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51.
Massue J Bellec N Chopin S Levillain E Roisnel T Clérac R Lorcy D 《Inorganic chemistry》2005,44(24):8740-8748
The reaction of tris(alkylthio)tetrathiafulvalene thiolates with 3-chloro-2,4-pentanedione affords tetrathiafulvalene (TTF) moieties substituted by the acetylacetone function (TTFSacacH), precursors of novel redox-active ligands: the acetylacetonate ions (TTFSacac). These TTFSacacHs have been characterized by X-ray diffraction analyses, and similar trends have been observed, such as a TTF core almost planar and the acetylacetone substituent located in a plane almost perpendicular to the plane formed by the TTF core. Their chelating ability has been demonstrated by the formation of the corresponding M(TTFSacac)2(pyridine)2 complexes in the presence of M(II)(OAc)2.H2O (M = Ni2+, Zn2+). These complexes with TTFSacac moieties, Ni(TTFSacac)2(pyridine)2, 6b, and Zn(TTFSacac)2(pyridine)2, 7b, have been characterized by X-ray diffraction analyses, showing in all structures the metal(II) center chelated by two TTFacac units in the equatorial plane and the octahedral coordination geometry around the metal completed by two axial pyridine ligands. Cyclic voltammetry and UV-visible-near infrared spectroscopic measurements have evidenced a sizable interaction between the two electroactive ligands and the stabilization of a mixed-valence state in the one-electron oxidized complexes. 相似文献
52.
53.
54.
Treatment of 2-methylphenols with chloro(diphenyl)-lambda(3)-iodane led to their regioselective dearomatizing 2-phenylation into cyclohexa-2,4-dienone derivatives via a proposed ligand coupling reaction. In the same vein of investigation, treatment of 2-methylanilines with the lambda(5)-iodane 2-iodoxybenzoic acid IBX reagent led to their regioselective dearomatization into previously undescribed ortho-quinol imines. 相似文献
55.
Abstract— Mutants of Saccharomyces cerevisiae with varying photodynamic sensitivities were isolated in an attempt to help identify the cytoplasmic targets of photodynamic action in yeast. 相似文献
56.
57.
A fluorogenic renin substrate, N-CBO-L -prolyl-L -phenylalanyl-L -histidyl-L -leucyl-L -leucyl-L -valyl-L -tyrosyl-L -seryl-β-naphthylamide, has been synthesized. Upon incubation at pH 5,6 with renin and an excess of the auxiliary enzyme aminopeptidase M, it gives rise to β-naphthylamine at a rate related to the quantity of renin. 相似文献
58.
Hauke Harms Julien Rime Olivier Leupin Stephan J. Hug Jan Roelof van der Meer 《Mikrochimica acta》2005,151(3-4):217-222
A luminescent bacterial biosensor was used to quantify bioavailable arsenic in artificial groundwater. Its light production
above the background emission was proportional to the arsenite concentration in the toxicologically relevant range of 0 to
0.5 μM. Effects of the inorganic solutes phosphate, Fe(II) and silicate on the biosensor signal were studied. Phosphate at
a concentration of 0.25 g L−1 phosphate slightly stimulated the light emission, but much less than toxicologically relevant concentrations of the much
stronger inducer arsenite. No effect of phosphate was oberved in the presence of arsenite. Freshly prepared sodium silicate
solution at a concentration of 10 mg L−1 Si reduced the arsenite-induced light production by roughly 37%, which can be explained by transient polymerization leading
to sequestration of some arsenic. After three days of incubation, silicate did not have this effect anymore, probably because
depolymerization occurred. In the presence of 0.4 mg L−1 Fe(II), the arsenite-induced light emission was reduced by up to 90%, probably due to iron oxidation followed by arsenite
adsorption on the less soluble Fe(III) possibly along with some oxidation to the stronger adsorbing As(V). Addition of 100 μM
EDTA was capable of releasing all arsenic from the precipitate and to transform it into the biologically measurable, dissolved
state. The biosensor also proved valuable for monitoring the effectiveness of an arsenic removal procedure based on water
filtration through a mixture of sand and iron granules. 相似文献
59.
H. R. Khan K. Lüders Ch. J. Raub G. Roth 《Zeitschrift für Physik B Condensed Matter》1980,38(1):27-33
Superconductivity, structure and electrical resistance behaviour of -phase alloys of Nb–Rh and Ta–Rh are investigated. The Ta–Rh alloys do not become superconducting above 1.2 K. The
andH
c2
(0) values of a homogeneous alloy with the composition Nb65.2Rh34.8 are 2.95 K, 13.9 kG/K and 23 kG, respectively, whereas for an inhomogeneous alloy with the composition Nb63.7Rh36.3 these values are 4.24 K, 5.5 kG/K and 14 kG, respectively. Splat quenching results in a substantial increase in the
andH
c2
(0) values of the Rh-rich sample. Annealing (900°C, 100 h) of the Rh-rich sample leads only to small changes in the superconducting properties but a small amount of Nb–Rh solid solution has been formed. The electrical resistance of Nb65.2Rh34.8 decreases with decreasing temperature and varies asT
0.5 between 150 and 240 K and asT between 60 and 140 K. For Ta70.0Rh30.0 the temperature coefficient changes to negative values below 170K. values are calculated for Nb–Rh using McMillan's formula. An estimatedT
c
value of Ta–Rh is 0.2 K. TheH
c2
(0) values of Nb–Rh are in good agreement with the theoreticalH
c
2**
(0) values.Dedicated to Prof. Dr. W. Buckel on the occasion of his 60th birthday 相似文献
60.
Le Gal J Tisato F Bandoli G Gressier M Jaud J Michaud S Dartiguenave M Benoist E 《Dalton transactions (Cambridge, England : 2003)》2005,(23):3800-3807
Twelve novel oxo-technetium and oxo-rhenium complexes based on N2S2-, N2SO- or N3S-tetradentate semi-rigid ligands have been synthesised and studied herein. By reacting the ligands with a slight excess of suitable [MO]3+ precursor (ReOCl3(PPh3)2 or [NBu4][99gTcOCl4]), the monoanionic complexes of general formula [MO(Ph-XN2S)]- could be easily produced in high yield. The complexes have been characterized by means of IR, electrospray mass spectrometry, elemental analysis, NMR and conductimetry. The crystal structures of [PPh4][ReO(Ph-ON2S)] 1b and [NBu4][99gTcO(Ph-ON2S)] 1c have been established. The [MO]3+ moiety was coordinated via the two deprotonated amide nitrogens, the oxygen and the terminal sulfur atoms in 1b and 1c. In both compounds, the ON2S coordination set is in the equatorial plane, and the complexes adopted a distorted square-pyramidal geometry with an axial oxo-group. The chemical and structural identity of the different prototypic complexes (rhenium, 99gTc complexes and their corresponding 99mTc radiocomplexes) have been also established by a comparative HPLC study. 相似文献