Corrole光敏剂在光动力治疗中的重原子效应

最近, 我们合成了一系列Corrole衍生物, 经过鼻咽癌(Nasopharyngeal carcinoma,NPC) 细胞的体外PDT试验后, 筛选出了一个具有优良PDT活性的Corrole光敏剂. 本文报道该类Corrole光敏剂在PDT中的重原子效应.     

Application of an integrated microchip system with capillary array electrophoresis to optimization of enzymatic reactions

In this work, a combination of complementary metal-oxide semiconductor (CMOS) microchip system with capillary array electrophoresis (CAE) is demonstrated as a system for optimizing conditions for enzymatic reaction. Dimethylacridinone (DDAO)-phosphate substrate and alkaline phosphatase conjugate were selected for the enzymatic reaction, which was applicable to the enzyme-linked immunosorbent assay (ELISA) technique. Laser-induced fluorometry with a miniature semiconductor laser was used to detect the enzymatic products. The speed of the enzymatic reaction between the DDAO-phosphate and the alkaline phosphatase conjugate was investigated as a function of reaction time. The microchip-CAE detection system could determine the pH condition and the concentration of enzyme that are suitable for rapid and low-cost analysis. This result shows the feasibility of using the microchip-CAE system for application to miniaturized screening systems.     

Next-generation quantum theory of atoms in molecules for the photochemical ring-opening reactions of oxirane

The conical intersections corresponding to the C─O and C─C ring opening were optimized and the reaction paths traversing these intersections were obtained. Investigation of the C─O ring opening revealed that when traversing the lowest energy conical intersection, the reaction path returns to the closed ring geometry. The C─O path traversing the intersection featuring torsion of terminal CH₂ group however, led to a ring-opened geometry, an H-shift and the formation of acetaldehyde that can undergo further dissociation. The observation of different reaction paths was explained by the 3-D paths from quantum theory of atoms in molecules (QTAIM) that defined the most preferred direction of electronic motion that precisely tracked the mechanisms of bond breaking and formation throughout the photo-reactions. The size, orientation, and location of these most preferred 3-D paths indicated the extent and direction of motion of atoms, bonds, and the degree of torsion or planarity of a bond indicating a predictive ability.     

Kinetics of heterogeneous recombination of hydrogen atoms on solid surfaces

Heterogeneous recombination rates of hydrogen atoms on solid surfaces were measured for the first time. An anomalous form of these curves testifies that the reaction on surfaces of metals, semiconductors and dielectrics follows a universal mechanism with participation of preadsorbed atoms.     

An analysis on the transmission of electron density through sulphur atoms in the quaternization reactions of benzothiazoles

The kinetics of quaternization of a number of 2-substituted benzothiazoles with alkyl iodides and phenacyl bromide have been studied in nitrobenzene. The order of reactivity of different substituted benzothiazoles has been found to be -H > NO₂ > Cl. The relative reactivity of 2-amino and 2-methyl derivatives has been ascribed to a solvation phenomenon. The analysis of rho values from the Hammett equation suggests two possible routes for the transmission of electron density.     

盐酸胍对反胶束中RNase A活性的影响

以胞嘧啶核苷酸2',3'-环单磷酸酯为底物研究了变性剂盐酸胍对十二胺丁酸盐-环己烷反胶束溶液中核糖核酸酶A活性的影响,同水溶液相比,盐酸胍对反胶束中酶活性的抑制作用很小。反胶束的大小限制了酶分子天然态构象的改变,从而保证了其活性中心的完整性。核糖核酸酶A的内源荧光研究发现,同水溶液相比,反胶束中蛋白的最大发射波长没有发生变化,但荧光偏振极化度增加,也表明了在反胶束中酶分子的运动自由度较在水溶液中有所降低。     

The use of hydrophilic groups in aqueous organic reactions

The representative examples of beneficial effects of hydrophilic groups in aqueous organic reactions are described, including the Diels-Alder reactions, hetero Diels-Alder reactions, Claisen rearrangement, radical reactions, and transition metal-catalyzed reactions. Although the low solubility of organic molecules in water has been a bane in aqueous organic reactions, the incorporation of hydrophilic groups into the substrate structure can overcome the solubility problem and at the same time enhance the hydrophobic effect. In some cases, interesting micellar effects are observed because of the amphiphilic natures of such molecules. The emerging concept of "removable hydrophilic group," in which the solubility problems have been alleviated, yet the initial product can still be transformed into a variety of products with the removal of the hydrophilic groups, is also described.     

