STUDY ON THE COORDINATION COMPOUNDS OF RARE EARTHS WITH DIPEPTIDE-COORDINATION OF RARE EARTHS WITH DL-ALANYL-ALANINE

In this paper protonation constants of the title lisand and stability constants of its coordination compounds with rare earths have been determined by potentiometric titration at 25±0.1℃ and ionic strength of 0.10mol.dm^(-3)NaClO_4. The coordination of rare earths with DL-alanyl-alanine has been discussed. The stability of the coordination compound shows 'tetrad effect'. The position for yttrium shifts from its usual Bo-Er region to the vicinity of Tb.

Synthesis and Characterization of Rare Earth Complexes with Phthalanilic Acids and Amino Acids

The complexes with the general formula REP3A· H2O [P = 2- (COO ) C6H4CONHC6H4X, X=2-CI, 4-Br; A=Gly, Ala, Leu; RE=Pr3+, Nd3+] were synthesized and characlerized by elemental analysis, IR and reflectance electronic spectra and TG methods. The results show that rare earth ion in each complex is coordinated by three oxygen atoms. One is from the amido and the other two from the hydroxyl in the carboxylate and the amino acid respectively, and each complex contains one coordinate water molecule. Condon parameters Fk, Lande parameters(4f), Nephelanxetic ratio(β), percentage convalency parameter(δ) and bonding parameter(b ) of the chelates were calculated from the reflectance electronic spectra, indicating certain covalent character in the metalligand bond. The apparent decompose activation energies were evaluated and the decompose mechanism were discussed.

Synthesis，Crystal Structure and Infrared Spectrum of Lanthanum Dinuclear Coordination Compound with Alanine：〔La2（ala）4（H2O）8〕·（ClO4）6

Lanthanum coordination compound with l-alanine[La2（ala）4（H2O）8]·（ClO4）6（ala=l-alanine） was synthesized by reaction of lanthanum perchlorate with l-alanine in aqueous solution and obtained in the form of single crystals.The X-ray crystal structure has been determined and the IR spectrum has been studied.The title compound Cl6La2C12H44O40N4,Mr=1375.2,crystallizes in the triclinic,space group P1 , with parameters: a= 11.227（3）,b=11.445（2）,c=11.014（3）,α=114.46（2）,β=114.51（2）,γ=78.62（2）°,V=1171.73,Z=1,Dc=1.95 g/cm￣3,F（000）=680,μ=22.9 cm￣-1（MoKα）.The final R=0.050,Rω=0.051.In the crystal,two lanthanum ions are coordinated by four alanine molecules via four carboxylate bridges to form a dinuclear coordination compound.Four water molecules are coordinated to each lanthanum ion. There is a symmetric centre between the two lanthanum ions.The IR spectrum of the coordination compound and the relationship between the IR spectrum and the structure have been studied.The mechanism of the configuration inversion of alanine has been proposed.

STUDY ON SYNTHESIS,CHARACTERIZATION AND STRUCTURE OF A NEW RARE EARTH COORDINATION COMPOUND WITH BENZOIC ACID

In this paper,a new rare earth benzoate coordination compound,[TbL_3(HL)(H_2O)]_2 (HL=C_7H_6O_2=benzoic acid) is synthesized and characterized by elemental analysis DTA,TG,DTC,and IR spectra.The title compound crystallizes in triclinic,space.group P with a=9.148(1),b=11.460(2), c=13.506(2);α=112.76(1),β=91.83(1),γ=91.99(1)°;Z=1;V=1303.3.The final R factor is 0.0235.The rare earth ion is nine-coordinated to form a distorted monocapped square antiprism.

THE CRYSTAL STRUCTURE OF RARE EARTH COMPLEX WITH AMINO ACIDS Ⅱ The Crystal Structure of Gtutamate Comptex of Erbium Perchtorate

The crystat structure of {[Er;（L—Glu）;（H;O）;]（ClO;）;·3H;O);has been studied by X-ray diffraction. The crystal is monoctinic with space group P2;and cell parameters a=19.987（3） , b=16.505（3） , c=11.040（2） , β=104.69（1）;, V=3538（1） , Z=2, Dc=2.29 g. cm;, μ=53.2 cm;, F（000）=2384. The asymmetric unit contains two complex motecules and four centre ions. Each erbium （Ⅲ） is coordinated by five oxygen donors from four different glutamates and four oxygen donors from the aqua ligand to form a nine coordination potyhedron. The mean distances of Er—0 （carboxylate） and Er—Ow are 2.439 and 2.41 respectivety. The finat R and Rw are 0.043 and 0. 058, respectivety.

