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1.
合成了系列Dawson结构钨钒磷杂多化合物,并用IR,NMR等手段对其结构进行了表征,考察了这类杂多化俣物对苯酚过氧化氢羟的活性,探讨了反应机理。  相似文献   

2.
郭玲  武海顺  金志浩 《结构化学》2004,23(8):918-925
用密度泛函理论(DFF)的B3LYP方法,在6-311G^ 水平上对AIPm和AIPm^-(m=2~9)团簇的几何构型,电子结构和振动频率等性质进行了理论研究,给出了一种以P朋团簇作为设计AIPm类结构的母体,考虑在不同位置上结合Al原子的结构,可以较快找到AIPm类团簇基态结构的方法.通过对基态结构的第一离解能和能量二次差分讨论,得到m为奇数的AIPm团簇比m为偶数的稳定,对基态结构的HOMO-LUMO能隙和绝热电子亲合势的讨论表明,AIP3^-,AIP5和AIP7团簇结构较稳定。  相似文献   

3.
采用量子化学B3LYP/6-31G方法,分别优化;计算了MPV三种异构体的几何和电子结构,结果表明,在异构体中反式结构为平面构型,顺式结构为非平面构型,反式结构增加可使异构体的UV最大吸收峰有规则红移,解释了实验现象,并对烷氧基取代聚对苯乙炔中的顺、反异构其对相关性质的影响进行了有益的讨论。  相似文献   

4.
刘磊 《物理化学学报》1998,14(5):391-393
根据遗传算法的基本原理,建立了一种优化分子几何结构的理论计算程序,对用Lennard-Jones势描述的惰性气体分子LJ38的结构进行了优化计算,并进一步计算了其结构的拓扑指数.结果显示出LJ38分子基态结构具有奇特的和文献报等不一致的反常拓扑性质.  相似文献   

5.
CdS和CdSe新型纳米结构的高效溶剂热合成   总被引:1,自引:0,他引:1  
钭建宁  郭睿倩  彭波  韦玮  黄维 《无机化学学报》2006,22(10):1766-1770
采用快速高效的溶剂热法合成了海星形CdS纳米结构和一维CdSe纳米结构。用XRD、SEM和UV-Vis等表征手段对产物进行了表征,结果表明产物为单一的CdS和CdSe纳米结构,且CdS纳米结构具有良好的分散性,其形成极大地受到pH值影响,而CdSe先形成层状的二维结构、再形成一维纳米结构。  相似文献   

6.
噻菁染料的合成及吸收光谱的研究   总被引:1,自引:0,他引:1  
闫文鹏  彭必先 《有机化学》1994,14(5):492-498
合成了阳离子型、两性离子型和阴离子型的噻菁染料,对它们的结构进行了表征,并研究了染料的结构(阴离子和取代基的改变) 对吸收光谱的影响。  相似文献   

7.
含Sn—N键的混合三烃基锡氮杂环化合物的研究   总被引:1,自引:0,他引:1  
杨志强  周秀中 《合成化学》1995,3(4):323-328
报道了15个含Sn-N键的混合三烃基锡环衍生物合成及结构表征。随含氮杂环的不同。化合物分别是五配位的聚合结构和四配位的单体结构,对化合物的质谱作了较为详细的讨论,测定了化合物的生物活性,并对生物活性与结构的关系进行了讨论。  相似文献   

8.
用密度泛函方法研究了LaCn及La2Cn(n=-1,0,+1)分子簇的结构和稳定性.对La2Cn体系,提出了两种可能构型,其中一种具有C2v对称性,另一种具有D∞h对称性.计算结果表明,对La2Cn,当n=+1,-1时,线状结构最稳定,并且在n=+1时,C2v结构极不稳定有收敛向线状结构的趋势.而当n=0时,C2v结构最稳定.最后还计算了LaC和La2C分子簇的电子亲和势和离化能.  相似文献   

9.
对PtO2/Al2O3催化剂进行了氟化处理及添加稀土金属氧化物的改性研究,考察了它们对乙炔和甲基二氯硅烷的硅氢加成反应的催化活性影响.并以IR、XRD、TPR及比表面积测定的方法,对氟改性前后的催化剂及载体进行了表征.结果表明,载体氟改性后较好地提高了催化剂的催化反应活性,其原因在于改变了载体的表面结构,增强了载体上的正电中心强度,从而增加了强中心上铂离子的比率,但没有改变其骨架结构,也没有形成新的晶相结构.  相似文献   

10.
报道了15个含Sn一N键的混合三烃基锡氮杂环衍生物的合成及结构表征。随含氮杂环的不同,化合物分别是五配位的聚合结构和四配位的单体结构。对化合物的质谱作了较为详细的讨论。测定了化合物的生物活性,并对生物活性与结构的关系进行了讨论。  相似文献   

11.
穆劲  李建业  杨孔章 《化学学报》1994,52(6):535-539
制备了嵌有血卟啉的硬脂酸LB膜, 结果表明, 血卟啉分子镶嵌在硬脂酸间分子膜内, 在混合LB膜中血卟啉分子之间未发生强的相互作用, 其大环平面为倾斜取向。  相似文献   

12.
Deuteroporphyrin and hematoporphyrin as complete methyl esters and their complexes with iron(III) were synthesized and characterized by NMR and electronic spectroscopy. For the first time the changes of the specific heat capacity of these solid biological objects with temperature were investigated by the method of differential scanning calorimetry. These parameters are shown to be smooth functions of temperature in the range 290–360 K, indicating the absence of the phase transitions in these systems.  相似文献   

