Two dimensional nuclear magnetic resonance analysis of bis(2,2 '-bipyridine)(2,2 '-bipyridine-4,4 '-dicarboxylic acid)ruthenium(II) hexafluorophosphate

The H-1 and C-13 nuclear magnetic resonance(NMR) spectra are reported for bis(2, 2'-bipyridine)(2, 2'-bipyridine-,4,4'-dicarboxylic acid) ruthenium(II) hexafluoruphosphate that has been used as a tagged molecule of electrochemiluminescent immunoassay. Because of the effect of Ru atom on ligands, it is difficult to assign its NMR spectra. BS' means of two dimensional H-1-H-1 COSY and H-1-C-13 COSY techniques, the H-1 and C-13 NMR spectra of bis (2, 2'-bipylidine) (2, 2'-bipyridine-4, 4-dicarboxylic acid) ruthenium(II) hexafluorophosphate are assigned completely. This provides a basis for NMR characterization of the nerv similar tagged molecules.

New optically active aromatic polyimides II: Synthesis and properties of optically active aromatic polyimide based on (R)-(+)-2,2 '-bis(2-trifluoro-4-aminophenoxy)-1,1 '-binaphthyl

Optically active (R)-(+)-2, 2'-bis(2-trifluoro-4-aminophenoxy)-1, 1'-binaphthyl was prepared from 1, 1'-bi-2-naphthol. The optically active aromatic polyimide was also successfully synthesized. This new polymer has good solubility, thermal stability etc. Its specific rotation was found to be +174 degrees, and its chiroptical property was also studied.

ELECTROCHEMICAL-BEHAVIOR OF BIS(2 /17-ARSENOTUNGSTATE) LANTHANATES AND THEIR ELECTROCATALYTIC REDUCTION FOR NITRITE

A series of new catalysts, K-14[Ln(As2W17O61)(2)]. xH(2)O (Ln = La, Pr, Sm, Eu, Gd, Tb, Dy, Tm and Yb) which can electrocatalyze reduction of nitrite are presented and their electrochemical behavior is described in this paper. Bis(2:17-arsenotungstate) lanthanates which are monovacant Dawson derivatives, exhibit two 2-electron and one 1-electron waves, attributed to electron addition and removal from the tungsten-oxide framework that comprises each anion structure. The formal potentials of redox couples are dependent on solution pH. Double-hump principle of formal potentials takes effect with increasing atomic number of lanthanide elements following their special electronic shell structure. The third waves of all the heteropolyanions have good electrocatalytic activities for nitrite reduction at pH 5.0.

A BIS(2,6-DI-TERT-BUTYL-4-METHYLPHENOLATO)-SAMARIUM(II) COMPLEX, [SM(OAR)2(THF)3]-THF

The title complex, bis(2,6-di-tert-butyl-4-methyl-phenolato-O)tris(tetrahydrofuran-O)samarium tetrahydrofuran solvate, [Sm(C15H23O)2(C4H8O)3].C4H8O, has distorted trigonal bipyramidal geometry around the Sm(II) atom. The 0(2), 0(3) and 0(4) atoms of the

EXTRACTION MECHANISM OF SC(III) AND SEPARATION FROM TH(IV),FE(III) AND LU(III) WITH BIS(2,4,4-TRIMETHYLPENTYL)PHOSPHINIC ACID IN N-HEXANE FROM SULFURIC-ACID-SOLUTIONS

The extraction equilibrium data of sulphuric acid and scandium(III) with bis(2,4,4-trimethylpentyl)phosphinic acid (H[BTMPP]) from sulphuric acid solutions have been obtained. There are two extraction mechanisms of scandium(III) with H[BTMPP] at different