Magneto-chiral Nonlinear Optical Effect with Large Anisotropic Response in Two-Dimensional Halide Perovskite

The chiral organic–inorganic halide perovskites (OIHPs) are vital candidates for superior nonlinear optical (NLO) effects associated with circularly polarized (CP) light. NLO in chiral materials often couples with magnetic dipole (MD) transition, as well as the conventional electric dipole (ED) transition. However, the importance of MD transition in NLO process of chiral OIHPs has not yet been well recognized. Here, the circular polarized probe analysis of second harmonic generation circular dichroism (SHG-CD) provides the direct evidence that the contribution of MD leads to a large anisotropic response to CP lights in chiral OIHPs, (R-/S-MBACl)₂PbI₄. The thin films exhibit great sensitivity to CP lights over a wide wavelength range, and the g-value reaches up to 1.57 at the wavelength where the contribution of MD is maximized. Furthermore, it is also effective as CP light generator, outputting CP-SHG with maximum g-factor of 1.76 upon the stimulation of linearly polarized light. This study deepens the understanding of relation between chirality and magneto-optical effect, and such an efficient discrimination and generation of CP light signal is highly applicable for chirality-based sensor and optical communication devices.     

Successive substitution of halogen atoms in 4, 6-dihaloquinolines in palladium-catalyzed reactions with amines and arylboronic acids

A procedure was developed for the synthesis of 4,6-diamino- and 4,6- or 6,4-arylaminoquinolines by palladium-catalyzed C-N- and/or C-C-cross-coupling of 6-bromo-4-chloroquinoline.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 210–214, January, 2005.     

Inhibition and enhancement of glucose oxidase activity in a chitosan-based electrode filled with silver nanoparticles

A chitosan-based electrode filled with silver nanoparticles (AgNPs) and glucose oxidase (GOD) was used as an enzyme electrode to investigate the effect of aging process of AgNPs on the GOD activity. Freshly prepared AgNPs inhibit the GOD activity, however, the inhibitory effect decreased with the increase of aging time. After aged for a period of time, AgNPs showed enhancement effect on the GOD activity. The effect of aging was studied by the measurements of Ag⁺ ions concentration, zeta (ζ) potential and X-ray photoelectron spectroscopy (XPS). And the results indicated that the concentration of Ag⁺ ions in the silver sol decreased during the aging period (i.e. Ag⁺ ions converted to more inert silver metal Ag⁰). The effect of AgNPs on the GOD activity can be changed by controlling the aging time of AgNPs. This research provides a new and simple approach to mediate AgNPs property, which is of great value in potential application of AgNPs in biosensors and nanoscale devices.     

Kinetics of hydrated electron reactions with phosphate anions: a laser photolysis study

The decay kinetics of hydrated electron (e_aq ⁻) formed upon photolysis of aqueous solutions of sodium pyrene-1,3,6,8-tetrasulfonate at λ = 337 nm in the presence of phosphate anions (up to 2 mol L⁻¹) was studied by nanosecond laser-pulse photolysis in a wide range of pH (3.5–10) and ionic strength (I, up to 2 mol L⁻¹) values. At high pH values, where the HPO₄ ²⁻ ions dominate, the e_aq ⁻ decay kinetics depends only slightly on phosphate concentration (rate constant for the reaction is at most 2·10⁵ L mol⁻¹ s⁻¹). The H₂PO₄ ⁻ ions react with e_aq ⁻ at a rate constant of 2.8·10⁶ L mol⁻¹ s⁻¹ (I = 0), which increases linearly with the parameter in accordance with the Debye-Hückel theory. The rate constant for quenching of e_aq ⁻ by H₃PO₄ at pH ≤ 4 decreases linearly with the parameter due to the secondary salt effect and equals 1.6·10⁹ L mol⁻¹ s⁻¹ at I = 0. The logarithm of the rate constant for quenching of e_aq ⁻ by phosphates is linearly related to the number of the O-H bonds in the phosphate molecule. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1277–1280, July, 2007.     

掺杂阴离子对电化学合成的聚邻甲苯胺性质的影响

邻甲苯胺在酸性介质中的聚合速率与酸的种类有关,聚合速率影响了各种掺杂阴离子聚合物膜的形态,聚合物的电导率、循环伏安曲线形状受掺杂阴离子的影响,其电容量与掺杂阴离子的种类及形态有关,阴离子的种类对电极电位和紫外-可见光谱无影响。     

非水介质中的酶催化反应

介绍了非水溶剂体系中的酶催化反应，主要是反胶束体系中酶催化反应和脂肪酶催化反应的新研究成果，评述了各溶剂体系中酶的结构，动力学特征，稳定性及活性。     

The exchange reaction of hydrogen atoms in the system sterically hindered hydroxylamine-nitroxyl radical

The rate constants of the direct and reverse exchange reactions of the hydrogen atom in the system sterically-hindered nitroxyl radical-hydroxylamine of the quinoline, imidazoline, pyrrolidine, and piperidine series as well as diarylhydroxylamine were determined. A scale of the reductive abilities of the hydrolamines was established. A low value of the isotope effect is typical of the reactions of hydrogen exchange in the systems hydroxylamine-nitroxyl radical. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1324–1328, July, 1998.     