Syntheses of Coordination Compounds of 2-Amino-3-Methylbutanoic Acid Their Mixed Ligand Complexes and Antibacterial Activities

Coordination compounds of 2-amino-3-methylbutanoic acid were synthesized with chromium(III) and oxovanadium(IV) ions. M:L;1:2. Adducts of these complexes using 1,10-phenantroline and ethylenediamine were further synthesized, M:L, (1:2). These compounds were characterized using electronic, infra-red spectrophotometry, magnetic susceptibility measurement and percentage metal analyses. The zones of inhibition and minimum inhibitory concentrations of the compounds against eight microbes were studied. The results obtained indicated an octahedral geometry for the Cr(III) complexes, indicative of additional coordination of two water molecules. On the other hand a square pyramid geometry was obtained for the binary oxovanadium complex and its 1,10-phenantroline adduct. However, for the oxovanadium ethylenediamine adduct a distorted octahedral geometry was proposed. The result for the antibacterial studies indicated that both mixed ligand complexes of 1,10-phenantroline exhibited good antibacterial activity, and in some cases better activity than the standard, streptomycin.

Effects of Lanthanum on Liquid Culture and Contents of Amino Acids ofNostoc Commune Flagelliforme Cells

The effects of La(NO3)(3) on the liquid culture and the contents of amino acids of Nostoc commune flagelliforme cells were studied. It is indicated from the experimental results that the growth of Nostoc commune flagelliforme cells can be stimulated by La(NO3)(3) at the concentrations from 1 to 200 mg.L-1, and among them the treatment of 100 mg.L-1 La(NO3)(3) has the largest A(670) and dry weight which increased by 64.9% and 61.1%, respectively as compared with the control, and La(NO3)(3) can also influence the contents of some kinds of amino acids in Nostoc commune flagelliforme cells. The contents of aspartic acid and glutamic acid decreased by 59.9% and 57.9%, respectively, and that of proline increased by 24.5% with the treatment of 200 mg.L-1 La(NO3)(3).

Study of Complexes of Lanthanum with Amino Acids by Titration Calorimeter

The stability constants and thermodynamic functions for complexes of lanthanum with eight kind of amino acids according to 1∶1 and 1∶2 in proportion have been determined by titration calorimeter at 298.15 K. The enthalpy change makes a predominant contribution to the stability of these complexes. The ring in amino acid associated with lanthanum ion helps to enhance the stability of complexes. Steric effects between rings in complexes leads to that the equilibrium constants of reaction of the complexes (1∶2) is much less than that of the complexes (1∶1).

Crystal Structure and Characterization of a Novel Neodymium Coordination Compound Based on Dawson Cluster

A new coordination compound, [{Nd(NMP)_2(H_2O)_6Cl}{Nd(NMP)_2(H_2O)_7}H (P_2Mo_(18)O_(62)) (NMP=N-methyl-2-pyrrolidone) was synthesized and characterized by elemental analyses, IR spectrum, and X-ray single crystal structural analysis. The crystal structure indicates that the title compound belongs to monoclinic space group C _c, with unit cell dimensions a =2.4528(5) nm, b =1.9495(4) nm, c =2.4405(5) nm, β =109.94(3)°, Z =4, V =10.970 (4) nm^3, D _c=2.262 g·cm^(-3), R 1=0.0676, wR 2=0.1441. The ESR spectrum of powder of the title compound at 110 K after being exposed to sunlight shows the signal of Mo^(5+), g =1.95. Cyclic voltammetry was measured in aqueous solution containing 0.1 mol·L^(-1) KCl as the supporting electrolyte and shows that the title compound undergoes two one-electron reversible reductions.

Mobile Equilibrium Method for Determining Composition and Stability Constant of Coordination Compounds of the Form M_mR_n

A new method is proposed for determining the composition and stability constant of coordination compounds of the form M m R n ; it can be used to differentiate mono and poly nuclear coordination compounds. The equation derived is lg( A i/(A max - A i) m)=n lg c′ R+lg( m·β(c M/A max ) ( m -1) ). The method is based on Bent French limited logarithm method. The demonstration of the proposed method has yielded correct results for Sc 3+ chlorophosphonazo Ⅲ system and Fe 3+ Chromazurol S system.

