RESONANCE RAMAN STUDIES OF BACTERIORHODOPSIN ANALOGUES

Abstract— We present the results of resonance Raman measurements on a series of bacteriorhodopsin (bR) analogues formed from synthetic retinals which have replaced the native chromophore in the active site. Specifically, 5,6-dihydro-bR, 13-desmethyl-bR, 10-methyl-bR, 14-methyl-bR, and 10.14-dimethyl-bR have been studied. All five analogues bind and form Schiff base retinal-apoprotein linkages. While the Schiff base linkages of 5,6-dihydro-bR, 13-desmethyl-bR, and 10-methyl-bR are protonated, like the native chromophore, the 14-methyl-bR, and 10,14-dimethyl-bR Schiff bases are unprotonated. These results suggest that the binding site of bacteriorhodopsin near the Schiff base moiety is different from that of rhodopsin. The protonated Schiff base -C=NH- stretching frequency of 5.6-dihydro-bR lies at 1660 cm^-1 which is unusually high for a bacteriorhodopsin based pigment. The downward shift upon deuteration is 16 cm^-1, essentially identical to that measured for bacteriorhodopsin. This and the other analogue results strongly reinforce our previous arguments that the Schiff base stretching frequency is determined in large part by two factors, the C=N force constant and the stretch interaction with C=N-H bend. On the other hand, the deuterium isotope effect is determined primarily by the stretch-bend interaction.     

化学反应的热动力学研究法进展

本文综述了近年基于Ｔｉａｎ方程建立的化学反应热动力学研究法的进展。重点评述了无量纲参教法、对比进度法、模拟热谱曲线法,特征参量法和时间变量法。     

SOME PRESUPPOSITIONS IN THE METAPHYSICS OF CHEMICAL REACTIONS

The project of chemistry to classify substances and develop techniques for their transformation into other substances rests on assumptions about the means by which compounds are constituted and reconstituted. Robert Boyle not only proposed empirical tests for a metaphysics of material corpuscules, but also a principle for designing experimental procedures in line with that metaphysics. Later chemists added activity concepts to the repertoire. The logic of activity explanations in modern times involves hierarchies of activity concepts, transitions between levels through non-dispositional groundings. Such hierarchies terminate in powerful particulars, such as elementary charged particles. Do these have a fundamental place in the most recent accounts of molecular architecture, stabilities and transformations? However, a close study of the contemporary chemistry of substances transforming reactions discloses a hybrid metaphysics, making use of both the Boylean corpuscles and Faradayan fields. This is illustrated by an analysis of the metaphysics inherent in John Polanyi’s use of “chemoluminescence” to follow the formation of products in chemical reactions. A brief sketch of a resolution of the tension between the two metaphysical schemes is drawn from Niels Bohr’s radical metaphysics extended from the quantum realm proper to chemistry (and perhaps beyond).     

PHOTOCHEMICAL REACTIONS OF CHLORPROMAZINE; CHEMICAL AND BIOCHEMICAL IMPLICATIONS

Abstract— The photoexcited chlorpromazine reacts with methanol to yield promazine and 2-methoxypromazine by two different reaction pathways: hydrogen atom abstraction and nucleophilic attack. respectively. When the photoexcitation of chlorpromazine is performed in the presence of protein or nucleic acids, chlorpromazine binds to the biopolymer. This binding is drastically pH-dependent and correlates to the phototoxic effect exhibited in chlorpromazine—photosensitization of E. coli. No photodynamic damage of E. coli attributed to CPZ-sensitization of molecular oxygen could be detected.     

CHEMICAL REACTIONS OF SUPEROXIDE ANION RADICAL IN APROTIC SOLVENTS

Abstract— While superoxide anion radical does not normally react with olefins, it does react with activated double bonds. Thus O^-₂ oxidatively cleaves certain α,β-unsaturated ketones such as chalcones and tetracyclone and electron poor olefins such as 1,1-dicyano and 1,1-dinitro olefins. Similarly O^-₂ can react with substituted nitrobenzenes to yield the corresponding nitrophenols. EPR and oxygen labeling (KO³⁶₂) experiments confirm an electron transfer mechanism.     

CHEMICAL REACTIONS IN SURFACTANT AGGREGATES

This review article summarized the research on chemical reactions in surfactant aggregates which has been carried out in China in the recent ten years.     

