A novel 2D arsenic vanadate network grafted with a transition metal complex: [Cu(phen)][(VV4As2O19)-V-IV-As-V]center dot 0.5H(2)O

A novel organic-inorganic hybrid compound [Cu(phen)](2)[(VV4As2O19)-V-IV-As-V-O-V].0.5H(2)O 1 has been hydrothermally synthesized. Its structure, determined by single crystal X-ray diffraction, exhibits an unusual two-dimensional arsenic vanadate layered network grafted with the [Cu(phen)](2+) complex. The chelating phen ligands project perpendicularly beyond the inorganic layer. Variable temperature magnetic susceptibility studies indicate that both ferro- and antiferro-magnetic interactions exist in 1.

From dissymmetrical mononuclear entities to centrosymmetrical heterotrinuclear complex with 2D supramolecular structure: synthesis, characterization, crystal structure, and magnetic properties

A new centrosymmetrical heterotrinuclear complex, {[Cu(oxbe)](2)Co(H2O)(2)}.2DMF.DMA with 2D supramolecular structure, has been obtained by the self-assembly of a dissymmetrical building block [Cu(oxbe)](-) with bivalent metal ion Co2+, where H(3)oxbe is dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)oxamido, DMF = dimethylformamide, DMA = dimethylamine. Its structure was determined by single crystal X-ray analysis. The molecular structure is centrosymmetrical with the cobalt atom lying on an inversion center. Through the hydrogen bonds and d-pi stacking interactions, a 2D supramolecular structure is formed. This study exemplifies a new method for the assembly of supramolecular structure using a dissymmetrical brick. Magnetic susceptibility measurements (5-300 K) indicate that the central cobalt and terminal copper metal ions are antiferromagnetically coupled with J = -23.1 cm(-1).

Evaluation of bioeffects of a long-term administering ChangLe on rat by proton NMR method and biochemical examination

High resolution H-1 nuclear magnetic resonance ( NMR) spectroscopy has been employed to assess long-term toxicological effects of ChangLe (a kind of rare earth complex applied in agriculture). Male Wistar rats were administrated orally with ChangLe at doses of 0, 0.1, 0.2, 2.0, 10 and 20 mg/kg body weight daily, respectively, for 6 months. Urine was collected at-day 30, 60, go and serum samples were taken after 6 months. Many low-molecular weight metabolites were identified by H-1 NMR spectra of rat urine. A decrease in citrate and an increase in ketone bodies, creatinine, DMA, DMG, TMAO, and taurine in the urine of the rats. receiving high doses were found by H-1 NMR spectra. These may mean that high-dosage of ChangLe impairs the specific region of liver and kidney, such as renal tubule and mitochondria. The decrease in citrate and the increase in succinate and alpha-ketoglutarate were attributed to a combination of the inhibition of certain citric acid enzymes, renal tubular acidosis and the abnormal fatty acid catabolism. The information of the renal capillary necrosis could be derived from the increase in DMIA, DMG and TMAO. The increase in taurine was due to hepatic mitochondria dysfunction. The conclusions were supported by the results of biochemical measure. merits and enzymatic assay.

Oxamido-bridged heterobinuclear copper(II)-nickel(II) complex and homotrinuclear nickel(II) complex with 2D supramolecular structure: synthesis, crystal structure, magnetic and spectroscopic properties

The oxamido-bridged heterobinuclear copper(II)-nickel(II) complex, [Cu(oxbe)Ni(phen)(2)]ClO4.3H(2)O (1) and homotrinuclear nickel(11) complex {[Ni(oxbe)](2)Ni(H2O)(2)}.2.5DMF (2) have been synthesized and characterized by means of elemental analysis, IR, EPR. and electronic spectra and magnetic susceptibility, where H(3)oxbe is dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)ox-amido, phen = 1.10-phenanthroline, DMF = dimethylformamide. Complex I has an extended oxamido-bridged structure consisting of planar copper(II) and octahedral nickel(II) ions. The chi(M) and mu(eff) versus T plots of 1 is typical of an antiferromagnetically coupled Cu(II)-Ni(II,) pair with a spin-doublet ground state, and magnetic analysis leads to J = -57.1 cm(-1). The molecular structure of 2 is centrosymmetrical, with one octahedral nickel atom lying at an inversion center and two terminal Ni(II) atoms in approximately square planar environment. Through the hydrogen bonds and pi- pi stacking interactions, a 2D supramolecular structure is formed.

