一类酶反应底物的光化学荧光研究

研究了对位取代酚类酶反应底物的光化学荧光反应机理，指出光子不仅可以取代过氧化物酶，而且可以取代氧化剂（Ｈ_２Ｏ_２）。用于测定多种酶反应底物，结果满意。     

Photochemical Degradation of the UV Filter Octyl Methoxy Cinnamate Probed via Laser-Interfaced Mass Spectrometry

Octyl methoxycinnamate (OMC) is a common UVA and UVB filter molecule that is widely used in commercial sunscreens. Here, we used gas-phase laser photodissociation spectroscopy to characterise the intrinsic photostability and photodegradation products of OMC by studying the system in its protonated form, i.e., [OMC·H]⁺. The major photofragments observed were m/z 179, 161, and 133, corresponding to fragmentation on either side of the ether oxygen of the ester group (m/z 179 and 161) or the C–C bond adjacent to the ester carbonyl group. Additional measurements were obtained using higher-energy collisional dissociation mass spectrometry (HCD-MS) to identify fragments that resulted from the breakdown of the vibrationally hot electronic ground state. We found that the m/z 179 and 161 ions were the main fragments produced by this route. Notably, the m/z 133 ion was not observed through HCD-MS, revealing that this product ion is only produced through a photochemical route. Our results demonstrate that UV photoexcitation of OMC is able to access a dissociative excited-state surface that uniquely leads to the rupture of the C–C bond adjacent to the key ester carbonyl group.     

Studies on the Determination of the Micro Components by Photochemical Kinetics

The iodides can be oxidated to iodine by O_2 in air because of their lower redox potential. In an acidic solution, this reaction can be accelerated by ultraviolet light. Because the iodine yielded from potassium iodide by light irradiating solution can react with other oxidizer components, the iodine is constantly consumed. When it arrives the terminal points of the reaction, the iodine appears. According to the reaction time of the iodine appearing the quantities of the components are determined. And the terminal points can be pointed out by the blue of the iodine-starch or potentiometric     

异长春花苷内酰胺的光化学降解

报道了异长春花苷内酰胺在水溶液中经自然光照射后, 发生光氧化反应, 主要降解产物为(3S)-短小蛇根草苷. 采用通入氧气和日光灯照射的方法可加速异长春花苷内酰胺光降解, (3S)-短小蛇根草苷的产率为56%.     

硫代乙酰胺光化学反应机理的理论研究

用B3LYP, MP2和CASSCF方法, 采用cc-pVDZ和6-31++G**基组, 研究了硫代乙酰胺在基态和最低三态上消除硫化氢以及其它光解离反应, 并考虑了单个溶剂分子参与反应对质子迁移反应的影响, 得到了消除硫化氢反应的反应机理, 计算结果可以很好地解释实验结果. 进而用CASSCF方法计算了第一激发单态上的各驻点, 以及各交叉点. 计算结果表明, 在S1和T1态上发生除分子内转动以外的化学反应的可能性比较小, 当分子被激发到S2态上时, 将通过S2/S1交叉点到S1态, 在S1态上的分子有两条途径去活化, 通过S1/S0交叉点到热基态, 通过S1/T1交叉点系间窜越到T1态. 因而得出CH3CSNH2发生光解离反应的可能性不大. 基于此, 可将硫代酰胺结构引入蛋白或多肽中, 有望在不破坏分子整体结构的情况下对其进行光化学研究.     

Significance of Photosensitized Oxidation of Alkanes During the Photochemical Degradation of Petroleum Hydrocarbon Fractions in Seawater

Abstract

A crude oil hydrocarbon fraction was photooxidized as a surface film on seawater under simulated environmental conditions. After irradiation, gas chromatography and gas chromatography/mass spectrometry analyses allowed to demonstrate the presence of relatively high quantities of compounds deriving from the photosensitized oxidation of n-alkanes, pristane and phytane, being among the non-acidic photoproducts of this fraction. The results suggest that the photochemical degradation of alkanes should be considered in studies of the fate of petroleum crudes in the marine environment.     