SYNTHESIS AND CHARACTERIZATION OF HETEROPOLY BLUES OF BIS-2/17 MOLYBDOPHOSPHATE COMPLEXES WITH LANTHANIDE

Eight heteropoly blues of bis-2:17 molybdophosphate complexes with Lathanide, i.e., K17H2[Ln(P2Mo17O61)2] . nH2O and K17H4[Ln(P2Mo17O61)2] . nH2O were synthesized and characterized by elemental analyses potentiometric titration, IR, UV, polarography, cyclic voltammetry, X-ray photoelectron spectra X-ray powder diffraction, thermal analyses and ESR. Experimental results show that the properties of these series of heteropoly blues are different from those of their oxidized form, but no great changes in their structures were observed. The ligand P2Mo17O6110- remains alpha2-isomer's configuration.

STUDIES ON ORGANOLANTHANIDE COMPLEXES .40. SYNTHESIS AND X-RAY STRUCTURE OF BIS (2-METHOXYETHYLCYCLOPENTADIENYL) YTTRIUM AND YTTERBIUM TETRAHYDROBORATES

New bis (2-methoxyethylcyclopentadienyl) yttrium and ytterbium tetrahydroborates (Ln = Y, 1; Yb, 2) have been synthesized in good yield by the reaction of bis (2-methoxyethylcyclopentadienyl) lanthanide chlorides (Ln = Y, Yb) with sodium borohydride in THF at room temperature. The title complexes were characterized by elemental analyses, MS, H-1 NMR and IR spectra. The crystal structures of 1 and 2 have been determined by X-ray diffraction. 1 crystallizes from THF-n-Hexane in space group Pna2(1) with unit cell parametert: a = 1.2390(3), b = 1.1339(2), c = 1.1919 (2) nm and V = 1.6745(6) nm3 with z = 4 for D(c) = 1.39 g.cm-3.The structure was solved by direct method and refined to final R = 0.061 (for 1730 observed reflections). The Space group of 2 is Pna2(1) with unit cell parameters: a = 1.2399(6), b = 1.1371(5), c = 1.1897(2) nm and V = 1.6773(1) nm3 with z = 4 for D(c) = 1.72 g.cm-3, R = 0.038 (for 2157 observed reflections). The X ray structures and IR reveal the bidentate yttrium and ytterbium tetrahydroborate complexes with the intramolecular coordination bonds between lanthanide metal and ligand oxygen atoms.

Total synthesis of bis-(2,3-dibromo-4,5-dihydroxyphenyl)-methane as potent PTP1B inhibitor

Protein tyrosine phosphatase 1B (PTP1B) plays an important role as a negative regulator and has been proved to be an effective target for the treatment of type 2 diabetes mellitus. Bis-(2,3-dibromo-4,5-dihydroxyphenyl)-methane 7 was first reported as a natural bromophenol with significant inhibition against PTP1B which was isolated from red algae Rhodomela confervoides. Intrigued by its astonishing activity (IC50 = 2.4 mu mol/L), compound 7 was synthesized with the overall yield of 24% and evaluated for its PTP1B inhibitory activity compared with natural compound. (C) 2008 Li Jun Han. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Bis(2,3,5-triphenyltetrazolium) tetrachloridocadmate(II)

The title compound, ( C19H15N4)(2)[ CdCl4], a salt comprising two 2,3,5-triphenyl-substituted tetrazolium cations and a tetrachloridocadmate(II) anion, was synthesized by hydrothermal methods. In the anion, the Cd-II ion is tetrahedrally coordinated by four chloride anions. In the crystal structure, four cations and two anions pack into inversion-related subunits linked by C-H center dot center dot center dot Cl and offset pi-stacking interactions.Each of these subunits is surrounded by six others. Intermolecular pi-pi stacking interactions between phenyl rings are observed along the a axis, with perpendicular distances between the ring planes of 3.6015 and 3.6934 angstrom.

