功能性有序微结构的制备及潜在应用

随着科技的发展进步,具有特殊功能的有序微结构日渐引起人们浓厚的研究兴趣,并被广泛应用于微电子器件、微反应器、生物化学传感器以及光学器件等领域.本文总结了我们课题组在微观表面图案化和有序微结构制备及应用方面的研究工作,重点介绍我们在该方向工作的最新进展,并对该领域的发展前景进行了展望.     

有序金属纳米壳材料

有序金属纳米壳结构特别是有序中空纳米壳及大孔结构兼具了光子晶体和金属纳米壳结构的光学特性,引起了国内外学者的广泛关注。本文详细介绍了有序金属纳米壳材料的制备方法与步骤,主要包括胶体晶模板的组装、所需金属壳层的制备以及胶体晶模板的去除三步,并对各步的制备方法及特点进行了描述。此外,本文还对金属纳米壳有序材料的各种应用进行了综述,简要分析了目前存在的问题并展望了今后该材料的研究方向。     

Improved efficiency of focal point conformational analysis with truncated correlation consistent basis sets

It has been suggested that the computational cost of correlated ab initio calculations could be reduced efficiently by using truncated basis sets on hydrogen atoms (Mintz et al., J Chem Phys 2004, 121, 5629). We now explore this proposal in the context of conformational analysis of small molecules, such as hydrogen peroxide, dimethyl ether, ethyl methyl ether, formic acid, methyl formate, and several small alcohols. It is found that truncated correlation consistent basis sets that lack certain higher angular momentum functions on hydrogen atoms offer accuracy similar to traditional Dunning's basis sets for conformational analysis. Combination of such basis sets with the basis set extrapolation technique to estimate Hartree-Fock and M?ller-Plesset second order energies provides composite extrapolation model chemistries that are significantly more accurate and faster than analogous single point calculations with traditional correlation consistent basis sets. Root mean square errors of best composite extrapolation model chemistries on the used set of molecules are within 0.03 kcal/mol of traditional focal point conformational energies. The applicability of composite extrapolation methods is illustrated by performing conformational analysis of tert-butanol and cyclohexanol. For comparison, conformational energies calculated with popular molecular mechanics force fields are also given.     

Functionalized Porphyrin Discotic Liquid Crystals: Photoinduced Charge Separation and Trapping

Individual members of a family of highly absorptive porphyrins bearing symmetrically positioned flexible side chains form discotic liquid crystalline mesophases at modest temperature ranges. The order of this phase is preserved when a thin layer of this self-assembled material is cooled to room temperature. Exposure of such films to visible excitation, with or without an externally applied electrical field, produces photovoltaic effects and/or charge trapping. The latter effect constitutes the basis for optoelectronic information storage.     

Medium-size polarized basis sets for high-level-correlated calculations of molecular electric properties

Summary The first-order polarized basis sets for the use in high-level-correlated investigations of molecular electric properties have been generated for Pb, Bi, Po, and At. The performance of the standard [10.17.14.5/13.11.8.2] and extended [20.17.14.9/13.11.8.4] basis sets has been examined in nonrelativistic and quasirelativistic calculations for atoms and simple closed-shell hydrides. The relativistic contributions to electric dipole properties of those systems have been evaluated by using the recently developed quasirelativistic scheme. The predicted dipole polarizability of At is in good agreement with the results of other relativistic calculations. The calculated quasirelativistic dipole moments of BiH₃ (–0.499 a.u.), PoH₂ (–0.207 a.u.), and AtH (+0.036 a.u.) involve a significant relativistic contribution which amounts to —0.230 a.u., –0.177 a.u., and –0.097 a.u., respectively. The basis set details append this paper. They are also available as a part of the basis set library of the MOLCAS system.     

Fabrication, Characterization and Electrocatalysis of an Ordered Carbon Nanotube Electrode

A method for fabrication of ordered carbon nanotube (CNT) film,which was template-synthesized within the highly ordered pores of a commercially available alumina template membrane,modified glassy carbon(CNT/GC) electrode was established.The CNT/GC electrode showed excellent electrocatalytic activity toward dopamine electrochemical reaction without introducing any electrochemically active group into CNT film or activating any electrochemically active group into CNT film or activating the electrode electrochemically.DA undergoes ideal reversible electrochemical reaction on CNT/GC electrode at low scan rate(≤20mV/s) with an excellent reproducibility and stability.The CNT/GC electrode might be used in biosensors because the highly ordered CNT may present a steric effect on more efficient redox reactions of biomolecules.     

Cyclocondensation of 2-Aminobenzimidazole with Dimedone and Its Arylidene Derivatives

The reactions of 2-aminobenzimidazole with substituted benzaldehydes and dimedone, 2-arylidene derivatives of dimedone, 9-arylhexahydro-1H-xanthene-1,8(2H)-diones and also with dimedone and DMF have been studied. The direction of formation of the pyrimidine ring has been established and discussed. An X-ray structural investigation of 2,2-dimethyl-2,3-dihydrobenzimidazo[1,2-a]quinazolin-4(1H)-one has been carried out.     

3DOM InVO4-supported chromia with good performance for the visible-light-driven photodegradation of rhodamine B

Three-dimensionally ordered macroporous (3DOM) monoclinic InVO₄ and its supported chromia (yCrO_x/3DOM InVO₄, y denotes as the weight percentage of Cr₂O₃, y = 5, 10, 15, and 20 wt%) photocatalysts were fabricated using the ascorbic acid-assisted polymethyl methacrylate-templating and incipient wetness impregnation methods, respectively. Physicochemical properties of the materials were characterized by means of a number of analytical techniques. Photocatalytic activities of the samples were evaluated for the degradation of rhodamine B (RhB) in the presence of H₂O₂ under visible-light illumination. Compared to 3DOM InVO₄ and 15CrO_x/bulk InVO₄, yCrO_x/3DOM InVO₄ showed much better visible-light-driven photocatalytic performance for RhB degradation, with the 15CrO_x/3DOM InVO₄ sample performing the best. It is concluded that the CrO_x loading, higher surface area and surface oxygen vacancy density and lower bandgap energy as well as the better quality of 3DOM structure were responsible for the good photocatalytic performance of 15CrO_x/3DOM InVO₄ for the degradation of RhB.     

以天然植物为模板合成高度有序的多级复合孔材料

筛选出两种孔径较大且孔结构规则的植物为大孔模板, 以嵌段共聚物为介孔相模板成功合成了两种具有连续的骨架和贯通的大孔孔道(大孔孔径大于40 μm, 其孔壁为介孔相)的高度有序多级复合孔材料. 对该复合孔材料进行了水热稳定性研究. 用扫描电子显微镜(SEM)、粉末X射线衍射仪(XRD)、高分辨率透射电镜(HRTEM)以及N₂吸附-脱附等测试手段对合成的样品进行了表征. 结果表明, 合成的产物是孔道相互贯通的多级有序复合孔硅材料, 具有较好的水热稳定性. 采用此合成方法可精确地复制大孔植物模板.