环己硅烷类液晶化合物的量子化学研究

运用AM1和PM3两种SCF-MO方法，通过能量梯度全优化计算，给出20种环己硅烷类（苯基乙烷系）液晶化合物的稳定几何构型、电子结构和基本性质．联系有机电子结构理论进行了细致的讨论．     

Synthetic Studies on the Synthesis of Some New Fused Heterocyclic Compounds Derived from 3,5‐Pyrazolidinedione

Condensation of 1‐phenylpyrazolidine‐3,5‐dione 1 with 3‐formylchromone afforded 4‐(chromenylmethylene)pyrazolidinedione 2 , which was reacted with hydrazine or hydroxylamine in different molar ratios and conditions to give the corresponding pyrazole and isoxazole derivatives 3 ‐ 8 , respectively. Compound 2 was subject to react with ammonia, N,S‐ or S,S‐acetals, mercaptoacetic acid, cyanoacetamide or cyanothioacetamide to give the corresponding pyridine, dithiine, thiazine and thiophene, 9 ‐ 14 , respectively. The reaction of compound 2 with thiourea, guanidine, cystamine, o‐aminothiophenol, ethylenediamine, o‐phenelenediamine or barbituric acid afforded the corresponding thiazine, pyrimidine, thiazepine, diazepine, and pyran derivatives 17 ‐ 23 , respectively. The study of the reaction of compound 2 with nucleophiles via chromene ring opening was investigated.     

取代环己硅烷类(苯基乙烷和联苯基乙烷系列)液晶化合物分子的基本性质的量子化学研究

取代环己硅烷类液晶化合物是以专利形式报道的一类新型液晶材料.它们具有能降低液晶的粘度和双折射率,使液晶显示器件的响应速度增快,视角变宽等优良性能,可满足在低温下正常工作的要求,具有良好的应用前景[1].关于该类化合物的分子结构和基本性质的实验和理论研究的报道并不多见.因此,开发优良的分子轨道计算方法研究液晶化合物的结构和性质的关系已成为理论化学家们关注的课题,其中,AM1[2]法和PM3[3]法是目前被较多地用于这类研究的半经验分子轨道近似计算方法.     

无外加催化剂条件下芳香醛与活性亚甲基化合物的缩合反应和迈克尔加成反应

在DMF溶剂中,不外加催化剂使芳香醛(1)与2,2-二甲基-1,3-二氧六环-4,6-二酮(2)发生缩合反应生成2,2-二甲基-5-芳亚甲基-1,3-二氧六环-4,6-二酮(3a～f)。在同样条件下,芳香醛与5,5-二甲基-1,3-环己二酮(4)则发生缩合和迈克尔加成反应生成2,2’-芳亚甲基双(3-羟基-5,5-二甲基-2-环己烯-1-酮)(5a～h)。用单晶X-射线分析法确定了产物5b的晶体结构。     

Studies on Synthesis and Biological Activities of Novel Triazole Compounds Containing 1,3-Dioxolane

IntroductionTriazole compounds have attracted muchattention having been used as high efficient andwide spectrum fungicide and plant growthregulator[1— 4] .The triazole compounds containtintg1 ,3- dioxolane have the remarkable prevention ofthe control over plant diseases[5] .Propiconazol anddifenoconazole are two important representatives.But the necessary intermediate for synthesizingpropiconazol depends on imports,which leads tothe cost of production and application too high.According to th…     

Photochemical behaviour of propranolol in environmental waters: the hydroxylated photoproducts

The UV irradiation of propranolol, one of the beta-blockers currently used in cardiac medicine, was studied. During irradiation, the samples were analysed by LC/MS/MS, using a Waters Symmetry C₁₈ (3.5?µm 150?×?2.1?mm) column. The main photoproducts were identified from mono-, di- and tri-hydroxylation of the propranolol naphthalenic skeleton. Hydroxyl group positions were predicted by means of theoretical calculations. Partial charge calculations of the propranolol atoms predicted the formation of four mono-hydroxylated compounds, two of them being the most probable. From these two compounds, three di-hydroxylated compounds were predicted. Then the calculations from the two most probable di-hydroxylated compounds were used to propose three tri-hydroxylated propranolol compounds. It was found that the same hydroxylated photoproducts are formed in pure water and in treatment plant waste water.     

