We report a facile diversity oriented synthesis of α- and β-amino acids, by utilizing the pluripotent α-methylene group in a chiral bicyclic lactam as our key point of transformation. 相似文献
We report for the first time the preparation of single polypyrrole (PPy) molecule chains using a “metal‐organic framework” with 1 nm channels as a template. The obtained one‐dimensional (1‐D) PPy has highly structure order and excellent conductivity, which has improved by as much as five orders of magnitude in comparison with that of 2‐D PPy.
A new series of 4′-substituted-7-(4″-decyloxybenzoyloxy)-4H-1-benzopyran-4-one esters have been synthesized and their mesomorphic properties have been studied along with the spectroscopic and optical-oriented technique in which the smectic layer spacing of compound with fluorine substituent has been well substantiated by X-ray diffraction. Phase transition temperatures and the respective enthalpy values of the title compounds are obtained from differential scanning calorimetry, whilst texture observation is performed under polarizing optical microscopy. The thermal data indicate that all title compounds are thermotropic exhibiting either monomorphism or variants of polymorphism. Crystal paramorphism is also observed for some of the title compounds. The variation in transition temperatures as a consequence of structural changes of the title compounds is discussed. 相似文献
Potentialities of new combined deformation schemes, including the solid-state extrusion through conical die (ED) and equal-channel multiple angle extrusion (ECMAE) implemented in different sequences to modify the structure and properties of semicrystalline polymers, have been studied for polyamide-6 (PA-6) as an example. It is shown that deformation by the ED–ECMAE scheme gives the best complex of physical and mechanical properties. A significal improvement of elastic and strength properties of PA-6 with a conserved high level of plastic characteristics has been observed. 相似文献
The angular intensity distribution of thermal energy He beam scattered from highly oriented pyrolytic graphite (HOPG) surface has been measured by means of supersonic molecular beam scattering technique in the wide surface temperature range. To separate the elastic and inelastic scattering components, simple analysis method has been developed by applying the classical binary collision theory of the hard cube model (HCM). From the extracted elastic scattering component in the scattering distribution, the Debye temperature of the HOPG surface has been derived as 590 ± 30 K. On the basis of the HCM analysis for the extracted inelastic scattering components of He beam, the effective mass for the HOPG surface has been found to be 72 u (six carbon atoms). 相似文献
Macrolines constitute a class of natural products that has more than 100 members and displays diverse biological activities. These compounds feature a cycloocta[b]indole scaffold that represents an interesting target structure for biology‐oriented synthesis (BIOS). We have presented a solid‐phase synthesis of isomerically pure cycloocta[b]indoles by employing the Pictet–Spengler reaction and the Dieckmann cyclization as key steps. The scope of this reaction sequence was investigated in more detail by using various additional diversification procedures, such as Pd‐catalyzed Sonogashira or Suzuki couplings on a solid phase, thus allowing, for example, the generation of 10‐substituted cycloocta[b]indole derivatives. Finally, solution‐phase decoration of the cycloocta[b]indole skeleton by reduction and saponification was evaluated, thereby further extending the scope of the solid‐phase synthesis. 相似文献
The oriented attachment (OA) mechanism has been investigated as an important process in the formation of anisotropic nanostructures such as depicted. The results showed that the control of a desired phase in this system may be attained by the control of OA mechanism through pH value, obtaining several morphologies.