Phase Chemistry of the Complexes of RE Amino Acids

Forty three phase diagrams of ternary system concerning rare earth salts, α amino acids and water, which were constructed by phase equilibrium methods, were expounded. The influences of the factors such as cations, anions, the structure of amino acids, temperature on the phase diagrams were discussed. Under the guidance of phase equilibrium results, over 150 new solid complexes were prepared. IR, reflecting, UV, FS, and Raman spectra for these complexes were investigated and the regularity of 'tripartite effect', 'tetrad effect', 'Nephelanxetic effect', 'Oddo Harkins' was observed. Thermal decomposition processes of the complexes were confirmed. Based on the comparison with the known crystal structures of rare earth amino acid complexes, an estimation method for predicting the crystal structure data of series complexes was founded. The constant volume combustion energies of the complexes were determined by RBC 1 type rotating bomb calorimeter. The standard enthalpies of combustion and standard enthalpies of formation were calculated for these complexes.

Synthesis and Characterization of Rare Earth Solid Complexes with Sodium 5-Aminosalicylate

Ten new rare earth solid complexes were synthesized by the reaction of sodium 5-aminosalicyliate with rare earth chloride. The structure character, physical and chemical properties of these complexes were studied by IR, UV, ()~1H NMR spectra, TG-DTA, fluorescence, elemental analyses, molar conductance and magnetic susceptibility. The ten rare earth complexes exist in dimeric form probably and the coordination number is seven. The antibacterial activity of the ligand and six complexes was also tested against Staphylococcus aureus, Escherichia coli and Bacillus subtilis, and the effect of Yb complex at 20 mg·ml^(-1) against Staphylococcus aureus is most significant.

Studies on the Adsorption of Amino Methylene Phosphonic Acid Resin for Holmium(Ⅲ)

The adsorption behavior and mechanism of a novel chelate resin, amino methylene phosphonic acid resin (APAR) for Ho(Ⅲ) were investigated. The statically saturated adsorption capacity is 258 mg·g^(-1) resin at 298 K in HAc-NaAc medium. The Ho(Ⅲ) adsorbed on APAR can be repeatedly eluted by 3.0 mol·L^(-1) HCl and the elution percentage is as high as 95.8%. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is k_(298)=1.14×10^(-5) s^(-1). The adsorption behavior of APAR for Ho(Ⅲ) obeys the Freundlich isotherm. The thermodynamic adsorption parameter, enthalpy change ΔH of APAR for Ho(Ⅲ) is 11.4 kJ·mol^(-1). The apparent activation energy is E_a=15.8 kJ·mol^(-1). The molar coordination ratio of the functional group of APAR to Ho(Ⅲ) is about 2∶1. The adsorption mechanism of APAR for Ho(Ⅲ) was examined by using chemical method and IR spectrometry.

Hydrothermal synthesis and structural studies of a new coordination polymer of lanthanum(Ⅲ) with benzene-1,2,4,5-tetracarboxylic acid and 4,4′-bipyridine

A new lanthanum complex formulated as {（bpyH2）[La（btc）（H2O）4（NO3）]·2H2O}n （1） （btcH4=benzene-1,2,4,5-tetracarboxylic acid; bpy=4,4＇-bipyridine） was hydrothermally synthesized. The complex was characterized by FT-IR spectroscopy, elemental analysis and X-ray diffraction. X-ray crystal structural analysis revealed that the compound belonged to the monoclinic space group C2/c with cell parameters a= 1.42806（7） nm, b=1.10258（5） nm, c=1.60333（8） nm and β=101.9400（10）°. The complex was polymeric with La^III atoms linked by four O atoms from two carboxylate groups of one benzene-1,2,4,5-tetracarboxylate. The LaIn atom was ten coordinated in a distorted tetracapped trigonal prism. In the crystal structure, a wide range of noncovalent interactions consisting of hydrogen bonding （of the types of O-H…O, N-H…O and C-H…O） and ion pairing interactions connected the various components into a supramolecular structure.

Influence of Structure and Reaction Conditions on Fluorescent Properties of Benzoic Acid Rare Earth Complexes

We synthesized a series of rare earth complexes with benzoic acid ramification containing different substitute groups or the same substitute group in different position; test the fluorescence property using fluorescence spectrometer of the complexes, and discussed the influence of different substitute group and the position of substitute group on the fluorescent properties of the rare earth complexes. The results showed that different substitute group and the position of substitute group on the benzene ring had important influence on the fluorescent properties of the benzoic acid rare earth complexes, when the other conditions were the same. The fluorescence effect of para-position ligand was better than ortho-position and meta-position ligand. For the benzoic acid complexes, their fluorescence intensity has relationship with the excellent absorption coefficient of the ligand and the high efficient ligand-to-trivalent rare earth ion energy transfer. Furthermore, when the ratio of Ln3+, ligand, phen was 1∶3∶1, the fluorescence properties of rare earth complex was the best.