Photochemical addition of methanol to V60:Formation of 1,4-dimethoxyfullerene

The addition of methanol to C60 in the presence of acetylglycine (AG) was carried out under irradiation.The novel compound,1,4-dimethoxyl-l,4-dihydrofullerene (1),was isolated and characterized by FTIR,UV-vis,1H and 13C NMR,and FDMS.     

Fe_2O_3掺杂TiO_2薄膜对甲基紫溶液光催化降解

甲基紫是一种相当稳定的有机物 ,能被 Ti O2 光催化降解 .本文采用 sol-gel工艺在玻璃表面制得了均匀透明的 Ti O2 薄膜 ,研究了热处理温度、涂覆层数、掺杂 Fe2 O3 等制备工艺 ,以及溶液 p H值和助催化剂H2 O2 等因素对 Ti O2 薄膜的光催化性能和稳定性的影响 .结果表明 ,掺 Fe2 O3 的 Ti O2 薄膜对甲基紫的降解率明显优于未掺 Fe2 O3 的 Ti O2 薄膜 .     

吲哚类新主体化合物的固相光化学合成及包结性能研究

对苯二甲醛、对甲醛基苯甲酸甲酯和邻硝基苯甲苯醛与吲哚的固相光反应得到５种新产物，其中４种产物具有很好的包结能力。产物１、２、３和４与丙酮、乙酸乙酯、四氯化碳、氯仿分别形成１：１、１：２或２：１包结络合物１ａ，２ａ，３ａ，４ａ和４ｂ。并对包结络合物１ａ，２ａ和３ａ进行了Ｘ射线衍射结构解析。     

对位取代苯磺酸钠在溶液及界面的光反应研究

用自旋捕捉－ＥＳＲ方法研究了对位取代苯磺酸在水溶液中光化学行为，结果表明ｐＨ的改变及半导体胶体的存在都能影响其光解过程，使产生的中间体发生变化，发生光解过程中产生的中间体之一是硫中心自由基ＳＯ＾－３，在一定的ｐＨ范围还有Ｃ中心自由基和氢自由基生成，在较低ｐＨ范围，初始反应速率与ｐＨ值呈指数关系。     

1-苯基-3-甲基-5-吡唑啉酮与二羰基化合物的固相反应研究

报道了苯偶酰及其衍生物、对二甲氨基苯偶姻、邻苯二甲酰亚胺与1-苯基-3-甲基-5-吡唑啉酮的固相热反应研究;这个热反应以较高的选择性生成1:1缩合产物的一种异构体,通过IR、^{1HNMR、MS和元素分析确定了新产物的结构,并通过X射线衍射分析确定了其中一个产物的构型。}     

Kinetics and Mechanism of the Pudovik Reaction

Abstract

The kinetics and the mechanism of the Pudovik reaction for the series of α, β-unsaturated carbonyl compounds have been studied. The factors which determine the addition locoselectivity and the reactivity of the hydrophosphoryl and unsaturated compounds in this process are established. The qualitative and quantitative relationships obtained allow to predict the reaction rate and its direction depending on the reagents structure and also on the nature of catalyst and solvent used.     

不同供氢底物用于测定H2O2的酶催化动力学研究

研究了牛血红蛋白(hemoglobin,Hb)作为过氧化物模拟酶,以酸性铬蓝K、罗丹明B、亚甲基蓝不同供氢底物测定H2O2的酶催化反应体系的催化特性和反应条件。探讨了采用不同底物测定时的催化反应机理。用于雨水中H2O2含量的测定,结果满意。