In this work, we present fluorescence yield and width values of Ne-, Ar-, and Kr-like ion levels for selected values of Z, using a state-of-the-art multiconfiguration Dirac–Fock approach. The results may be useful for the interpretation of spectra from plasmas, in both laboratory and astrophysics, as well as from ion collision experiments. 相似文献
BODIPY laser dyes constitute a fascinating topic of research in modern photochemistry due to the large variety of options its chromophore offers, which is ready available for a multitude of synthetic routes. Indeed, in the literature one can find a huge battery of compounds based on the indacene core. The possibility of modulating the spectroscopic properties or inducing new photophysical processes by the substitution pattern of the BODIPY dyes has boosted the number of scientific and technological applications for these fluorophores. Along the following lines, I will overview the main results achieved in our laboratory with BODIPYs oriented to optoelectronic as well to biophotonic applications, stressing the more relevant photophysical issues to be considered in the design of a tailor‐made BODIPY for a certain application and pointing out some of the remaining challenges.
The bis(silyl)triazene compound 2,6‐(Me3Si)2‐4‐Me‐1‐(N?N? NC4H8)C6H2 ( 4 ) was synthesized by double lithiation/silylation of 2,6‐Br2‐4‐Me‐1‐(N?N? NC4H8)C6H2 ( 1 ). Furthermore, 2,6‐bis[3,5‐(CF3)2‐C6H3]‐4‐Me‐C6H2‐1‐(N?N? NC4H8)C6H2 derivative 6 can be easily synthesized by a C,C‐bond formation reaction of 1 with the corresponding aryl‐Grignard reagent, i.e., 3,5‐bis[(trifluoromethyl)phenyl]magnesium bromide. Reactions of compound 4 with KI and 6 with I2 afforded in good yields novel phenyl derivatives, 2,6‐(Me3Si)2‐4‐MeC6H2? I and 2,6‐bis[3,5‐(CF3)2? C6H3]‐4‐MeC6H2? I ( 5 and 7 , resp.). On the other hand, the analogous m‐terphenyl 1,3‐diphenylbenzene compound 2,6‐bis[3,5‐(CF3)2? C6H3]C6H3? I ( 8 ) could be obtained in moderate yield from the reaction of (2,6‐dichlorophenyl)lithium and 2 equiv. of aryl‐Grignard reagent, followed by the reaction with I2. Different attempts to introduce the tBu (Me3C) or neophyl (PhC(Me)2CH2) substituents in the central ring were unsuccessful. All the compounds were fully characterized by elemental analysis, melting point, IR and NMR spectroscopy. The structure of compound 6 was corroborated by single‐crystal X‐ray diffraction measurements. 相似文献
The compound 1,c‐3‐diphenyltetran‐r‐1‐ol (systematic name: 1,c‐3‐diphenyl‐1,2,3,4‐tetrahydro‐r‐1‐naphthol), C22H20O, which possesses the tetrahydronaphthalene core that is found in a large number of natural products, crystallizes with Z′ = 4 and with the four molecules forming a hydrogen‐bonded cyclic aggregate. The aliphatic six‐membered rings are present with two different conformations in the molecules of the asymmetric unit. A comparison with similar fragments reveals their conformational flexibility. In addition, the structure demonstrates the relative stereochemistries of the chiral centers, which are important since the title compound is used in the stereoselective synthesis of compounds with therapeutic activity. 相似文献
The natural coumarin, benahorin 1 has been synthesised in five steps from xanthotoxol 4. Marmelide has been shown to be the 3,3-dimethylallyl ether of xanthotoxol (imperatorin 9) and not as believed the 1,1-dimethylallyl ether 7. 相似文献
The equations of state of liquid methane at 125.00 K and of six liquid mixtures of carbon monoxide and methane at 116.30, 120.00 and 125.00 K have been measured from just above the saturation vapour pressure to the freezing pressure of methane. The results show that the excess volume VE is large and negative at low pressures but becomes less negative as the pressure is increased, being almost zero at the highest pressures. The curve of VE against the mole fraction x is very asymmetrical at low pressures, but becomes more symmetrical with rising pressure.The effect of pressure on the excess functions GE, HE and T·SE has been calculated. HE and T·SE prove to be much more sensitive to pressure than GE.Conformal solution theory, in the van der Waals one-fluid form, reproduces the experimental results very successfully. 相似文献
A suggestion on how black holes may appear in Das-Jevicki collective field theory is given. We study the behaviour of a “test” particle when energy is sent into the system. A perturbation moving near the potential barrier can create a large-distance black hole geometry where the seeming curvature singularity is at the position of the barrier. In the simplest “static” case the exact D=2 black hole metric emerges. 相似文献