Comparative evaluation of 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) and 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2, 4-disulfophenyl)2H-tetrazolium, monosodium salt (WST-8) rapid colorimetric assays for antimicrobial susceptibility testing of staphylococci and ESBL-producing clinical isolates

A new generation of water soluble tetrazolium salts have recently become available and in this study we compared a colorimetric assay developed using one of these salts, 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2, 4-disulfophenyl)-2H-tetrazolium, monosodium salt (WST-8), with a previously developed 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide(XTT) colorimetric assay to determine which agent is most suitable for use as a colorimetric indicator in susceptibility testing. The MICs of 6 antibiotics were determined for 33 staphylococci using both colorimetric assays and compared with those obtained using the British Society for Antimicrobial Chemotherapy reference broth microdilution method. Absolute categorical agreement between the reference and test methods ranged from 79% (cefuroxime) to 100% (vancomycin) for both assays. No minor or major errors occurred using either assay with very major errors ranging from zero (vancomycin) to seven (cefuroxime). Analysis of the distribution of differences in the 1092 dilution MIC results revealed overall agreement, within the accuracy limits of the standard test ( 1 1092 dilution), using the XTT and WST-8 assays of 98% and 88%, respectively. Further studies on 31 ESBL-producing isolates were performed using the XTT method with absolute categorical agreement ranging from 87% (nitrofurantoin) to 100% (ofloxacin and meropenem). No errors were noted for either ofloxacin or meropenem with overall agreement of 91%. The data suggests that XTT is more reliable and accurate than WST-8 for use in a rapid antimicrobial susceptibility test. (c) 2007 Elsevier B.V. All rights reserved.

The stereoselective coordination chemistry of the helicating ligand N,N '-bis(-2,2 '-dipyridyl-5-yl)carbonyl-(S/R,S/R)-1,2-diphenylethylenediamine

Enantiomerically pure N,N'-bis(-2,2'-dipyridyl-5-yl)carbonyl-(S/R,S/R)-1,2-diphenylethylenediamine has been synthesised by linking two 2,2'-bipyridine units by (R,R)- and (S,S)-1,2-diphenylethylenediamine. The ligands possess a hindered rotation between the bipyridine chromophores, which are held together by intramolecular hydrogen bonds. ES mass spectroscopy confirmed that reaction with Fe(II), Co(III) and Cd(II) afforded dinuclear complexes. CD spectroscopy implied that enantiopure ligands conferred helicity to the metals centre giving a dominant triple helicate diastereoisomer (with the RR isomer giving a P helicate). H-1 NMR spectroscopy of the cadmium complex confirmed the presence of a single diastereoisomer. (C) 2003 Elsevier B.V. All rights reserved.

Stereoselective coordination chemistry of the tetradentate chelating ligand (2R,3R)-bis(2,2 '-dipyridyl-5-methoxyl) butane

The enantiomerically pure ligand L-3RR (2R, 3R)-bis(2,2'-dipyridyl-5-methoxyl) butane has been synthesised by linking two 2,2'-bipyridine units with (2R, 3R)-butandiol. The reaction of L-3RR with Zn(II) afforded a mononuclear species and the H-1 NMR spectroscopy points to a C-1 symmetry, expected for a distorted trigonal bipyramidal coordination environment. These observations were confirmed by MM2 calculations and electrospray mass spectrometry. The reaction of L-3RR with iron(II) indicated the formation of a dinuclear species by mass spectrometry. Solution state CD spectroscopy indicates that both complexes adopt a Lambda-configuration, implying a single stranded dinuclear iron(II) complex is present rather than the anticipated triple helical architecture.

Bis{2-[(2-hydroxyethyl)iminomethyl]phenolato}gold(III) tetrachloroaurate(III)

The title compound, [Au-III(C9H10NO2)(2)][(AuCl4)-Cl-III], contains [Au-III(C9H10NO2)(2)](+) cations and [(AuCl4)-Cl-III](-) anions with each of the gold(III) ions in a typical four-coordinate square-planar geometry. Both gold(III) metal centers are located on inversion centers.