13.
以氯化血红素(Ⅰ)为原料,经过溴化氢-冰醋酸加成反应、羟基亲核取代反应和无水氯化氢催化酯化反应制得3,8-双-(1-羟基乙基)次卟啉二甲酯(Ⅲ),然后通过琼斯试剂氧化反应制备了3,8-双乙酰基次卟啉二甲酯(Ⅳ)。 考察了血红素与溴化氢-冰醋酸饱和溶液反应过程中温度和时间对3,8-双-(1-羟基乙基)次卟啉二甲酯(Ⅲ)产率的影响;改进了酯化反应的实验条件;选用了廉价易得、选择性较好的羟基选择性氧化剂。 实验结果表明,当反应温度为35 ℃、反应时间为25 h时,血卟啉(Ⅱ)的产率最高,为98.5%;当催化剂为无水氯化氢时产物(Ⅲ)的产率最高,为72.1%;使用琼斯试剂做氧化剂使实验成本大大降低。 通过1H NMR、MS和IR测试技术对产物结构进行了表征。  相似文献   

14.
The hematoporphyrin derivative YHPD, a China-made product, has been clinically used in photodynamic therapy of tumors as a good photosensitizing drug. The NMR study on the structure of its major components is reported here. In terms of high performance liquid chromatography (HPLC) four major components A, B, C and D were isolated. The NMR results showed that the component A is O-acetylhematoporphyrin, B and C are two isomers of vinyldeuteroporphyrin. The spectra of 2-dimensional homonuclear correlation NMR, 2-dimensional NOE (nuclear overhauser enhancement), ~(13)C-NMR and off-resonance as well as FAB (fast atom bombarding) mass spectrum of component D indicate that it is a protoporphyrin dimer linked by carbon-carbon bond. This finding may providea chemical basis for understanding the difference in biological activity between YHPD and other foreign commercial HPD, as well as the composition of clincally used alkali-treated HPD and its effective component.  相似文献   

15.
NMR study on the major components in hematoporphyrin derivative YHPD   总被引:1,自引:0,他引:1  
The hematoporphyrin derivative YHPD, a China-made product, has been clinically used in photodynamic therapy of tumors as a good photosensitizing drug. The NMR study on the structure of its major components is reported here. In terms of high performance liquid chromatography (HPLC) four major components A, B, C and D were isolated. The NMR results showed that the component A is O-acetylhematoporphyrin, B and C are two isomers of vinyldeuteroporphyrin. The spectra of 2-dimensional homonuclear correlation NMR, 2-dimensional NOE (nuclear overhauser enhancement), 13C-NMR and off-resonance as well as FAB (fast atom bombarding) mass spectrum of component D indicate that it is a protoporphyrin dimer linked by carbon-carbon bond. This finding may provide a chemical basis for understanding the difference in biological activity between YHPD and other foreign commercial HPD, as well as the composition of clinically used alkali-treated HPD and its effective component.  相似文献   

16.
通常对于带侧链羧基的卟啉,是以其酯的形式在CDCl3溶液中测量核磁共振谱的。与之相反,本文直接提供血卟啉、原卟啉和卟啉C在酸性溶液中的质子谱和碳-13谱。这种途径有利于这些医用卟啉的结构鉴定和生产监控。  相似文献   

17.
Absorption and fluorescence properties of hematoporphyrin derivative in different solvent systems are investigated. The presence of a large amount of stable aggregates is demonstrated. The existence of these aggregates represents one major difference between hematoporphyrin derivative and hematoporphyrin free base.  相似文献   

18.
The oligomeric composition of HpD, Photofrin II and other hematoporphyrin derivatives useful for the diagnosis and therapy of tumors has been studied. Gel chromatographic procedures were used that excluded porphyrin aggregation. Photofrin and hematoporphyrin derivatives were shown to contain different quantities of monomer, dimer and other oligomeric porphyrins.  相似文献   

19.
Abstract— Synthesis of the tumor-localizing preparation HPD (hematoporphyrin derivative) results in the formation of dimers and oligomers of hematoporphyrin joined by labile linkages. Studies with HPD and an HPD analog containing the chlorin analog of mesoporphyrin suggest the presence of two different linkages, either of which yields a tumor-localizing product. One such linkage is apparently derived from a hematoporphyrin-based oligomer present in commercial preparations of hematoporphyrin as an impurity. The other linkage is formed during the chemical steps leading to the conversion of hematoporphyrin to "HPD".  相似文献   

20.
A long-lived transient with a lifetime of several hundred microseconds was observed following the flash photolysis of aqueous solutions of hematoporphyrin buffered at pH 7.5. The transient-ground state difference absorption spectrum was determined 500 microseconds after flash photolysis. The yield of this species was found to increase with increasing hematoporphyrin concentration and it was also found to depend on the excitation wavelength. The lifetime of the species is not significantly affected by the presence of oxygen. Because the triplet state of hematoporphyrin is not the only long-lived species produced by flash photolysis of aqueous hematoporphyrin solutions, the observed triplet state extinction coefficients will be lower than the true value and hence the triplet state yields of hematoporphyrin determined by the flash photolysis, "complete conversion" technique, are only upper limits. The formation of the long-lived species is discussed in terms of electron transfer between the monomer partners in hematoporphyrin dimer and aggregates which are present in aqueous solutions of hematoporphyrin, particularly in concentrated solutions.  相似文献   

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