New radical cation salts based on 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH-TTP), viz., κ-(BDH-TTP)4CuCl4·(H2O)n (1) and κ-(BDH-TTP)2[CuCl4]0.67· ·(H2O)0.33 (2), were synthesized and structurally characterized. Single crystals were prepared by the electrochemical oxidation of BDH-TTP
under galvanostatic conditions. The X-ray diffraction study showed that the salts have layered structures characterized by
the presence of κ-type BDH-TTP conducting layers. These layers alternate with the complex anions composed of [CuCl4]2− units and water molecules. Both salts exhibit the temperature dependence of the metallic conductivity down to 4.2 K. Spin-spin
antiferromagnetic correlations in the Cu2+ subsystem were observed in the crystals of 2. 相似文献
Stepwise application of the Pd-catalyzed S(N)2' reaction and the desilylative S(E)2' reaction to the ambivalent 2-bromo-1-silyl-1,3-dienes provides a novel route to the highly enantioselective construction of tertiary and quaternary propargylic stereogenic centers via axially chiral allenylsilanes. 相似文献
We investigated the effects of indium doping on the superconducting properties of YBCO sintered samples and thin films. In2O3-doped YBCO and YBa2Cu3−xInxOy sintered samples showed a gradual decrease in the critical temperature (Tc) with increasing indium content; however, a Tc value above 80 K was maintained even up to 30 vol.% addition and x = 0.4, respectively. Ba3Cu3In4O12 was detected by X-ray diffractometry and energy-dispersive X-ray spectroscopy as a reaction product for both sintered samples. The normalized Jc under a magnetic field of 0.1 T showed a maximum at x = 0.3. Indium-doped YBCO films prepared by pulsed laser deposition showed a similar dependence of Tc on indium content as the sintered samples. 相似文献
We have investigated current transport property in Gd1Ba2Cu3O7−δ coated conductor with artificial pinning centers in a wide range of temperature, magnetic field, B up to 27 T, and field angle. Due to the additional c-axis correlated pins, critical current density, Jc in B//c was enhanced and the improvement was observed in wide range of B. On the other hand, around B⊥c below 65 K, the angular dependence of n-value showed a valley-like behavior, although the Jc was increasing. In addition, the temperature dependence of the pinning force density defined as Jc × B was not scaled on an expected master curve. These results indicate the pinning in B⊥c is governed by different mechanism below 65 K and high magnetic field. 相似文献
Magnetic field effects (MFEs) on a photoinduced electron-transfer reaction in a semi-rigid linked system (RuP–C60) were examined in toluene and o-dichlorobenzene. The transient absorption spectra indicated that the photogenerated biradical produced by an intramolecular
electron-transfer reaction was observed only in o-dichlorobenzene. The decay rate constants (kd) for the biradical decreased steeply at lower magnetic fields (≤0.06 T) and rapidly recovered at 0.08 T. The kd value was observed to decrease gradually above 0.2 T. The MFEs strongly indicated the formation of the singlet-born biradical
for RuP–C60. The dip in the MFE at 0.06 T was ascribed to the S–T level crossing mechanism. The MFEs above 0.2 T can be explained by
a spin–spin relaxation mechanism due to the anisotropic Zeeman interaction being related to the exchange interaction. 相似文献
A combination of X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) using synchrotron radiation is applied to clarify surface chemical states of β-FeSi2 films fabricated by an ion-beam sputtering deposition method. The differences in the chemical states of the films fabricated at substrate temperatures of 873, 973 and 1173 K are investigated. For the film fabricated at 873 K, Si 2p XPS spectra indicate the formation of a relatively thicker SiO2 layer. In addition, Fe L-edge XAS spectra exhibit the formation of FeSi2−X by preferential oxidation of Si or the presence of unreacted Fe. The results for the film fabricated at 1173 K imply the existence of FeSi2 with α and ? phases. In contrast, the results for the film fabricated at 973 K indicate the formation of relatively homogeneous β-FeSi2. These imply that the relatively excellent crystal property of the film fabricated at 973 K is due to the formation of homogeneous β-FeSi2. As a conclusion, the combination of XPS and XAS using synchrotron radiation is a powerful tool to elucidate the surface chemical states of thin films. 相似文献
You oughta use water : Broad functional‐group (FG) tolerance was observed for the title coupling of aryl halides (X=Cl, Br, I) and aryl boronic acids to give biaryl compounds with up to 94 % ee. The chiral imidazoindole phosphine–palladium catalyst supported on an amphiphilic polystyrene–poly(ethylene glycol) (PS–PEG) resin could be recycled readily.