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451.
Seebacher W Kröpfl D Belaj F Saf R Hüfner A Weis R 《Molecules (Basel, Switzerland)》2005,10(3):521-533
Benzylidene acetone reacts with thiocyanates derived from secondary amines in a one-pot reaction to give 4-aminobicyclo[2.2.2]octan-2-ones. The reaction mixture was investigated for the presence of possible intermediates using GC-MS. These intermediates - diketones and enamines - were prepared and exposed to the same reaction conditions to examine the reaction mechanism. The reaction of ethyl styryl ketone with thiocyanates of secondary amines yielded cyclohexanone derivatives instead of the expected bicyclo- octanones. Their structures were established by means of a single crystal structure analysis. 相似文献
452.
Griessl SJ Lackinger M Jamitzky F Markert T Hietschold M Heckl WM 《Langmuir : the ACS journal of surfaces and colloids》2004,20(21):9403-9407
A two-dimensional molecular template structure of 1,3,5-benzenetricarboxylic acid (trimesic acid, TMA) was formed on a highly oriented pyrolytic graphite surface (HOPG) by self-assembly at the liquid-solid interface. Scanning tunneling microscopy (STM) investigations show high-resolution images of the porous structure on the surface. After the host structure was created, coronene molecules were inserted as guest molecules into the pores. STM results indicate that some of the guest molecules rotate inside their molecular bearing. Further investigations show that single coronene molecules can be directly kicked out of their pores by means of STM. 相似文献
453.
Anatolij Dvurečenskij Ferdinand Chovanec 《International Journal of Theoretical Physics》1988,27(9):1069-1082
Using ideas from fuzzy set theory, we generalize the notion of a quantum (probability) space introduced by Suppes to so-called fuzzy quantum spaces and we study the compatibility problem. 相似文献
454.
The differences in the electron-impact-induced fragmentation of ortho and para- nitrobenzoylpiperidine are connected with neighbouring group participation of the NO2 group. New oxygen migration, as well as the formation of stabilised radicals by intramolecular interaction of both functions, are only possible with the ortho compound. 相似文献
455.
Manfred Schubert-Zsilavecz Dagmar Gusterhuber Ferdinand Belaj 《Monatshefte für Chemie / Chemical Monthly》1990,121(6-7):555-564
Summary Addition of trimethylbenzonitril oxide to 2-hydroxyethylamino-1,4-quinones and 3,4-dihydro-4-alkyl-8a-methoxy-2H-1,4-benzoxazin-6(8aH)-ones leads to 7,8,9a,9b-tetrahydro-3aH-1,2-oxazolo[4,5-h]-1,4-benzoxazin-4(6H)-ones. In order to determine constitution and conformation of the addition products an NMR-spectroscopic analysis and an X-ray crystal structure analysis of 6-benzyl-9a-hydroxy-3-mesityl-7,8,9a,9b-tetrahydro-3aH-1,2-oxazolo[4,5-h]-31,4-benzoxazin-4-(6H)-one3a were carried out at room temperature: C25H26N2O4,M
r=418.49, monoclinic, P21/n,a=13.716(6),b=19.993(6),c=15.348(6) Å, = 98.55(4)°,V=4162(1)Å3,Z=8,d
x=1.336g/cm3,R=6.77%,R
w=4.55% (2994 observables, 560 parameters). 相似文献
456.
457.
The 26,23-lactone derivative of 1alpha,25-dihydroxyvitamin D3, TEI-9647, is a partial antagonist of the of human vitamin D receptor (VDR). However, we found that TEI-9647 in rat cells behaves as a weak VDR agonist. This behavior could be mimicked in human cells by the double mutagenesis of human VDR (specifically C403S and C410N). The increased agonistic action of TEI-9647 correlates to a gain in the interaction of the VDR with coactivator protein and a decreased stabilization of the antagonistic conformation of the receptor. Molecular dynamics simulations indicated that TEI-9647 acts as antagonist of human VDR by reducing the stability of helix 12 of the ligand binding domain. In contrast, N410 of the rat VDR stabilized, via backbone contacts, the interaction between helices 11 and 12. This results in TEI-9647 becoming a weak agonist in this organism. 相似文献
458.
Synthesis, Crystal Structure and Electronic Band Structure of the Isostructural Sulfide Chlorides CuBiSCl2 and AgBiSCl2 Black, platelet crystals of MBiSCl2 (M = Cu, Ag) were synthesized by heating stoichiometric amounts of MCl and BiSCl. X‐ray diffraction on powders and single‐crystals revealed that the compounds crystallize isostructural with space group Cmcm (Cu/Ag: a = 396.9(1)/397.1(1); b = 1278.6(3)/1371.2(3); c = 859.7(2)/882.4(2) pm). In the crystal structures the BiIII cations have a bi‐capped trigonal prismatic coordination of two sulfide and six chloride ions. The polyhedra constitute layers equation/tex2gif-stack-2.gif[BiS2/2Cl6/3—] by sharing common edges and faces. The layers are separated by transition metal cations MI. Their distorted octahedral coordination comprises two short bonds M—S in trans position and four M—Cl bonds that are about 50 pm longer. From relativistic band structure calculations (DFT) is deduced that AgBiSCl2 is an indirect semi‐conductor with a band gap of about 1.0 eV. 相似文献
459.
An experimental apparatus for the measurement of the EMF of galvanic cells with solid state electrolytes and with separate gas chambers around the electrolytes is described. This provides the possibility of a more precise determination of the thermodynamic values for solid alloys. Measurements on alloys from the copper-rich solid solution region of the CuSn system resulted in a linear temperature dependence of the measured EMF values with very little scatter. The partial free energies of mixing and the integral mixing enthalpies obtained using the published value of Petot-Ervas [10] for the formation enthalpy difference of the oxides NiO and SnO2 agree well with the literature data, which were determined by other methods. 相似文献
460.
A quantum chemical study of the electronic structure of negatively charged phenylenevinylene (PV) oligomers and methoxy-substituted derivatives is presented. The geometries of the PV oligomers were optimized using density functional theory. The geometry deformations are found to be delocalized along the entire oligomer chain without indication of polaron formation. The optical absorption spectra of the negatively charged PVs were calculated using both time-dependent density functional theory (TDDFT) and the singly excited configuration interaction method with an intermediate neglect of differential overlap reference wave function (INDO/s-CIS). The available experimental optical absorption energies are reproduced by the calculations. Introduction of methoxy substituents reduces the transition energies, while this does not have a strong effect on the charge distribution along the chain. DFT calculations yield a more delocalized excess negative charge than that of INDO/s-CIS calculations. 相似文献