Application of 2D Raman correlation spectroscopy to studing the effect of rare-earth Eu3+ on hemoglobin

The effect of rare-earth ion Eu3+ on hemoglobin (Hb) was studied by using two-dimensional Raman correlation spectroscopy. The results show that with the variation of Eu3+ concentrations as perturbation, the oxidation state of Hb and its spin state are both sensitive to the perturbation. Eu3+ added to Hb affects the oxidation and spin state synchronously. The four structure-sensitive bands of Hb are more accessible to the Eu3+ than other bands.

H-1 NMR analysis for metabolites in serum and urine from rats administrated chronically with La(NO3)(3)

H-1 NMR spectroscopy has been used to assess long-term toxicological effects of a rare earth. Male Wistar rats were administrated orally with La(NO3)(3) at doses of 0.1, 0.2, 2.0, 10, and 20 mg/kg body wt, resp., for 3-6 months. Urine was collected at 1, 2, and 3 months and serum samples were taken after 6 months. Numerous low-M-r metabolites in rats serum and rats urine, including creatinine, citrate, glucose, ketone bodies, trimethylamine N-oxide (TMAO), and various amino acids, were identified on 400- and 500-MHz H-1 NMR spectra. La3+-induced renal and liver damage is characterized by an increase in the amounts of the excreted ketone bodies, amino acids, lactate, ethanol, succinate, TMAO, dimethylamine, and taurine and a decrease in citrate, glucose, urea, and allantoin. Information on the molecular basis of the long-term toxicity of La(NO3)(3) was derived from the abnormal patterns of metabolite excretions. An assay of some biochemical indexes and analysis of some enzymes in plasma supported NMR results.

C-13 NMR谱图数据库相似检索的网上实现

本文对C-13 NMR谱图数据库相似检索的网上实现进行了研究。文章介绍了在网上实现C-13 NMR谱图数据库相似检索的方法以及提高相似检索效率的一些方法。

C-13 NMR study of ethylene/propylene/octene-1 terpolymers synthesized with TiCl4/MgCl2/i-Bu3Al as the catalyst

The theory of chemical shift effect of substituent was applied to the assignment of the C-13 NMR spectra of the ethylene/propylene and ethylene/octene-1 copolymers. Using the parameters derived above and the DEFT technique, we then entirely assigned the C-13 NMR spectra of the ethylene/propylene/octene(-1) terpolymers synthesized in the presence of the same heterogeneous supported Ziegler-Natta catalyst, TiCl4/MgCl2/i-Bu3Al. The present paper also covers the terpolymer composition and the monomer sequence distributions of a series of ethylene/propylene/octene-1 terpolymers.

Infrared and MAS NMR spectroscopic studies of Al18B4O33

The IR spectrum and B-11 and Al-27 MAS NMR spectra of Al18B4O33 are presented and discussed in relation to the possible existence of boron atoms substituting for aluminum atoms. The IR spectrum shows that the strong vibrations of the BO3 groups are present in the 1 500 similar to1 200 cm(-1) region, and very weak bands of BO4 units art present in the region from 1 000 to 1 100 cm(-1). B-11 MAS NMR spectrum indicates that the strong signal for BOB units appears in the region from delta +5 to delta +20, and the very weak signal for BO4 units is at about delta -1, while Al-27 MAS NMR spectrum shows five peaks at about delta +62, +42.1, +14, -4.7 and -6.4, originating from AlO4, AlO4, AlO5, AlO6 and AlO6, respectively, These results reveal that there are minor BO4 units in Al18B4O33, indicating that a small amount of B atoms substitute for Al atoms in the 4-fold coordination.

