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101.
Berthold Fischer Helmut W. Schmalle Markus R. Baumgartner Max Viscontini 《Helvetica chimica acta》1997,80(1):103-110
The first crystal structure of a molybdenum complex 9 with a hydrogenated pterin and a sulfur ligand contributes to the discussion about the active center of molybdenum and tungsten enzymes containing a molybdopterin cofactor. Complex 9 was synthesized through a redox reaction of [MoVIO2 (LN-S2)] ( 8 ; LN-S2 = pyridine-2, 6-bis(methanethiolato)) with 5, 6, 7, 8-tetrahydropterin ( 7 ). 2 HCl (H4Ptr.2 HCl). The complex crystallizes, with a non-coordinating Cl-atom acting as a counterion, in the monoclinic space group C2/c (No. 15) with cell dimensions a = 22.900(5), b = 10.716(2), c = 17.551(4) Å, β = 120.36(3)°, and Z = 8. We interpret 9 as [MoIVO(LN-S2)(H+-q-H2Ptr)]Cl (q = quinonoid; H2Ptr = dihydropterin), i.e., a MoIV monooxo center coordinated by a pyridine-2, 6-bis(methanethiolato) ligand and a protonated dihydropterin. The spectroscopic properties of this new complex are comparable to those of other crystalline molybdenum complexes of hydrogenated pterins without additional S-coordination. The slightly H2O-soluble complex 9 reacts with the natural enzyme substrate DMSO very slowly, possibly due to the lack of easily dissociable ligands at the metal center. 相似文献
102.
Breakstone A Crawley HB Dallavalle GM Doroba K Drijard D Fabbri F Firestone A Fischer HG Frehse F Geist W Giacomelli G Gokieli R Gorbics M Hanke P Heiden M Herr W Kluge EE Lamsa JW Lohse T Meyer WT Mornacchi G Nakada T Panter M Putzer A Rauschnabel K Rimondi F Siroli GP Sosnowski R Szczekowski M Ullaland O Wegener D 《Physical review letters》1985,55(20):2180-2183
103.
We prove the surjectivity of the symbol map of the Frechet algebra obtained by completing an algebra of convolution and multiplication operators in the topology generated by all L2-Sobolev norms. The proof is based on an n of Egorov's theorem valid for non-homogeneous principal symbols, discussed in [5], [6]. We use the hyperbolic equation u/t=i|D|u, 0<<1, which has its characteristic flow constant at infinity, so that no differentiability of the symbol is required there. 相似文献
104.
105.
By using an energy dispersive solid state detector, harmonics were separated in a Lauetype diffraction experiment with a single crystal and white primary radiation (Bremsstrahlung) from a conventional x-ray tube. Intensity changes around the absorption edge of an atom species in the crystal could be verified according to theory.Dedicated to Prof. Dr. H.E. Müser on the occasion of his 60th birthday 相似文献
106.
K. H. Fischer 《Zeitschrift für Physik B Condensed Matter》1985,60(2-4):151-159
The dynamics of vector spin glasses with additional random anisotropy is investigated in the mean field approximation. We find a cross-over of the upper critical line from a behaviour of Heisenberg spins with a field-temperature dependence
, for large fieldsH, to Ising like behaviourT
f
–TT
2/3
, for small fields and fixed anisotropy, in agreement with results of Kotliar and Sompolinsky. Here,
andT
f
are characteristic spin glass temperatures. In addition, one has a second line with reversed behaviour which presumably represents a cross-over line from weak to strong non-ergodicity. The local transverse susceptibility
T
() varies for large fields and 0 along the upper critical line as
vT
, with a critical exponentV
T
= 1/2 – 11D/60 J, whereD andJ are the anisotropy and exchange coupling constants, respectively. On the Ising-like part of the upper critical line one has isotropic spin glass parameters,q
L
=q
T
, and susceptibilities, and a critical exponent,
which is similar to that of Ising spins along the de Almeida-Thouless line.Dedicated to B. Mühlschlegel on the occasion of his 60th birthdaySFB Aachen-Jülich-Köln 相似文献
107.
108.
Solutions of CoII salts of organic acids in primary amines absorb molecular oxygen rapidly and irreversibly forming μ-dioxygen—cobalt complexes. Thermolysis leads to a homopolar cleavage of the OO bond with subsequent radical reactions involving ligand amine. After thermolysis the capacity of oxygen uptake is reestablished (catalysis). 相似文献
109.
Alfred Baszczyk Matthias Fischer Carsten vonHnisch Marcel Mayor 《Helvetica chimica acta》2006,89(9):1986-2005
The synthesis, characterization, and optical properties of a series of new 2,6‐disubstituted naphthalene‐bisimide dyes as molecular rods comprising terminal AcS groups is reported. The first series of dyes ( 1 – 3 ), comprising phenylhetero (Ph‐X) core substituents, cover a broad range of the VIS spectrum, ranging from yellow ( 2 ) over red ( 3 ) to blue ( 1 ). The second series of dyes contains benzylhetero (Bn‐X) core substituents ( 4 – 7 ). For the same heteroatom connecting the substituent to the naphthalene core, both series were found to display comparable colors. For the second series, the colors were blue ( 4 ), red ( 5 ), and violet ( 6, 7 ). The Ph‐X‐substituted dyes 1 – 3 are nonfluorescent, in contrast to the Bn‐X‐substituted compounds 4 – 7 . This rich variety of optical features that can be adjusted by rather small alterations of the core substituents makes these structurally very comparable molecular rods ideal candidates for optically triggered molecular‐transport investigations. Also, thanks to the terminal AcS groups, these compounds can be placed between nobel‐metal electrodes for optically triggered transport experiments. 相似文献
110.
Karlheinz Ballschmiter Rainer Bacher Angela Mennel Regina Fischer Ulrich Riehle Max Swerev 《Journal of separation science》1992,15(4):260-270
High resolution gas chromatography, with mass selective detection, has been used for the analysis of PCB on methyl 50 % octyl polysiloxane (SB 50 Octyl), methyl octadecyl polysiloxane, and a smectic polysiloxane (SB Smectic); and for the analysis of polychlorodibenzodioxins and polychlorodibenzofurans with 1 to 8 chlorine substituents on 100 % cyanopropyl siloxane (SP 2331), smectic polysiloxane (SB Smectic), a new polar stationary phase (DB-Dioxin). The analysis has also been performed by column coupling. 相似文献