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Chen Y Su W Bai M Jiang J Li X Liu Y Wang L Wang S 《Journal of the American Chemical Society》2005,127(45):15700-15701
LB films of three amphiphilic tris(phthalocyaninato) rare earth triple-decker complexes with crown-ethers as hydrophilic heads and long alkyl chains as hydrophobic tails have been prepared and found to display very well ordered layer structures, as proved by pi-A isotherms, UV-vis and polarized absorption spectra, X-ray diffraction experiments, and microscopic morphology characterization. These LB films have been fabricated into field-effect transistor (FET) devices, which show carrier mobilities as high as 0.24-0.60 cm2 V-1 s-1, among the highest mobilities achieved thus far for all LB film-based OFETs. 相似文献
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The influence of introducing water molecules into a cation-pi complex on the interaction between the cation and the pi system was investigated using the MP2/6-311++G method to explore how a cation-pi complex changes in terms of both its geometry and its binding strength during the hydration. The calculation on the methylammonium-benzene complex showed that the cation-pi interaction is weakened by introducing H(2)O molecules into the system. For example, the optimized interaction distance between the cation and the benzene becomes longer and longer, the transferred charge between them becomes less and less, and the cation-pi binding strength becomes weaker and weaker as the water molecule is introduced one by one. Furthermore, the introduction of the third water molecule leads to a dramatic change in both the complex geometry and the binding energy, resulting in the destruction of the cation-pi interaction. The decomposition on the binding energy shows that the influence is mostly brought out through the electrostatic and induction interactions. This study also demonstrated that the basis set superposition error, thermal energy, and zero-point vibrational energy are significant and needed to be corrected for accurately predicting the binding strength in a hydrated cation-pi complex at the MP2/6-311++G level. Therefore, the results are helpful to better understand the role of water molecules in some biological processes involving cation-pi interactions. 相似文献
179.
γ—Mo2N合成过程中的热变化及中间产物的研究 总被引:2,自引:0,他引:2
采用DTA技术,通过改变升温速率研究了γ-Mo2N合成过程中的热变化,并经XRD,BET及IR测试,对DTA曲线中的谱峰进行归属,考察了中间产物,DTA结果表明,在MoO3和NH3程序升温反应过程中有放热峰及吸热峰出现,且随升温速率的长高,放热峰面积与吸热峰面积之比逐渐减小,结合XRD及IR结果可知,DTA曲线听放热峰可归属为由MoO3变化为MoO2的还原峰,吸热峰则归属为由MoO2变化为Mo2N 相似文献
180.
Michael A. Brook Jianxiong Jiang Philippa Heritage Brian Underdown Mark R. McDermott 《Colloids and surfaces. B, Biointerfaces》1997,9(6):391-295
Silicone-coated starch/protein (human serum albumin, HSA) microparticles were prepared by precipitation of a starch/HSA/DMSO/water (water-in-oil) emulsion into acetone containing a silicone: the silicone polymer was either unfunctionalized (SiMe3 terminated, PDMS) or functionalized at its termini with Si(OEt)3 groups (TES-PDMS). The microparticles of approximate diameter 2–7 μm were highly hydrophobic with advancing contact angles 115°. Over several minutes, however, the contact angle decreased to ca. 40–70°. Soxhlet extraction with water led to degradation of the microparticles, irrespective of the nature of their silicone coating, as evidenced by release of the protein from them. Intraperitoneal (IP) or gastric administration of the two different particles to mice, however, showed a clear difference between the two silicones. The microparticles coated with either PDMS or TES-PDMS led to very different immune responses. Oral administration of the microparticles prepared with functionalized silicone elicited a significant production of antibodies, whereas the particles prepared with the unfunctionalized silicone (PDMS) were only weakly active. By contrast, the IP results demonstrated that particles coated with PDMS elicited an immune response that was established much more rapidly than with the particles modified with TES-PDMS. It is proposed that the TES-PDMS forms a physically adhering film or covalent bond to the protein molecules, which serves to protect the microparticle from biological degradation in the gut and/or facilitates the microparticle/protein interaction with the immune system. 相似文献