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1.
Yu. V. Vasil’ev R. R. Abzalimov Sh. K. Nasibullaev R. F. Tuktarov F. Hauke U. Reuther A. Hirsch T. Drewello 《Physics of the Solid State》2002,44(3):554-556
The formation and decay of negative molecular ions of azafullerenes and their hydrogenated derivatives are investigated by mass spectrometry. The mechanisms of resonant electron capture and the lifetimes of negative molecular ions with respect to the electron autodetachment in azafullerene molecules are discussed. A comparative analysis of the data obtained for azafullerenes and hydrogenated fullerene derivatives is carried out. 相似文献
2.
3.
Hanns‐Dieter Amberger Lixin Zhang Hauke Reddmann Christos Apostolidis Olaf Walter 《无机化学与普通化学杂志》2006,632(15):2467-2470
Electronic Structures of Organometallic Compounds of f Elements. 64 Does the Zwitterionic Nature of the Triphenylphosphine Oxide Ligand Manifest itself in its Spectrochemical Properties? The triphenylphosphine oxide mono adducts of the moiety tris(η5‐cyclopentadienyl)lanthanide(III) (Ln(Cp)3; Ln = Pr ( 1 ), La ( 2 )) were synthesized and structurally characterized. The Ln–O distances of these compounds are noticeably shorter than those of the corresponding THF adducts. A crystal field (CF) analysis of the optical spectra of 1 leads to a low absolute value of the quadratic CF parameter which is comparable with those of [Pr(Cp)3(L)]? adducts with anionic bases but not with [Pr(Cp)3(MeTHF)]. Reasons for the latter finding are presented. 相似文献
4.
Mona Wells Michael Gösch Hauke Harms Jan Roelof van der Meer 《Mikrochimica acta》2005,151(3-4):209-216
This paper describes the development of an analytical technique for arsenic analyses that is based on genetically-modified
bioreporter bacteria bearing a gene encoding for the production of a green fluorescent protein (gfp). Upon exposure to arsenic
(in the aqueous form of arsenite), the bioreporter production of the fluorescent reporter molecule is monitored spectroscopically.
We compared the response measured as a function of time and concentration by steady-state fluorimetry (SSF) to that measured
by epi-fluorescent microscopy (EFM). SSF is a bulk technique; as such it inherently yields less information, whereas EFM monitors
the response of many individual cells simultaneously and data can be processed in terms of population averages or subpopulations.
For the bioreporter strain used here, as well as for the literature we cite, the two techniques exhibit similar performance
characteristics. The results presented here show that the EFM technique can compete with SSF and shows substantially more
promise for future improvement; it is a matter of research interest to develop optimized methods of EFM image analysis and
statistical data treatment. EFM is a conduit for understanding the dynamics of individual cell response vs. population response, which is not only a matter of research interest, but is also promising in the practical terms of developing
micro-scale analysis. 相似文献
5.
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
6.
Bonhommeau S Bréfuel N Pálfi VK Molnár G Zwick A Salmon L Tuchagues JP Sanchez Costa J Létard JF Paulsen H Bousseksou A 《Physical chemistry chemical physics : PCCP》2005,7(15):2909-2914
A quasi-quantitative photo-induced low-spin (LS)-->high-spin (HS) conversion of FeII ions has been observed in the [Fe(TRIM)2]Cl2 complex by irradiating the sample with blue light (488 nm) at 10 K. The time dependence of the HS-->LS relaxation has been studied between 10 K and 44 K by means of magnetic susceptibility measurements. These relaxation curves could be satisfactorily fitted by mono-exponential decays including tunnelling effect except for temperatures below 30 K. The introduction of a distribution of vibrational frequencies into this model improved significantly the fits in the low-temperature range and gave a good agreement with the experimental data in the whole temperature range suggesting a multi-rate relaxation process in this complex. 相似文献
7.
Two New Silicate-Chlorides with Divalent Europium: LiEu3[SiO4]Cl3 and Li7Eu8[SiO4]4Cl7 LiEu3[SiO4]Cl3 was prepared by reaction of LiCl with Eu2SiO4 and Li7Eu8[SiO4]4Cl7 from Li with Eu2O3, SiO2 and LiCl. The crystal structures of LiEu3[SiO4]Cl3 (Pmna, a = 946.95(13); b = 699.52(8); c = 1 368.0(2) pm; Z = 4; R1 = 0.0325, R2w = 0.0642) and Li7Eu8[SiO4]4Cl7 (P21/c; a = 851.85(5); b = 948.62(7); c = 1 679.0(2) pm; β = 96.221(8)°; Z = 2; R1 = 0.0352, R2w = 0.0744) were determined from four-circle diffractometer data. LiEu3[SiO4]Cl3 contains [Li(SiO4)2] units and LiCl6 octahedra while in Li7Eu8[SiO4]4Cl7 larger ?lithosilicate”? groups are found. In both structures, the Eu2+ ions are coordinated mostly eightfold by O2? and Cl? ligands. 相似文献
8.
9.
Vijayanand Chandrasekaran Eugen Johannes Hauke Kobarg Frank D S?nnichsen Thisbe K Lindhorst 《ChemistryOpen》2014,3(3):99-108
Spatial orientation of carbohydrates is a meaningful parameter in carbohydrate recognition processes. To vary orientation of sugars with temporal and spatial resolution, photosensitive glycoconjugates with favorable photochromic properties appear to be opportune. Here, a series of azobenzene glycosides were synthesized, employing glycoside synthesis and Mills reaction, to allow “switching” of carbohydrate orientation by reversible E/Z isomerization of the azobenzene N=N double bond. Their photochromic properties were tested and effects of azobenzene substitution as well as the effect of anomeric configuration and the orientation of the sugars 2-hydroxy group were evaluated. 相似文献
10.
Dr. Sunewang R. Wang Dr. Merle Arrowsmith Julian Böhnke Prof. Dr. Holger Braunschweig Dr. Theresa Dellermann Dr. Rian D. Dewhurst Hauke Kelch Dr. Ivo Krummenacher James D. Mattock Jonas H. Müssig Torsten Thiess Dr. Alfredo Vargas Dr. Jiji Zhang 《Angewandte Chemie (International ed. in English)》2017,56(27):8009-8013
The diborene 1 was synthesized by reduction of a mixture of 1,2-di-9-anthryl-1,2-dibromodiborane(4) ( 6 ) and trimethylphosphine with potassium graphite. The X-ray structure of 1 shows the two anthryl rings to be parallel and their π(C14) systems perpendicular to the diborene π(B=B) system. This twisted conformation allows for intercalation of the relatively high-lying π(B=B) orbital and the low-lying π* orbital of the anthryl moiety with no significant conjugation, resulting in a small HOMO–LUMO gap (HLG) and ultimately a C−H borylation of the anthryl unit. The HLG of 1 was estimated to be 1.57 eV from the onset of the long wavelength band in its UV/Vis absorption spectrum (THF, λonset=788 nm). The oxidation of 1 with elemental selenium afforded diboraselenirane 8 in quantitative yield. By oxidative abstraction of one phosphine ligand by another equivalent of elemental selenium, the B−B and C1−H bonds of 8 were cleaved to give the cyclic 1,9-diborylanthracene 9 . 相似文献