Synthesis and Characterization of Lanthanum Complexes with Amino Acid Schiff Base

Six new complexes of lanthanum with amino acid Schiff base ligands, A-F, were prepared in methanol-aqueous solution. The composition and properties of the title complexes were characterized by elemental analysis, molar conductance, infrared, electronic spectra, H-1 NMR, thermogravimetric and differential thermal analysis.

Thermochemical Study on Coordination Complex of Neodymium Trichloroacetic Acid with 8-Hydroxyquinoline

Two coordinate reactions, NdCl 3·6H 2O(s) +3CCl 3COOH(s)( or TCA) =Nd(TCA) 3·3H 2O(s) +3HCl(g) +3H 2O(l) and Nd(TCA) 3·3H 2O(s) +2C 9H 7NO(s)= Nd(TCA)(C 9H 6NO) 2 (s) +2CCl 3COOH(s) +3H 2O(l), were studied by the classical solution calorimetry at 298.15K. The molar dissolution enthalpies of the reactants and the products in certain solvent (the first reaction in 1 mol·L -1 HCl, the second in a mixed solution consisting of absolute ethyl alcohol, dimethyl sulfoxide and 4 mol·L -1 HCl ) were measured by using an isoperibol calorimeter at 298.15K . From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(TCA) 3·3H 2O,s,298.15K] and [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] are determined as Δ fH m °[Nd(TCA) 3·3H 2O,s,298.15K]= -3053.3 kJ·mol -1 and Δ fH m° [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] = -1355.6 kJ·mol -1 .

Investigation on the Coordinate Structures of the Rare Earth Metal Complexes with Edta and Cydta Ligands

The crystal and molecular structures of cydta (trans-1, 2-cyclohexanediaminetetraacetic acid) have been determined by single\|crystal X-ray structure analyses. The reasons that RE Ⅲ -edta and RE Ⅲ -cydta complexes select different coordinate structures were discussed and illustrated through the comparison of the molecular and crystal structures between edta and cydta, (NH_ 4 )\[Y Ⅲ (edta)(H_ 2 O)_ 3 \]\55H_ 2 O and (NH_ 4 )\[Y Ⅲ (cydta)(H_ 2 O)_ 2 \]\55H_ 2 O as well as (NH_ 4 )\[Gd Ⅲ (edta)(H_ 2 O)_ 3 \]\55H_ 2 O and (NH_ 4 )\[Gd Ⅲ (cydta) (H_ 2 O) _ 2 \]\55H_ 2 O complexes.

Synthesis and Properties of Rare Earth Complexes with p-Methoxybenzoyl-Benzoylmethane and / or Amines

p-Methoxybenzoyl-benzoylmethane(HA)and its complexes LnA_4QH and LnA_3·xH_2O(for Ln=La～ Yb,Q=n-tributyl amine,diethyl amine,hexahydropyridine)were synthesized and characterized by elemental analysis,molar conductivity measurement,infrared spectroscopy,UV-visible absorption spectroscopy,thermal analysis and ~1H NMR spectra.Possibilities of using praseodymium and europium complexes as shift reagent are also discussed.

Solution-reaction Calorimetric Study of Coordination Compounds of Rare Earth Perchlorates with Alanine and Imidazole

Two coordination compounds of rare earth perchlorates with alanine and imidazole, [RE(Ala)n(Im)(H2O)]- (ClO4)3(s) (RE=La, n=3; RE=Nd, n=2), have been prepared and characterized. The standard molar enthalpies of reaction for the following two reactions, LaCl37H2O(s)+3Ala(s)+Im(s)+3NaClO4(s)=[La(Ala)3(Im)(H2O)]- (ClO4)3(s)+3NaCl(s)+6H2O(l) (1) and NdCl36H2O(s)+2Ala(s)+Im(s)+3NaClO4(s)=[Nd(Ala)2(Im)(H2O)]- (ClO4)3(s)+3NaCl(s)+5H2O(l) (2), were determined by solution-reaction calorimetry, at T=298.15 K, as 36.168±0.642 kJmol-1 and 48.590±0.934 kJmol-1 respectively. From the results and other auxiliary quantities, the standard molar enthalpies of formation of [La(Ala)3(Im)(H2O)](ClO4)3(s) and [Nd(Ala)2(Im)(H2O)] (ClO4)3(s) were derived, fmHD!{[La(Ala)3(Im)(H2O)](ClO4)3, s}=(-2984.8±1.0) kJmol-1 and fmHD! {[Nd(Ala)2(Im)(H2O)]- (ClO4)3, s}=(-2387.8±0.8) kJmol-1 , respectively.