Free radicals in vicarious C-amination reactions of 1-methyl-4-nitropyrazole

The primary radical anions of substrate in the reactions of vicarious nucleophilic substitution of hydrogen in 1-methyl-4-nitropyrazole with 1,1,1-trimethylhydrazinium iodide and 4-amino-1,2,4-triazole in t-BuOK-DMSO were observed and identified by EPR monitoring. The probable mechanism of the substrate radical anions formation is discussed.     

Theoretical approach to the mechanism of reactions between halogen atoms and unsaturated hydrocarbons: the Cl + propene reaction

The potential energy surface for the Cl + propene reaction was analyzed at the MP2 level using Pople's 6-31G(d,p) and 6-311+G(d,p), and Dunning's cc-pVDZ and aug-cc-pVDZ basis sets. Two different channels for the addition reaction leading to chloroalkyl radicals and five alternative channels for the abstraction reaction leading to C(3)H(5) (.) + HCl were explored. The corresponding energy profiles were computed at the QCISD(T)/aug-cc-pVDZ//MP2/aug-cc-pVDZ level of theory. Theoretical results suggest that the previously established mechanism consisting of (1) direct abstraction and (2) addition-elimination steps is instead made up of (1) addition through an intermediate and (2) two-step abstraction processes. No direct abstraction mechanism exists on the potential energy surface. The kinetic equations derived for the new mechanism are consistent with the pressure dependence experimentally observed for this reaction.     

Effect of fluorine replacement of hydrogen atoms in aromatic compounds on magnetic shielding of nuclei of heavy atoms at a distance from position of substitution

Conclusions From¹³C,¹⁵N,¹⁷O,¹⁹F,²⁹Si,³¹P,⁷³Ge,⁷⁷Se,¹¹⁹Sn, and¹²⁵Te NMR data, it follows that complete replacement of phenyl hydrogen atoms by fluorine in compounds C₆H₅X leads to a systematic increase in shielding of nuclei in the ring carbon atom bonded to the X group and in shielding of the nucleus of the -atom of X, along with deshielding of the nuclei of the - and -atoms of X. The effect evidently has a long-range character and can be described by the extended theory of Dewar and Kelemen.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 829–832, April, 1989.     

Use of bioluminescent bacterial sensors as an alternative method for measuring heavy metals in soil extracts

The luminescence based bacterial sensor strains Pseudomonas fluorescens OS8 (pTPT11) for mercury detection and Pseudomonas fluorescens OS8 (pTPT31) for arsenite detection were used in testing their application in detecting heavy metals in soil extracts. Three different soil types (humus, mineral and clay) were spiked with 1, 100 or 500 μg g⁻¹ Hg²⁺ or As³⁺. Samples were taken 1, 14 and 30 days and extracted with water, ammonium acetate, hydrogen peroxide and nitric acid to represent water soluble, bioavailable, organic matter bound and residual fractions, respectively. The lowest mercury-concentration measured using biosensor (0.003 μg kg⁻¹) was considerably lower than by chemical method (0.05 μg kg⁻¹). The sensor strain with pTPT31 appeared to have a useful detection range similar to that of chemical methods. Concentration results with chemical and biosensor analysis were very similar in the case of mercury-spiked samples. Although some of the arsenite samples showed higher variation between methods, it is concluded that the bacteria can be used as an alternative traditional methods for different types of samples.     

Treatment of heavy metal ions in wastewater using layered double hydroxides: A review

Heavy metal ions are toxic, and their toxicities change with different valence states, charges, and radii. Among the methods used for heavy metal ion removal, adsorption is widely employed due to its low cost and simple operation. As natural anionic clays, layered double hydroxides (LDHs) have drawn considerable attention for their use in the removal of anionic pollutants (such as heavy metal anions) due to their high removal efficiency and environmental friendliness. This article reviews the effects of the charge, type, and radius of the cations in the laminates of LDHs and the anions in the LDH interlayers, as well as the charge and radius of the heavy metals and the conditions (such as pH, coexisting ions, and temperature) on removing heavy metal ions with LDHs. The removal mechanisms have also been discussed. LDHs are hugely promising as an application for removing heavy metal ions that exist in different ionic forms by controlling the type and condition of LDHs.     

Polar and solvation effects in reactions of oxygen atoms and hydroxyl and alkoxyl radicals with oxygen-containing compounds

Experimental data on the activation energies of reactions of H-abstraction from oxygencontaining compounds by oxygen atoms and hydroxyl and alkoxyl radicals in the gas and liquid phases have been analyzed by means of the parabolic model of the transition state. The contribution of polar interaction to the activation energies of the reactions has been calculated. The contribution of solvation to the activation energy has been calculated by comparison of the reaction parameters of the respective reaction in the liquid and gas phases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 38–42, January, 1994.