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121.
Photolysis of complexes of the type M(2)(CO)(6)(RC(5)H(4))(2) (where M = W, Mo, Cr and R = H (Cp) or CH(3) (Cp')) leads to the production of short lived 17-electron radicals. Direct electrochemical characterization of these intermediates has been achieved using a technique known as photomodulated voltammetry (PMV). The results from PMV analysis are in excellent agreement with literature estimates for CpMo(CO)(3)(*) and CpCr(CO)(3)(*). However, CpW(CO)(3)(*) is found to be shifted oxidatively 115 mV relative to previous literature estimates. The change in the value for the tungsten complex changes previous estimates to the bond dissociation energy for tungsten metal hydrides by 3.0 +/- 0.9 kcal/mol. Lifetime information on the radicals is also reported based on the phase shift of the electrochemical signal observed by PMV under limiting current conditions. 相似文献
122.
The UV/visible spectra of a series of diazonium fast dyes have been evaluated by using a time-dependent density functional theory approach explicitly taking into account bulk solvation effects. Using the PBE0 functional with the 6-311G(2d,2p) atomic basis set, the agreement between theory and experiment is excellent for these cationic species. The effects on the spectra of chemical substitution are analysed. 相似文献
123.
124.
Thermally Activated Delayed Fluorescence in a Y3N@C80 Endohedral Fullerene: Time‐Resolved Luminescence and EPR Studies 下载免费PDF全文
Dr. Michal Zalibera Denis S. Krylov Dimitrios Karagiannis Paul‐Anton Will Frank Ziegs Sandra Schiemenz Prof. Dr. Wolfgang Lubitz Prof. Dr. Sebastian Reineke Dr. Anton Savitsky Dr. Alexey A. Popov 《Angewandte Chemie (International ed. in English)》2018,57(1):277-281
The endohedral fullerene Y3N@C80 exhibits luminescence with reasonable quantum yield and extraordinary long lifetime. By variable‐temperature steady‐state and time‐resolved luminescence spectroscopy, it is demonstrated that above 60 K the Y3N@C80 exhibits thermally activated delayed fluorescence with maximum emission at 120 K and a negligible prompt fluorescence. Below 60 K, a phosphorescence with a lifetime of 192±1 ms is observed. Spin distribution and dynamics in the triplet excited state is investigated with X‐ and W‐band EPR and ENDOR spectroscopies and DFT computations. Finally, electroluminescence of the Y3N@C80/PFO film is demonstrated opening the possibility for red‐emitting fullerene‐based organic light‐emitting diodes (OLEDs). 相似文献
125.
A Planar‐Chiral Rhodium(III) Catalyst with a Sterically Demanding Cyclopentadienyl Ligand and Its Application in the Enantioselective Synthesis of Dihydroisoquinolones 下载免费PDF全文
Dr. Evgeniya A. Trifonova Nikita M. Ankudinov Dr. Andrey A. Mikhaylov Dr. Denis A. Chusov Dr. Yulia V. Nelyubina Prof. Dr. Dmitry S. Perekalin 《Angewandte Chemie (International ed. in English)》2018,57(26):7714-7718
The rapid development of enantioselective C?H activation reactions has created a demand for new types of catalysts. Herein, we report the synthesis of a novel planar‐chiral rhodium catalyst [(C5H2tBu2CH2tBu)RhI2]2 in two steps from commercially available [(cod)RhCl]2 and tert‐butylacetylene. Pure enantiomers of the catalyst were obtained through separation of its diastereomeric adducts with natural (S)‐proline. The catalyst promoted enantioselective reactions of aryl hydroxamic acids with strained alkenes to give dihydroisoquinolones in high yields (up to 97 %) and with good stereoselectivity (up to 95 % ee). 相似文献
126.
127.
In the quantum rotor model with random exchange interactions having a nonzero mean, three phases, a (i) phase (Bose) glass, (ii) superfluid, and (iii) Mott insulator, meet at a bicritical point. We demonstrate that proximity to the bicritical point and the coupling between the energy landscape and the dissipative degrees of freedom of the phase glass lead to a metallic state at T = 0. Consequently, the phase glass is unique in that it represents a concrete example of a metallic state that is mediated by disorder, even in 2D. We propose that the experimentally observed metallic phase which intervenes between the insulator and the superconductor in a wide range of thin films is in actuality a phase glass. 相似文献
128.
Kraft P Bajgrowicz JA Denis C Fráter G 《Angewandte Chemie (International ed. in English)》2000,39(17):2963
The cover picture shows, on the lip of Oncidium tigrinum La Llave et Lex., the superposition of beta-ionone and a tailor-made bicyclo[6.4.0]dodecene. The structural similarity of the two molecules accounts for their close odors. beta-Ionone is present in the scent of the depicted tropical orchid at the unusually high level of 14.5 %. An overview of the olfactory spectrum is shown in the background. More on scents and their molecules can be found in the review of P. Kraft et al. on p. 2980 ff. 相似文献
129.
We briefly report on new results concerning a perturbation expansion structure within the framework of an analytic version of perturbative quantum chromodynamics (pQCD). This approach combines the RG symmetry with the Källén–Lehmann analyticity in the Q2 variable. The procedure of analytization matches this analyticity with the RG invariance by adding to the analytized invariant coupling
some nonperturbative contributions containing no adjustable parameters. In turn, the new perturbative expansion (the APT expansion) for an observable represents asymptotic expansion over a nonpower set of specific functions
rather than in powers of
. We analyze this set and show that it obeys different properties in various ranges of the Q2 variable. In the UV, it is close to the power set
used in the pQCD calculation. However, generally, this set is of a more complicated nature. In the low Q2 region the behavior of
is oscillating. Here, the APT expansion has a feature of asymptotic expansion à la Erdélyi. The issue of the consistency of an analytization procedure with the RG structure of observables is also discussed. 相似文献
130.
Title compounds have been prepared from carbonyl compounds by formal removal of hydroxyl and sulfenyl or hydroxyl and selenyl moieties from the corresponding functionalized β-hydroxysulfides or β-hydroxyselenides. 相似文献