STUDIES ON CYCLOADDITION REACTIONS OF VINYLPHOSPHONATES WITH NITRONES

Cycloaddition reactions of vinylphosphonates with nitrones were studied. A series of 4-phosphonyl-3-aryl-N-arylisoxazolidines were synthesized by the reaction of vinylphosphonates with nitrones. The structure of 3a was confirmed by X-ray single-crystal diffraction.     

稀土四元络合物显色反应的研究

研完了稀土与铬天青S(CAS),4,7-二苯基邻菲哼啉(4,7-dp-phen)和溴化十六烷基三甲铵(CTAB)四元络合物的显色反应。测定了络合物的最大吸收峰、摩尔吸光系数及组成。当乙醇存在时,络合物λ_max略有红移,ε值普遍增大。详细地研究了CTAB浓度对四元络合物增色和退色效应以及对不同稀土四元络合物作用的差异。文中拟定了La³⁺存在时测定微量Gd³⁺的分析方法。     

TIME-RESOLVED RESONANCE RAMAN STUDIES ON THE PHOTOCHEMICAL CYCLE OF BACTERIORHODOPSIN

Abstract— Kinetic resonance Raman (RR) experiments were designed to study the time-behaviour of the retinal-binding protein bacteriorhodopsin (BR) in its photochemical cycle. The unphotolyzed chro-mophore B-570 and the two intermediates L -550 and M-412 were probed by the characteristic C=C stretching vibrations of the retinal moiety. Time resolution was achieved with a spinning cell as flow system in combination with two CW lasers in a pump-probe configuration. RR spectra were probed at 475 nm at various delay times between pump and probe event. The deconvolution of the spectra into the various components B-570, L-550 and M-412 was carried out by curve fitting procedures. It was found that at pH7.4 L-550 decays — with a time-constant of 62 μs — not completely but to a residual level of 35% of its initial value. This intermediate L -amplitude finally disappears in the ms-range (4.5 ms) synchroneously with the intermediate M -412. An analogeous time-behaviour was found at pH 4.6. In the basic range also an " L " -intermediate could be identified which is coupled to the long-lived M-component. To explain the peculiar time-dependence it is proposed that during the fast decay of L a dynamic equilibrium between L and M is established. Then during the reconstitution of B -570 the two intermediates disappear synchroneously. A molecular model is presented in which the dynamic equilibrium between L and M is explained by an oscillatory motion of a proton from the Schiff base group of the chromophore to its counterion.     

in-situ ESR AND RAMAN SPECTROSCOPIC STUDIES ON ELECTROPOLYMERIZATION OF PYRROLE

The in-situ transient ESR measurements reveal that the oxidized structure (PP++) of polypyrrole (PP) films has an electrocatalytic activity to the oxidation of pyrrole during the electropolymerization process. Surface-enhanced resonance Raman scattering (SERRS) effect was used to probe the structure of PP films in very early stages of the polymerization on gold electrodes. It is of special interest that the electropolymerization can take place at much less positive potentials (about 300 mV) under the irradiation of light. This photocatalytic effect may be applied to the pattern deposition of polymers.     

七甲茚基稀土络合物和碱金属盐的化学反应

本文用核磁共振等方法研究了稀土络合物和碱金属盐中的七甲茚基的质子化或氘化反应、亲核取代反应及络合物中稀土离子的还原反应。七甲茚基络合物比相应的茂基或茚基化合物更易与盐进行上述反应。三氘代七甲茚基在氘化反应中显示了同位素效应。     

KINETIC STUDIES OF THE TWO LIGHT REACTIONS IN PHOTOSYNTHESIS

Abstract— The decay kinetics of the photo-induced absorbance changes in red and green algae are very sensitive to the wavelength of the actinic light. A four to tenfold increase in half-decay time is noted in going from short wavelength (550–650 mμ) to long wavelength (> 700 mμ) excitation. The slow decay rates produced by long wavelength light can be enhanced with a steady background of short wavelength light. A relationship between initial decay rates and O₂ evolution rates is described. This relationship allows a direct correspondence between these spectroscopic studies and the 'red-drop' and 'enhancement' experiments of Emerson.     

