Chunji Niu

Study on the interaction of lanthanum(III) with adrenaline

Lanthanum(III) equilibria in the presence of adrenaline have been investigated by potentiometric titration under physiological conditions (37°C and an ionic strength of 0.15 M NaCl). The interaction of lanthanum(III) with adrenaline has also been studied using an ab initio method. The complex species in the lanthanum(III)–adrenaline system have been ascertained and the protonation constants for adrenaline and the stability constants for lanthanum(III) complexes with adrenaline have been obtained. Adrenaline can form stable lanthanum(III) complexes with the phenolic hydroxyl group of adrenaline as the binding site of lanthanum(III).

Synthesis and thermo-decomposition mechanism of rare earth complexes with phenylacetic acid

Rare earth complexes with phenylacetic acid (LnL(3) . nH(2)O, Ln is Ce, Nd, Pr, Ho, Er, Yb and Y, L is phenylacetate, n = 1-2) were prepared and characterized by elemental analysis, IR spectroscopy, chemical analysis, and X-ray crystal structure. The mechanism of thermal decomposition of the complexes was studied by means of TG-DTG, DTA and DSC. The activation energy and enthalpy change for the dehydration and melting processes were determined.

Computer simulation of Zn(II) speciation and effect of Gd(III) on Zn(II) speciation in human blood plasma

The speciation and distribution of Zn(II) and the effect of Gd(III) on Zn(II) speciation in human blood plasma were studied by computer simulation. The results show that, in normal blood plasma, the most predominant species of Zn(II) are [Zn(HSA)] (58.2%), [Zn(IgG)](20.1%), [Zn(Tf)] (10.4%), ternary complexes of [Zn(Cit)(Cys)] (6.6%) and of [Zn(Cys)(His)H] (1.6%), and the binary complex of [Zn(Cys)2H] (1.2%). When zinc is deficient, the distribution of Zn(II) species is similar to that in normal blood plasma. Then, the distribution changes with increasing zinc(II) total concentration. Overloading Zn(II) is initially mainly bound to human serum albumin (HSA). As the available amount of HSA is exceeded, phosphate metal and carbonate metal species are established. Gd(III) entering human blood plasma predominantly competes for phosphate and carbonate to form precipitate species. However, Zn(II) complexes with phosphate and carbonate are negligible in normal blood plasma, so Gd(III) only have a little effect on zinc(II) species in human blood plasma at a concentration above 1.0×10−4M.

Computer simulation for effect of Pr(III) on Ca(II) speciation in human interstitial fluid.

A mutiphase model of metal ion speciation in human interstitial fluid was constructed and the effect of Pr(III) on Ca(II) speciation was studied. Results show that Ca(II) mainly distributes in free Ca2+, [Ca(HCO3)], and [Ca(Lac)]. Because of the competition of Pr(III) for ligands with Ca(II), with the total concentration of Pr(III) rising, the percentages of free Ca2+, [Ca(Lac)] and [Ca(His)(Thr)H3], gradually increase and the percentages of CaHPO4(aq) and [Ca(Cit)(His)H2] gradually decrease. However, the percentages of [Ca(HCO3)] and CaCO3(aq) first increase, and then begin to decrease when the total concentration of Pr(III) exceeds 6.070×10−4M.

Tetra-μ-α-alanine-bis[tetraaquagadolinium(III)] hexaperchlorate

The title complex, [Gd(2)(C(3)H(7)NO(2))(4)(H(2)O)(8)](ClO(4))(6), contains centrosymmetric dimeric [Gd(2)(Ala)(4)(H(2)O)(8)](6+) cations (Ala is alpha-alanine) and perchlorate anions. The four alanine molecules act as bridging ligands linking two Gd(3+) ions through their carboxylate O atoms. Each Gd(3+) ion is also coordinated by four water molecules, which complete an eightfold coordination in a square-antiprism fashion. The perchlorate anions and the methyl groups of the alanine ligands are disordered.

Tetrakis(μ‐dl‐alanine‐O:O')octaaquadierbium(III) Hexaperchlorate

The structure of the title compound, [Er 2 (C 3 H 7 NO 2 ) 4 (H 2 O) 8 ](ClO 4 ) 6 , consists of dimeric [Er 2 (DL-alanine) 4 (H 2 O) 8 ] 6+ cations and perchlorate anions. The four alanine molecules act as bridging ligands linking two Er 3+ ions through their carboxyl O atoms. Each Er 3+ ion is also coordinated by four water molecules to complete eightfold coordination in a square antiprism fashion. The perchlorate anions and the methyl groups of the alanine ligands are disordered.

Computer simulation of Pr(III) speciation in human interstitial fluid

Abstract A multi-phase model of Pr(III) speciation in human interstitial fluid was constructed and Pr(III) speciation was studied. When the total concentration of Pr(III) is below 8.401 x10-10M, soluble Pr(III) species are main species. [Pr(Cit)](25.5%), [Pr(Cit)(Lac)](18.7%), [Pr(Cit)(Leu)](11.8%) and free Pr(III)(12.9%) are the most abundant species. When the total concentration of Pr(III) is between 1.583x10-9M and 4.000x10-3M, insoluble Pr(III) species are predominant species. Pr(III) is firstly bound to phosphate as precipitate of PrPO4, then carbonate as another precipitate of Pr2(CO3)3.

Hepta­aqua­tetra-μ3-hydroxy-hexa-μ2-l-leucine-(l-leucine)­tetraytterbium(III) tetrachlorozinc(II) tri­chloro­hydroxyzinc(II) tetrachloride octahydrate

The title bimetallic compound, [Yb4(mu3-OH)4(C6H13NO2)7(H2O)7][ZnCl4][ZnCl3(OH)]Cl4.8H2O, was synthesized at near physiological pH (6.0). The compound exhibits some novel structural features, including an asymmetric [Yb4(mu3-OH)4(L-leucine)7(H2O)7]8+ complex cation in which four OH groups act as bridging ligands, linking four Yb3+ cations into a Yb4O4 structural unit. Each pair of adjacent Yb3+ ions is further bridged by one carboxy group from a leucine ligand. Water molecules and a monodentate leucine ligand also coordinate to Yb3+ ions, completing their eight-coordinate square-antiprismatic coordination. The Yb4(mu3-OH)4(L-leucine)7(H2O)7]8+ cation, the [ZnCl4]2-, [ZnCl3OH]2- and Cl- anions, and the lattice water molecules are linked via hydrogen bonds.

Effect of Praseodymium(III) on Zinc(II) Species in Human Interstitial Fluid

A multiphase model of metal ion species in human interstitial fluid was constructed under physiological conditions. The effect of Pr(III) on Zn(II) species was studied. At the normal conditions, Zn(II) species mainly distribute in [Zn(HSA)], [Zn(IgG)], and [Zn(Cys)2H]+. With the Pr(III) level increased, the apparent competition of Pr(III) for ligands lead to the redistribution of Zn(II) species.