a 0 dimensional three-nuclear structure, with the three Ce(Ⅲ) atoms being ten-, eleven- and twelve-coordinated. Complex 2 is a 0 dimensional dual-core structure and the Nd(Ⅲ) atom is ten-coordinated. Complex 1 is of monoclinic system, space group P2/c with a = 16.850(3), b = 16.617(3), c = 24.017(5) ?, β = 100.94(3)o, V = 6602(2) ?~3, Z = 4, S = 1.062, F(000) = 3372, R = 0.0504 and wR = 0.1463(I 2σ(I)). Complex 2 adopts a monoclinic system, space group C2/c with a = 25.795(5), b = 20.166(4), c = 13.059(3) ?, β = 112.29(3)°, V = 6286(2) ?~3, Z = 4, S = 1.004, F(000) = 2664, R = 0.0663 and wR = 0.1821(I 2σ(I)). Furthermore, the behaviors of HPDQ with Ce~(3+) and Nd~(3+) in the solution are also investigated. After the Ce~(3+) is added, the ultraviolet absorption of the solution is enhanced with a red shift compared with that of the HPDQ ligand. While after adding Nd~(3+), the ultraviolet absorption of the solution is weakened, and it has a red shift which is the same as Ce~(3+). However, after the respective addition of metal ions, the emission of all solutions is quenched and has a red shift compared with that of the HPDQ ligand.     

Synthesis and relaxivity of Gd(Ⅲ), Fe(Ⅲ) and Mn(Ⅱ) complexes with dihydropyridine derivative of diethvlenetriaminepentaacetic acid

A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex, which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging.     

Structures and Photoluminescent Properties of 3D Ho(Ⅲ) and Y(Ⅲ) Complexes with 2,4,6-Pyridinetricarboxylate

Two 3D rare earth coordination polymers {[Ho(ptc)(H_2O)_(2.5)]·0.5 H_2O}n(1) and {[Y2(ptc)2(H_2O)_5]·H_2O}n(2)(H_3ptc = 2,4,6-pyridinetricarboxylic acid) have been synthesized with Ho(Ⅲ) or Y(Ⅲ) chloride and H_3ptc by hydrothermal method. The X-ray structure analyses display the two complexes are isomorphic and crystallize in monoclinic crystal system with P21/n space group for 1 and P21/c space group for 2. Ho(Ⅲ) and Y(Ⅲ) both show two different coordination modes. One is nine-coordinated and forms a distorted tricapped trigonal prism and the other is eight-coordinated to get a distorted bicapped trigonal prism. The ptc3-also shows two different coordination modes by connecting four or three rare earth ions. The photoluminescent properties of 2 show that it can emit blue fluorescence at 440 nm with excitation at 335 nm. The fluorescence lifetime of 2 is 1.64 μs and the absolute fluorescence quantum yield is 10.2%.     

Synthesis and Structure of Dibenzoyl-bissemicarbazone Neodymium(Ⅲ) Perchlorate

A new Schiff base Dibenzoyl-bissemicarbazone C15H16N6O2(L) and its complex with neodymium(Ⅲ ) perchlorate [NdL2(H2O)2](ClO4)3 were synthesized. The crystal and molecular structure of the title complex were determined by single crystal X-ray diffraction. The crystal is monoclinic and conforms to space group P. with cell constants a=10. 893(2) A, b= 12. 118(3) A , c=22. 494(5) A , β=89. 86(3)% V = 2969.19A3. The final standard deviation R=0. 0919. In the complex Nd is coordinated by four nitrogen and six oxygen atoms, of which four nitrogen and four oxygen atoms are provided by two neutral ligands L, and the other two oxygen atoms are provided by two water molecules, forming a ten-coordinated complex cation, which the perchlorate groups exist in the outer sphere. The coordination polyhedron takes a bicapped anti-square prism arrangement. That the average bond length of Nd-N is 2. 735 A indicates that the coordination of N in groups to Nd( Ⅲ ) is very weak.     

