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691.
    
We have successfully expanded the library of amino–NHCs with varying substituents on the amine group, leading to insight about the instability of NHCs arising from the intermolecular interaction of the dangling amine side‐arm. However, the pendant amine plays an important role with respect to the catalytic process, resuscitating the catalytic activity of unsaturated NHC’s through a synergistic effect invoked by the secondary amine. This proof of concept allows us to expand the spectrum of catalysis to C C, as well as C B bond formation.  相似文献   
692.
Summary The atomic-dipole squeezing condition for arbitrarily prepared atomic and field states in multi-photon Jaynes-Cummings model was derived. Three special cases were discussed. For the field initially in a vacuum state and a certain eigenstate of the Susskind-Glogower phase operator, the analytical dipole squeezing conditions were obtained and the maximum squeezing values were calculated. For a squeezed vacuum input field, the dipole squeezing behaviours under the influence of the field squeezing parameterr and the phased atom were numerically treated.  相似文献   
693.
The condensation of 1,2-bisalkoxy-4,5-diaminobenzene 2a-e derivatives with freshly prepared hexaketocyclohexane give hexakis(alkoxy)diquinoxalino[2,3-a:2′,3′-c]phenazines in good yield. DSC and polarization microscopy showed HATOC6 has both the crystalline (K) to mesophase (M) and the mesophase (M) to isotropic (I) phase transitions. Importantly, the alkoxy substituted compound synthesized showed an M-I transition because of greater stability, whereas the reported alkyl-thiol decomposes after the mesophase.  相似文献   
694.
The photoelectron spectra of eighteen compounds which are dienes or diene—iron tricarbonyl complexes have been investigated. A comparison of the photoelectron spectra of the dienes and corresponding iron carbonyl complexes has yielded the values of the perturbation energies for the two π orbitals of the diene moiety caused by interaction with Fe(CO)3. These perturbation energies are relatively constant (Δπ1 = 0.89 ± 0.07 eV, Δπ2 = 0.22 ± 0.06 eV) throughout the series. They have been employed to estimate the π ionization energies of the organic transient species cyclobutadiene (8.29 and 11.95 eV) and trimethylenemethane (8.36 and 11.79 eV), two novel molecules which have not been studied successfully by photoelectron spectroscopy to date.  相似文献   
695.
Summary It is shown that in projection microradiography it is advantageous to use a magnification 2. The gain in intensity and ease of operation is discussed.  相似文献   
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The direct synthesis of the two industrially important organotin intermediates, di(n-butyl)tin and di(n-octyl)tin dihalides, has been investigated by reacting the appropriate alkyl halide with metallic tin undervarying conditions. Observations were made on the influences of temperature, pressure, reaction time, nature of the tin metal, organic halide/tin reactant ratios and the presence of catalysts on the extent of tin conversion and yields of the organotin products. The efficacy of the onium halides, notably n-Bu4NI, Me3SI and Ph3MeAsI, either singly or in binary combinations with iodine or inorganic iodine compounds, in catalysing the synthesis of the above dialkyltins as well as higher di(n-alkyl)tin analogues is described.  相似文献   
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