Chiral separation of 1,1'-bi-2-naphthol and its analogue on molecular imprinting monolithic columns by HPLC

Two molecular imprinting polymer (MIP) monolithic columns with (S)-(-)-1,1'-bi-2-naphthol and (R)-(+)-5,5',6,6',7,7',8,8'-octahydro-1,1'-bi-2-naphthol as the templating molecules, respectively, have been prepared by in situ polymerization using 4-vinylpyridine and ethylene dimethacrylate as functional monomer and cross-linker, respectively. The columns with good flow-through properties were obtained by changing the molar ratio of the functional monomer and the template molecule. The effects of mobile-phase composition on separation of enantiomers were systematically investigated. The results indicate that hydrophobic interaction in aqueous solution and hydrogen-bonding interaction in ACN between the enantiomers and polymers could play important roles in the retention and resolution. The effects of chromatographic conditions, such as flow rate, column temperature, sample loading, on the enantioseparation were also studied. Further, these two MIP columns show a cross-reactivity.     

Ab initio through‐space/bond interaction analysis of the long C–C bonds in Bi(anthracene‐9,10‐dimethylene) photoisomers

The bi(anthracene‐9,10‐dimethylene) photoisomer has remarkably long C–C single bonds. To examine the lengthening of the C–C bond, we propose a novel procedure for quantitatively analyzing orbital interactions in a molecule at the level of the ab initio molecular orbital method. In this procedure, we can cut off the specific through‐space/bond interactions in a molecule by artificially increasing the absolute magnitude of the exponents in a Gaussian function. Then, the spatial orbital interactions were perfectly cut off, and, each term that makes up the total energy, that is, the nuclear–electron attractions, the electron–electron repulsions, and the nuclear–nuclear repulsions cancel each other. Several model molecules of the photoisomer were analyzed by this procedure. It was found that the orbital interaction between the p orbital on the benzene ring and the σ* orbital on the C–C bond in question, σ→σ* electron transfer through π orbital, weakens the C–C bond efficiently when these orbitals were located in the “periplanar” conformation. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

一种二帽pseudo-Keggin结构簇合物[HN(C_2H_5)_3]_3[N(C_2H_5)_3]_2[Mo_8~ⅣMo_4~ⅤV_2~ⅣO_(38)(PO_4)]的水热合成、结构和性质研究

金属－氧簇合物因其结构多样性及在催化、材料和医药等方面的应用而引起人们的关注犤１犦。在众多金属－氧簇合物中，Keggin结构及金属取代Keggin结构金属－氧簇被大量报道，但由于很难获得高质量单晶，有关二帽Keggin结构的报道非常少，目前只有几例报道犤２～９犦。近年来，随着水热法应用到金属－氧簇的合成，陆续获得了一系列具有新颖结构的簇合物。１９９８年，通过水热法获得了第一个二帽pseudo－Keggin结构簇合物犤NH４犦４H犤PMo８VⅣ４VⅤ２O４２犦·２４H２O犤１０犦。我们用水热法以三乙胺做模板剂获得了一种全新的二帽pse…     

Structural effects in electron transfer reactions: comparative interfacial electrochemical kinetics for cis- versus trans-dioxorhenium(V)(bi)pyridine oxidation

The comparative interfacial oxidation kinetics of the approximate structural isomers trans-(O)₂Re^V(py)⁺₄ and cis-(O)₂Re^V(bpy)(py)⁺₂ (py, pyridine; bpy, 2,2′-bipyridine) have been assessed in aqueous solution via conventional cyclic voltammetry at a highly ordered pyrolytic graphite (HOPG) electrode. HOPG was employed because of its known propensity to diminish interfacial electron transfer (ET) rates (by ca. three to four orders of magnitude) and because of a probable lack of importance of kinetic work terms (diffuse double-layer corrections). Measured rates for the trans complex exceed those for the cis by about a factor of 3. Expressed as an effective activation Gibbs energy difference ΔG^*, this corresponds to a cis-trans difference of ca. 3 kJ mol⁻¹. The actual vibrational barriers to ET have determined from a combination of published X-ray structural results (trans complex) and new resonance Raman results (cis complex). The values are 0.6 kJ mol ⁻¹ for the trans oxidation and 4.4 kJ mol⁻¹ for the cis oxidation (i.e. close to the barrier difference inferred from rate measurements). Further analysis shows that most of the barrier difference is associated with displacement of a (predominantly) Re-N(bpy) stretching mode found only in the cis system. Differences in metal-oxo displacements (cis > trans) are also implicated.     