Recent progress in the studies of endohedral metallofullerenes

This overview presents the recent progress in the area of endohedral metallofullerenes in the past several years. The important results have been summarized as follows: (1) Many metals including Group 3 metals, most of the lanthanide series elements, and Group 2 metals have been encapsulated into a fullerene cage to form mono-, di-, and trimetallofullerenes by using the arc-evaporation technique. (2) Some endohedral metallofullerenes such as Group 3 metals, most of the lanthanide series elements, Group 2 metals, and some of their isomers have been successfully isolated and purified by a two-step or several-step HPLC technique. By using high-temperature and high-pressure extraction with pyridine, Ln@C-80, Ln@C-82, and Ln2@C-80 for most rare-earth metals have been selectively extracted in high yield (about 1% of the saw soot) from fullerenes and other size metallofullerenes. (3) The endohedral nature of metallofullerenes such as Y@C-82, Sc2@C-84, and Sc@C-82 has been finally confirmed by synchrotron X-ray powder diffraction. The symmetries and the structures of metallofullerenes such as Ca@C-82(III), La-2@C-80(I-h), Sc-2@C-84(D-2d), and Sc-2@C-84(C-s) have been confirmed by NMR measurements. (Lb) The information on the electronic structures and properties of endohedral metallofullerenes has been obtained by various spectrometric means Such as EPR, W-vis-MR, XPS, CV. It is generally accepted that three-electron transfer is favorable when M = Y, La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Lu but Sc, Eu, Sm, Yb, Tm, Ca, Sr, Ba prefer to donate two electrons to the fullerene cages. (5) Several chemical reactions of endohedral metallofullerenes have been reported in which reagents are disilacyclopropane, digermacyclopropane, diphenyldiazomethane, and trifluoroacetic acid. (6) Mass spectrometry provided the crucial evidence that led to the discovery of metallofullerenes in 1985 and has always played a key role in their identification and characterization, Ion-mobility measurements of gas-phase ions have obtained the information of structures and the formation mechanism of endohedral metallofullerenes. till Theoretical calculations on the endohedral metallofullerenes have made an important contribution to the studies on the symmetry of the cage, the position of metal atom(s) inside the cage, the number of electronic transfer between metal atom(s) and fullerene cage, etc. (C) 2000 Elsevier Science S.A. All rights reserved.

The characterization of comblike polymer electrolyte by means of NMR

The comblike polymers based on poly (styrene-co-maleic anhydride) backbone with poly (ethylene glycol) methyl ether as side chains were synthesized and characterized by H-1 NMR. with the result compared with that of 1R. It is found that it is both feasible and simple to synthesize this kind of compounds with the help of H-1 NMR.

环己烷~(13)C NMR化学位移的预测

通过计算机辅助方法对1 3 CNMR化学位移进行预测 .这个方法包括分子拓扑指数和几何参数特征值的计算及对所选特征进行的变量压缩 ,并对所选共振碳的化学位移与其提取的特征进行多元回归分析 ,从而得出其相关数学模型 .本文预测了环己烷中 45个仲碳原子的1 3 C化学位移 ,其标准误差约为 1 .4ppm.

NMR and UV-Vis study on phenyl-capped oligoaniline salts

Phenyl-capped oligoanilines in the oxidized state and their salts (by camphor sulfonic acid, CSA) were comparatively studied by UV-Vis and NMR spectroscopy. The UV-Vis spectra revealed a similar electron transfer behaviour and similar structure in the tetraaniline to those in polyaniline. Upon formation of the salt, H-1 NMR CH peaks of the oligomers showed large shifts to lower fields. The longer the molecule of a oligomer is, the more the shift, indicating that the charge brought into the N atoms by the proton was redistributed over the whole molecule. The CH and quaternary carbon peak-shifts support the electron cloud motion route H -->C -->C -->N -->H. This is in agreement with the four ring BQ derivatives model.

Two dimensional nuclear magnetic resonance analysis of ruthenium-(4,4'-dimethyl-2,2'-bipyridine)(2) (2,2'-bipyridine-4,4'-dicarboxylic acid) (PF6)(2)

The (1) H and C-13 NMR spectra are reported for Ru(4, 4'-dimethyl-2,2'-bipyridene)(2) (2,2'-bipyridine-4,4'-dicarboxylic acid) (PF6)(2) that can be used as a new electrochemiluminescent probe in immunoasssay and nucleic acid hybridization assay. Because of the effect ol:Ru atom ligands and complex steric configuration, it is difficult to attribute spectra of the title molecular, By using 2D (1) H-(1) H COSY and (1) H-C-13 HETCOR method, the proton and C-13 NMR spectra are assigned completely, which provides a satisfactory method to quantitative and qualitative, analysis of the title moleculer in the further study.

NMR relaxation studies of GdDTPA in human serum albumin solution

The water relaxation enhancement behavior of GdDTPA in human serum albumin (HSA) solution has been studied. The results indicate that GdDTPA can integrate noncovalently with HSA, mainly in forms of (GdDTPA)HSA and (GdDTPA),HSA, for which the apparent equilibrium constants are 0.05 mM(-1) and 0.02 mM(-2), respectively. (C) 1999 Elsevier Science Ltd. All rights reserved.