Separation of Samarium(Ⅲ) and Gadolinium(Ⅲ) by A Push-pull Liquid Membrane System

ＳｅｐａｒａｔｉｏｎｏｆＳａｍａｒｉｕｍ（Ⅲ）ａｎｄＧａｄｏｌｉｎｉｕｍ（Ⅲ）ｂｙＡＰｕｓｈ┐ｐｕｌＬｉｑｕｉｄＭｅｍｂｒａｎｅＳｙｓｔｅｍＹＡＮＧＧｕａｎｇ－ｈｕｉ＊（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ,ＥｄｕｃａｔｉｏｎＣｏｌｅｇｅｏｆＪ...     

Synthesis and Crystal Structure of Cobalt(Ⅲ) Tris(diethyldithiocarbamato) Complex

1INTR0DUCTI0NRecently,thedesignandsynthesisofdinuclearcomplexeshavebeenafascinat-ingareaofresearchowingt0theirimportanceinbasicandappliedchemistry"'.Par-ticularintersthasdevelopedindinuclearcomplexesasmodelsformeta1loproteins"'.Inanattempttosynthesizethetypeof[Ln(S,CN(C2H,)2)3j[Co(S2CN(C2H5)2)2jdinuc1earcomplex,thepurefinecrystalsofCo[S2CN(C2H5)2)2)3were0btained.2EXPERIMENTAL2'1Preparation0fC0[S,CN(C,H,),j,TotheclearsolutionoftheanhydrousSmCl3(0.5mmol)in5mLanhydrousethanolw…     

Synthesis and Characterization of 2-Decyl-DTPA and Its Gd(Ⅲ) Chelate

IntroductionGadoliniumchelatesareveryimportantbecauseoftheirpotentialbiologicalapplicationsintheareaofmagneticresonanceimaging(MRI) .Thegadoliniumchelateofdiethylenetriaminepentaaceticacid(DTPA )wasthefirstMRIcontrastagentinclinicaluse .How ever,Gd DTPA ,asanextracellularcontrastagent,hasnoliver specificity .Theintroductionofanaddi tionallipophilicsubstitutenttoanyoneofthefivemethylenesoftheaceticacidresiduesortoanyoneofthefourcarbonatomsofthebackboneinDTPAmaychangethetissuespecificity…     

Synthesis and Characterization of 2-Decyl-DTPA and Its Gd(Ⅲ) Chelate

The present paper covers the synthesis and the characterization of ligand 2-decyl-3, 6, 9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid, H5L, and its Gd(Ⅲ) chelate. The protonation constants for H5L(lgKHi=10.90, 8.50, 4.55, 2.92, 2.20) and the stability constant for GdL2- (lgKGdL2-=22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA, respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after the introduction of a linear chain decyl group into the terminal acetic acid residue of DTPA. The Gd(Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging(MRI).     

Synthesis and reactivity of carbazole-containing hypervalent iodine(Ⅲ) reagents

A range of bench-stable carbazole-containing hypervalent iodine(Ⅲ) reagents were synthesized by I-N bond formation in good yields.This kind of benziodoxolone reagents was used for a C-N coupling reaction to introduce a carbazole group to aromatic heterocycle compounds.     

Syntheses and Magnetism of Binuclear Tb(Ⅲ)-Tb(Ⅲ)Complexes with Dianion of Chloranilic Acid as Bridging Ligand

The syntheses, spec(?) complexes are of significance for understanding mechanisms of magnetic interaction between metal ions and the exploitation of the synthesis of molecular magnetic materials. There were a few works reported previously on the syntheses and magnetic in-     

Electrochemical Co-reduction of Bi(Ⅲ)and Y(Ⅲ)and Extracting Yttrium from Molten LiCl-KCl Using Liquid Bi as Cathode

The electrochemical reaction of Bi(Ⅲ)and co-reduction behaviour of Bi(Ⅲ)and Y(Ⅲ)ions were researched in molten LiCl-KCl on a ttmgsten(W)electrode employing a range of electrochemical teclmiques.Cyclic voltammetric and square-wave voltanunetric results revealed that the reduction of Bi(Ⅲ)was a one-step process,with the exchange of three electrons on a W electrode,and diffusion-controlled.The electrochemical curves showed two reduction peaks pertaining to the formation of Bi-Y alloy compounds,because of the co-reduction of Bi(Ⅲ)and Y(Ⅲ) by metallic Y deposited on the pre-deposited Bi-coated W electrode and reacting with Bi metal in molten LiCl-KCl. Furthermore,galvanostatic electrolysis was conducted using liquid Bi as cathode to extract yttrium at different current intensities,and the extractive products were analyzed by SEM,EDS and XRD.The results indicated that BiY intermetallic compotmd was formed in the molten LiCl-KCl-YCl3 system.     

