新型四硫代富瓦烯衍生物的合成及其性质的研究

合成了3个新的含有卤素取代基的四硫代富瓦烯衍生物及6个新的相关化合物。利用溶液的电子吸收光谱对四硫代富瓦烯衍生物的性质进行了研究。研究结果表明, 四硫代富瓦烯衍生物的分子中π轨道之间的能级差较小, 因而分子具有较高的稳定性。     

Polymerization-induced viscoelastic phase separation in polyethersulfone-modified epoxy systems

The polymerization-induced phase-separation process of polyethersulfone (PES)-modified epoxy systems was monitored in situ continuously on a single sample throughout the entire curing process by using optical microscopes, time-resolved light scattering (TRLS), scanning electronic microscopes (SEM), and a rheometry instrument. At specific PES content a viscoelastic transformation process of phase inversion morphology to bicontinuous was found with an optical microscope. The rheological behavior during phase separation corresponds well with the morphology development. Light-scattering results monitoring the phase-separation process of systems with final phase inversion morphology show a typical exponential decay procedure of scattering vector qm. The characteristic relaxation time of phase separation can be described well by the WLF equation.     

Multiresolution quantum chemistry in multiwavelet bases: Hartree-Fock exchange

In a previous study we reported an efficient, accurate multiresolution solver for the Kohn-Sham self-consisitent field (KS-SCF) method for general polyatomic molecules. This study presents an efficient numerical algorithm to evalute Hartree-Fock (HF) exchange in the multiresolution SCF method to solve the HF equations. The algorithm employs fast integral convolution with the Poission kernel in the nonstandard form, screening the sparse multiwavelet representation to compute results of the integral operator only where required by the nonlocal exchange operator. Localized molecular obitals are used to attain near linear scaling. Results for atoms and molecules demonstrate reliable precision and speed. Calculations for small water clusters demonstrate a total cost to compute the HF exchange potential for all n(occ) occpuied MOs scaling as O(n(occ) (1.5)).     

Boomerang‐Type Substitution Reaction: Reactivity of Fullerene Epoxides and a Halofullerenol

The C_s‐symmetric fullerene chlorohydrin C₆₀(Cl)(OH)(OOtBu)₄ reacts with 4‐dimethylaminopyridine (DMAP) and 1,4‐diazabicyclo[2.2.2]octane (DABCO) to yield two isomers with the formula C₆₀(O)(OOtBu)₄ in good yields. These isomers differ with respect to the location of the epoxy functionality. The one from DMAP is C_s symmetric, whereas that from DABCO is C₁ symmetric with the epoxy group on the central pentagon. Two different mechanisms are proposed to explain the chemoselectivity of these reactions. The reaction with DMAP involves single‐electron transfer as the key step; DMAP acts as the electron donor. A combination of an oxygen‐atom shift and S_N2′′ processes (boomerang substitution) are responsible for the formation of isomer with DACBO. Various related reactions support the proposed mechanisms. The structures of new fullerene derivatives were determined by spectroscopy, single‐crystal X‐ray analysis, and chemical correlation experiments.     

Distribution of components in the rare earth ammonia synthesis catalysts and effect of additives

The distribution of components in the HG-1 ammonia catalyst promoted by rare earth oxide (successfully developed by the authors) was analyzed by electron microprobe photography. The results enable us to explain the effect of additives upon the activity as well as the remarkably high lifetime of catalyst.

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金属基底上吡咯光电化学聚合的研究

近年来,国内外对聚吡咯已进行广泛的研究,主要内容包括:电化学聚合,机理与结构表征,电化学氧化还原性质,聚吡咯的化学修饰。最近报导了半导体上吡咯的光电化学聚合。我们在低于吡咯电聚合电位下观察到聚吡咯的Raman讯号。本文研究在中性溶液中金属基底上吡咯的光电化学聚合,以及光源波长、强度和介质等因素的影响。     

Styrene polymerization in ternary microemulsions: effects of water-soluble and oil-soluble initiators

The polymerization of styrene in ternary microemulsions stabilized by the cationic surfactant tetradecyltrimethylammonium bromide was studied as a function of concentrations of water-soluble (potassium persulfate, KPS) and oil-soluble (AIBN) initiators. At a particular molar ratio of the initiators, similar maximum rates of polymerization can be achieved from using both types of the initiators. In addition, both initiated systems produced microlatexes with similar hydrodynamic radius, number of polymer particles, molecular weight of polystyrene and number of polymer chain per latex particle. But the dependencies of these latex parameters on concentrations of KPS and AIBN may not be the same. The polymerization mechanism appears to be similar, irrespective of using KPS or AIBN. It is discussed in terms of effective radicals produced for the polymerization. While the different dependencies of some latex parameters on concentrations of the initiators are attributed to the different efficiencies of the initiators in producing effective radicals.     

电化学聚对苯膜的现场ESR及其性能研究

本文用现场电化学-ESR联合测试的技术, 对电化学聚对萃膜在浓H_2SO_4中的性质进行了研究, 结果表明: 聚对苯膜具有高的电导率和相对低的自旋磁化率, 极化子与偶极化子为主要导电者, 并在一定的电位下相互转化, 自旋粒子有很大的离域性。膜中链与链之间可能存在部分的氧桥结构, 而引起体系结构的某些变化, 使聚对苯膜的电导提高以及掺杂容易进行。掺杂量受电位控制, 浓H_2SO_4中的HSO_4~-嵌入/脱嵌的电化学可逆性很好, 最大掺杂量可相当于每5个苯环单元氧化出一个正电荷, 可望将电化学聚对苯用作稳定的二次电池电极材料。     

Synthesis of oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) triads as antenna molecules for energy transfer

The oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) (P-OPVn, n=2, 4, where n is the number of phenyl rings) and the complex with Zn²⁺ based on P-OPVn were synthesized for investigating their photophysical properties via UV-vis, voltammetry, steady-state and time-resolved fluorescence spectra. In these molecules two OPV moieties as energy donors were linked to porphyrin center by virtue of Wittig reaction. The detailed studies of photophysical properties indicate that OPV group can act as an antenna unit for effective intramolecular energy transfer.     

邻氨基酚电聚合膜的研究

在酸性溶液中, 邻氨基酚(OAP)可电聚合成均匀的活性聚邻氮基酚膜(POAP), 膜有致密结构和“张开”结构。POAP膜的主要结构形式为: 与Ni~(2+)络合后, 形成POAP—Ni~(2+)膜, 其主要结构形式为: