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1.
生理液中血卟溶液状态的光谱研究   总被引:2,自引:2,他引:0  
本文通过对血卟啉在生理条件下(pH=7.2,I=0.5mol/L NaCl)水溶液中的光谱变化研究,探讨了其在溶液中的聚集状态。应用Kasha理论推算出血卟啉二聚体的面-面间距离为0.528n铐,面间角为20^o,平衡常数为2.85×10^-6,研究了在光作用下,血卟啉-人血清白蛋白溶液体系的光谱特性。讨论了光谱特性与血卟啉在癌瘤光化学治疗机制间的关系。  相似文献   

2.
亚甲蓝双分子聚集体的解离平衡   总被引:4,自引:1,他引:4  
何锡文  冯喜增 《分析化学》1995,23(12):1381-1385
本通过光主地研究了作为新的光敏剂-亚甲蓝(Methylne Blue,MB)在水溶液中的溶液状态,以及其在不同温度时双分子聚集体的解离平衡,通过差示光谱监测了亚甲蓝在水溶液中,其双分子二聚体在温度30-60℃范围内的构成方式的变化:其单分子倾角9α)为48.3-46.1°,双分子面间距离(r)为0.576-0.580nm,监测了亚甲蓝在水溶液中其单最大吸收波长吸收值随温度的变化,算得其二聚体的解  相似文献   

3.
光敏剂亚甲蓝与不同溶剂的相互作用研究   总被引:7,自引:0,他引:7  
应用光谱法研究了新光敏剂亚甲蓝在不同溶剂中的电子光谱特性,通过Kasha理论推测了其在不同溶剂中二聚体的分子构造模式,其二聚体的面-面间距离为1.345~1.425nm,面间角为82.9°~87.5°确认由McRae式对亚甲蓝与不同溶剂间的相互作用下方式进行评价是可行的,提出了亚甲蓝在不同溶剂中分子间力的相互结合作用导致亚甲蓝在溶液中的结构变化,产生光谱差异的原因,阐述了溶液状态与选择性分子间力的  相似文献   

4.
生理液中血卟啉溶液状态的光谱研究   总被引:1,自引:0,他引:1  
本文通过对血卟啉在生理条件下(pH=7.2,I=0.5mol/LNaCl)水溶液中的光谱变化研究,探讨了其在溶液中的聚集状态。应用Kasha理论推算出血卟啉二聚体的面-面间距离为0.528nm,面间夹角为20°,平衡常数为2.85×10-6.研究了在光作用下,血卟啉-人血清白蛋白溶液体系的光谱特性,讨论了光谱特性与血卟啉在癌瘤光化学治疗机制间的关系。  相似文献   

5.
用光谱法研究了光敏剂血卟啉在水溶液中的聚集状态,并以胶束作为生物膜模型,探讨了血卟啉在胶束介质中的聚集状态状态变化,用原子力显微镜研究了血卟啉聚集状态的微观结构及其在胶束介质中的聚集状态。  相似文献   

6.
光动力学疗法是应用光敏剂受激光激发后对靶体产生光化学作用来治疗病变。光漂白是光动力学治疗过程中普遍现象,在光动力疗法治疗血管类疾病中,光敏剂与血浆中的生物分子相互作用及其在血管中的光漂白行为直接关系到治疗效果。本文考察了HB和THB与血浆的作用和在血浆溶液中的光漂白过程,研究表明在富氧条件下,以单重态氧漂白为主;在有血浆生物分子溶液中光产物与水溶液中的光产物不同。研究表明光敏剂的结构和氧化电位导致了它们不同的光漂白机制,HB和THB与生物分子的相互作用加速了它们光漂白并影响了光产物。  相似文献   

7.
用分光光度滴定法在25.0℃时测定了不同pH值下α-,β-,γ-环糊精以及1mol/L NaOH水溶液中α-和β-环糊精双核铜配合物与4-取代苯酚形成超分子配合物的稳定常数。化学计量法表明,主体环糊精及环糊精双核铜配合物与客体4-取代苯酚形成了1:1的超分子配合物。从主-客体间的尺寸关系、pH值、多点识别和诱导契合作用等因素讨论了环糊精及环糊精双核铜配合物对客体4-取代苯酚的分子识别机制。结果表明  相似文献   

8.
水溶液中亚甲蓝分子聚集状态的研究   总被引:3,自引:0,他引:3  
用分光光度法研究了亚甲蓝(MB)染料在水溶液中的聚集状态及其与表面活性剂的相互作用,讨论了无机盐对亚甲蓝在阴离子表面活性剂溶液中聚集状态的影响。推导了水溶液中亚甲蓝单体和二聚体的动态平衡关系式。利用计算机程序不仅求出了与作图法结果非常接近的MB单体的摩尔吸光系数和聚合平衡常数,而且求出了MB二聚体的摩尔吸光系数及相应浓度下MB单体所占的比例系数。  相似文献   

9.
多胺修饰β-环糊精对铝-铁试剂荧光体系的增敏作用   总被引:1,自引:0,他引:1  
赵焱  刘育 《分析化学》2002,30(3):276-279
研究了β-环糊精(1)、单-[6-乙二胺-6-脱氧]-β-环糊精(2)、单-[6-(二乙烯三胺)-6-脱氧]-β-环糊精(3)和单-[6-(三乙烯四胺)-6-脱氧]-β-环糊精(4)对铝-铁试剂荧光体系的增敏作用。实验结果表明:加入β-环糊精及其衍生物后体系的荧光强度均增强,增敏率为4>3>2>1,其中4给出最大的荧光增敏率。研究了pH值在3.0-7.5之间酸度对主体化合物增敏能力的影响,发现体系的pH值对β-环糊精的增敏率影响较小,而随着体系酸性的增强,多胺修饰β-环糊精的增敏作用显著增强。探讨了修饰环糊精引入边臂的长度和主-客体间的尺寸适合等因素对铝-铁试剂体系荧光增敏率的影响。  相似文献   

10.
β—环糊精和α—萘乙酸包络物的荧光光谱研究   总被引:5,自引:0,他引:5  
本文研究了水溶液中β-环糊精和α-萘乙酸包络反应,研究了包络物的荧光光谱性质,测定了包络物的形成常数,讨论了各种水溶性一元醇对该包络物形成及荧光性质的影响,并对其应用了作了预测。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

13.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

14.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

15.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

16.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

17.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

18.
19.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.  相似文献   

20.
Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.  相似文献   

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