2-芳基吲哚的敏化光氧化偶合反应

本文研究了十七种2-芳基吲哚(1a-1q)在甲醇-乙酸介质中的亚甲基蓝(MB)敏化光氧化反应, 发现有十五种吲哚(1a-1o)以85%-95%的产率给出2,2'-二芳基-[2,3'-联-1H-吲哚]-3(2H)-酮(2a-2o), 而2-(4-硝基苯基]吲哚(1p)和2-联苯基吲哚(1q)则分别生成2-甲氧基-2-(4-硝基苯基)-1,2-二氢-3H-吲哚-3-酮(7p)和2-联苯基-4H-3,1-苯并恶嗪-4-酮(11q), 其中7p在分离过程中失去甲醇分子给出2-(4-硝基苯基)-3H-吲哚-3-酮(10p)。     

Heinz‐type inequality and bi‐Lipschitz continuity for quasiconformal mappings satisfying inhomogeneous biharmonic equations

Let be the class of all sense‐preserving homeomorphic self‐mappings of . The aim of this paper is twofold. First, we obtain Heinz‐type inequality for (K,K′)‐quasiconformal mappings satisfying inhomogeneous biharmonic equation Δ(Δω) = g in unit disk with associated boundary value conditions and . Second, we establish biLipschitz continuity for (K,K′)‐quasiconformal mappings satisfying aforementioned inhomogeneous biharmonic equation when and are small enough.     

Synthesis of 2,2′‐Bi‐2H‐3,3′‐diaryl‐1,4‐benzothiazines from α,α‐Dibromoacetophenones and o‐Aminothiophenol

Some 2,2′‐bi‐2H‐3,3′‐diaryl‐1,4‐benzothiazines (5a–f) were synthesized from α,α‐dibromoacetophenones and o‐aminothiophenol.     

A Zariski Topology for Bicomodules and Corings

In this paper we introduce and investigate top (bi)comodules of corings, that can be considered as dual to top (bi)modules of rings. The fully coprime spectra of such (bi)comodules attains a Zariski topology, defined in a way dual to that of defining the Zariski topology on the prime spectra of (commutative) rings. We restrict our attention in this paper to duo (bi)comodules (satisfying suitable conditions) and study the interplay between the coalgebraic properties of such (bi)comodules and the introduced Zariski topology. In particular, we apply our results to introduce a Zariski topology on the fully coprime spectrum of a given non-zero coring considered canonically as duo object in its category of bicomodules. Supported by King Fahd University of Petroleum & Minerals, Research Project # INT/296.     

酚酞型聚芳醚砜——Ⅱ.侧基结构对Cardo双酚聚合反应性的影响

基于在“一步法”聚合反应过程中发现的酚酞对反应有特殊的“自催化”作用,本文合成了几种具有与酚酞类似结构的Cardo双酚,并通过对其聚合反应规律的研究,进一步探讨“自催化”作用的本质。实验结果表明,这类Cardo双酚也较普通结构双酚更易于进行异相成盐反应,表现为其聚合反应速度的明显加快。     

Control of organoclay structure in hydrocarbon polymers

Two different kinds of organoclays were prepared by mixing a pristine montmorillonite and a double‐chain ammonium salt in many different thermoplastic or elastomeric polymers. Independently of the chemical nature of the considered polymers, the obtained organoclays presented a basal spacing of 4 or 6 nm, when the mixing occurred in the absence or in the presence of a small amount of stearic acid (SA), respectively. X‐ray diffraction and Fourier transform infrared measurements support the hypothesis that these two kinds of organoclays correspond to paraffin‐type tilted and perpendicular bi‐layer intercalates, respectively. The co‐intercalation of SA molecules with the double‐chain amphiphile is suggested, to explain the observed expansion of the clay interlayer distance. The obtained results suggest an easy way to control the organoclay structure in polymer composites. Moreover, the authors on the basis of these results propose a criticism to the extensive literature that systematically explains most d basal spacing increase observed for clays in polymer with the penetration of apolar polymer chains in the clay interlayer space. Copyright © 2010 John Wiley & Sons, Ltd.