Synthesis and magnetism of μ-isophthalato dinuclear lanthanide(Ⅲ) complexes

Seven new μ-isophthalato dinuclear lanthanide(Ⅲ) complexes, namely [Ln2(IPHTA)(Me2-phen)4-(ClO4)2](ClO4)2 (Ln = La, Nd, Sm, Eu, Gd, Ho, Er), where Me2-phen denotes 2,9-dimethyl-1, 10-phenanthroline (Me2-phen) , IPHTA represents isophthalate dianion, have been synthesized and characterized by elemental analyses, molar conductance measurements, IR, ESR and electronic spectra. The variable-temperature magnetic susceptibilities of [Gd2( IPHTA) (Mez-phen)4 (ClO4)2] (ClO4)2 complex were measured in the temperature range of 4-300 K and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H = - 2JS1 · S2, giving the exchange parameter J =- 0.19 cm-1 . This result is commensurate with a weak antiferromagnetic spin-exchange interaction between Gd(Ⅲ)-Gd(Ⅲ) ions within the complex.     

Structure and magnetic properties of homobinuclear gadolinium (Ⅲ) complex of isonicotinoyl hydrazone

The crystal structure of [Gd2(μ-L)3(H2O)2].1.5(NO3).1.5 (OH)-5H2O (where L is an-ion of N, N'-Diisonicotinoyl-2-hydroxy-5-methyl-isophthalaIdehyde dihydrazone) has been determined by X-ray diffraction method. The complex crystallizes in the monoclinic system, space group P21/c with a=1.6654(3), b=1.6904(3), c=2.8039(6) nmβ=91.30(3)°, final R factor is 6.3%. The structrue consists of [Gd2(μ-L)3(H2O)2]3+ cation, one and a half nitrate and 1.5 hydroxyl anions and five water molecules. Within dinuclear cation, Gd(Ⅲ)-Gd(Ⅲ) is bridged by oxygen and nitrogen atoms of the three ligands, resulting in Gd...Gd distance of 0.36353(2) nm. Gd(Ⅲ) exhibits a distorted 1333 stack coordination environment. Magnetic susceptibility measurements in the temperature range 300-4 K revealed the occurrence of weak antiferromagnetic exchange interaction between two Gd(Ⅲ) ions with a J value of -0.22, and g of 1.93.     

Stability and Luminescence Properties of Tb (Ⅲ) Complexes with Adrenaline

Theinteractionofrareearthwithhormoneshouldbestudiedindetailinordertoexploremechanismoftheneuralandendocrineeffectofrareearth.Asacontinuationofourresearchontheinteractionofrareeafthwithhormone',stabilityandluminescencepropertiesofTb(lII)complexeswithadrenalineorepinephrine(3,4-dihydroxy-a(methylaminomethyl)benzylalcohol,(HO)zCeH3CH(OH)CH=NHCHshavebeenstudiedinthiswork.Satisfactoryresultshavebeenobtained.PotentiometrictitrationsweremadeonapHS-3CpHmeterbymeansofthemethoddescribedinpreviou…     

Simultaneous Determination of Gold(Ⅲ) and Copper(Ⅱ) with Two-Way Stripping Voltammetry

The simultaneous determination of Au(Ⅲ) and Cu(Ⅱ) by atomic absorption spectrometry^[1,2], X-ray fluorescence^[3] and differential-pulse polarography^[4] have been reported. The apparatus used in spectrochemical analysis are complex and expensive. The method reported in reference^[4] involves a poisonous electrode-DME(dropping-mercury electrode) and unsatisfied performance with the detection limit. We had reported the determination of trace Au(Ⅲ) or Cu(Ⅱ) by a sensitive tripping voltammetry with solid electrode^[5], but there is no report about the simultaneous determination of trace Au(Ⅲ) and Cu(Ⅱ) by stripping voltammetry ever since.     

Preparation and Characterization of Chromium ( Ⅲ )-Containing α-and β-Tungstosilicates( Ⅱ )

Two new compounds of A- type α-and β-K4.5H2.5[SiW9Cr3(OH2)3O37]·xH2O were synthesized. The two kinds of isomers of α-and β-SiW12-xCrx(x=2, 3) were identified by Second-derivative IR spectroscopy and cyclic voltammetry. The numbers of electrons involved in reductions were obtained by controlled potential electrolyses of the isomers.     

Theoretical studies on the complexation of Eu(Ⅲ) and Am(Ⅲ) with HDEHP: structure,bonding nature and stability

Separation of trivalent lanthanides(Ln(Ⅲ)) and actinides(An(Ⅲ)) is a key issue in the advanced spent nuclear fuel reprocessing. In the well-known trivalent actinide lanthanide separation by phosphorus reagent extraction from aqueous komplexes(TALSPEAK) process, the organophosphorus ligand HDEHP(di-(2-ethylhexyl) phosphoric acid) has been used as an efficient reagent for the partitioning of Ln(Ⅲ) from An(Ⅲ) with the combination of a holdback reagent in aqueous lactate buffer solution. In this work, the structural and electronic properties of Eu~(3+) and Am~(3+) complexes with HDEHP in nitric acid solution have been systematically explored by using scalar-relativistic density functional theory(DFT). It was found that HDEHP can coordinate with M(Ⅲ)(M=Eu, Am) cations in the form of hydrogen-bonded dimers HL_2~-(L=DEHP), and the metal ions prefer to coordinate with the phosphoryl oxygen atom of the ligand. For all the extraction complexes, the metal-ligand bonds are mainly ionic in nature. Although Eu(Ⅲ) complexes have higher interaction energies, the HL_2~- dimer shows comparable affinity for Eu(Ⅲ) and Am(Ⅲ) according to thermodynamic analysis, which may be attributed to the higher stabilities of Eu(Ⅲ) nonahydrate. It is expected that this work could provide insightful information on the complexation of An(Ⅲ) and Ln(Ⅲ) with HDEHP at the molecular level.     

Effects of Y (Ⅲ) Ions on the Fluorescence Properties of Ce(Ⅲ) Ion and the Organic Ligands in the Complex

The enhancement effects of Y ( Ⅲ) ions on the fluorescence of Ce ( Ⅲ) in Ce ( Ⅲ)-Y ( Ⅲ)-PMMA (polymethylmethacrylate ) or Ce ( Ⅲ)-Y ( Ⅲ)-PVC (polyvinyl chloride ) complex systems were observed. The influence of Y ( Ⅲ) ions on the emission spectra of PMMA ligands in PMMA-Y ( Ⅲ) and the fluorescent enhance- ment of Y( Ⅲ) on Ce( Ⅲ) emission in PMMA-Ce-Y by Y( Ⅲ) ion were studied. It was also of interest to note that when Y ( Ⅲ) ions were added into PMMA and into bpy(bipyridine ), respectively, the emission spectrum of PMMA ligands was split into fine structure bands by Y ( Ⅲ), and the fluorescence intensities of bpy ligands in bpy-Y ( Ⅲ) complexes were considerably increased.     

Kinetics and Mechanism of the Oxidation of Glycol by Dihydroxyditelluratoargentate(Ⅲ) with Spectrophotometry

The kinetics of the oxidation of glycol by dihydroxyditelluratoargentate (Ⅲ) complex(DDA) was studied in alkaline medium with spectrophotometry(in a temperature range of 16.6-40 ℃).The first-order rates with respect to glycol and Ag(Ⅲ) were all found.The rates increased with the increase in [OH-] and decreased with the increase in [TeO2-4].No effect was found with the addition of KNO3 and no free radical was detected.In view of this,the dihydroxymonotelluratoargentate(Ⅲ) species(DMA) is assumed to be the active species.A plausible mechanism involving a two-electron transfer is proposed,and the rate equation derived from the mechanism can explain all experimental observations.Activation parameters of the rate-determining step and constants are evaluated.