单核铁配合物与过氧酸反应的研究

本文用波谱及高压液相色谱（ＨＰＬＣ）方法研究了二氯代三－２－吡啶甲基胺的铁（Ⅲ）配合物（ＦｅＴＰＡＣｌ＿２ＣｌＯ＿４），三─６─甲基─２─吡啶甲基胺合铁（Ⅱ）与苯甲酸的配合物（Ｆｅ（Ⅱ）ＴＬＡＯＢｚＣｌＯ＿４）同单过氧化邻苯二甲酸六水合镁盐（ｍｏｎｏｐｅｒｏｘｙｐｈｔｈａｌｉｃａｃｉｄ，ｍａｇｎｅｓｉｕｍｓａｌｔｈｅｘａｈｙｄｒａｔｅ，即ＭＰＰＡ）的反应。提出了过氧键的两种断裂（即均裂和异裂）机理，分析了中心离子价态、配体结构等因素对反应机理的影响；并通过ＦｅＴＰＡＣｌ＿２ＣｌＯ＿４与间氯代过氧代苯甲酸（ｍｃＰＢＡ）的反应，研究了过氧酸结构对反应机理的影响。实验结果表明：就过氧酸中过氧键发生均裂的程度而言：三价铁配合物与过氧酸的反应＞二价铁配合物与过氧酸的反应；ＭＰＰＡ反应体系＞ＭＣＰＢＡ反应体系。     

ENDOR AND ESR STUDIES OF RADICALS FORMED IN FRIEDEL-CRAFTS REACTIONS

The present study deals with the study of some Friedel-Crafts alkylating system and the accurate measurement of hyperfine coupling constants by ESR and ENDOR techniques. The results indicate that the observed ESR spectra are due to polycyclic aromatic radical cations formed from their parent hydrocarbons.It is suggested that benzyl halides produced in the Friedel-Crafts alkylating reaction undergo Scholl condensation reaction to give polycyclic aromatic hydrocarbons, which were converted into the corresponding polycyclic aromatic radical cations in the presence of aluminum chloride.     

CHEMICAL MECHANISMS OF CHEMI- AND BIOLUMINESCENCE. REACTIONS OF HIGH ENERGY CONTENT ORGANIC COMPOUNDS

Abstract— The chemistry of high energy content molecules was investigated. In particular, the mechanisms by which these compounds rearrange to generate electronically excited states was probed. A mechanism for chemiexcitation involving chemically initiated electron transfer is described. It is concluded this mechanism is applicable to many chemi- and bioluminescent processes.     

广东干草化学成分的研究

从干草中分离出五个化合物，并分别并鉴定为β－谷甾醇，香豆酸，棕榈酸，木樨草素和柯伊利素。     

醉马草化学成份的研究(Ⅰ)

醉马草(Achnatherum inebrians(Hance) Keng)是禾本科芨芨草属植物,分布在我国西北部,是牧场上一种毒草,目前有蔓延趋势。醉马草化学成份及毒理作用,国内外均未曾进行过研究。探明醉马草化学成份对发展畜牧业和医学事业都具有一定意义。     

菲涂在颗粒物上与NO_2的反应

本文研究菲涂在硅胶或烟尘上与NO_2的暗反应和光化学反应,藉色谱和GC/MS分析反应产物。暗反应以取代反应为主,主要产物是硝基菲.光反应的产物为2,2′-二甲酰基联苯、亚硝基-2-甲酰基联苯等,在UV辐照下以光氧化裂解为主。菲涂在硅胶上或涂在烟尘上与NO_2的暗反应的明显差异可能是由于吸附在硅胶上的水分子与菲对NO_2的竞争反应。产物的Ames试验指出,无致突性的菲与NO_2反应可较容易地生成有直接致突性的二次污染物,对人体健康更有危害。     

STUDIES ON THE TOPOLOGICAL PROPERTY OF POTENTIAL ENERGY PROFILE OF ELEMENTARY REACTIONS

In the present paper cusp catastrophe is used to model the topological property of poten-tial energy profile of elementary reactions, and four typical situations, which can be trans-formed into two types, have been systematically analyzed with 58 independent elementaryreactions. The main results obtained here are (i) the concept of activation energy is brieflydiscussed and extended; (ii) the reaction O+ CO→CO_2 is found to belong to type Ⅳ, not totype Ⅰ;and (iii) there may be some special correlation between α_1 and α_2. Finally the neces-sary discussions are carried out.