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五十年代,核磁共振技术开始应用于化学中,显示了它的强大的生命力。六十年代,随着核磁共振在有机化学中的广泛应用,核磁共振技术的飞速发展,它的研究对象及应用范围也日益扩大。在有机化合物中,磁性核有 H~1,C~(13),F~(19),P~(31),N~(15),B~(11),……等。其中,H~1是最重要的,也是研究最多的,是有机分子的重要结构分析工具。此外,F~(19)及 P~(31)等在各有关实验室中也有很多研究。但是,对于组成有机分子骨架的碳原子说来,却有困难,因为 C~(12)的磁矩等于零,没有核磁共振现象。只有碳的一个同位素 C~(13)是有磁性的。因此,测C~(13)的核磁共振直接研究碳骨架的想法长期以来具有 相似文献
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从1963年发现闭二碳代十二硼烷[Carborane(C_2B_(10) H_(12) ,下简称碳十硼烷)]以来,碳硼烷化学得到了迅速的发展,它不但在理论上有重要意义,而且已经在实际上得到了应用,特别是作为耐高温、耐辐射(吸收中子)的合成材料,脑瘤放射治疗以及作为固体推进剂组分. 相似文献
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2(?)2'-苯并噻唑偶氮(?)邻苯二酚(简称BTAPC)作为金属离子的显色剂已有研究,但与Fe(Ⅱ)的显色反应尚未见报道。本文参考TAPC合成方法合成了该试剂,研究了它的性能和Fe(Ⅱ)的显色反应,实验结果表明:BTAPC与Fe(Ⅱ)在pH8.5~10.5范围内,在Tritonx-100存在下,形成稳定的络合物,操作简便,方法灵敏,应用拟定的分析方法,测定了试样中微量铁,获得满意的结果。 相似文献
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(一)Trypargine(1)是1882年从非洲树蛙Kassina Senegalensis 中分离到的皮肤毒素,LD_(50)为16.9 mg/kg(大鼠静脉给药)。据报道,它具有抑制乌贼鱼神经轴素钠通道的作用。Schimizu 小组曾报道过(±)和(-)Trypar-gine(1)的合成。这是迄今为止仅有的二条合成路线。在这里我们报道了一条采用我们在研究钩吻素子全合成中所发展的一种立体 相似文献
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采用溶解度等温法研究了La(ClO_4)3-C_(11)H_(12)2ON_2(安替吡啉)-H_2O三元体系在0℃时的相平衡,并由此合成了La(C_(11)H_(12)ON_2)_6(ClO_4)_3配合物。还确定了该配合物的制备条件,测定了它的一些性质,并对其结构作了初步分析。 相似文献
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应用溶胶-凝胶法制备了Ce_(0.8)Sm_(0.2)O_(1.9)固体电解质粉体,通过X射线衍射对所制备的电解质粉体进行了物相分析。研究表明,Sm2O3已经固溶到CeO_2中形成了具有萤石结构CeO_2基固溶体。经成型并在1450℃下烧结2 h获得致密的Ce_(0.8)Sm_(0.2)O_(1.9)固体电解质。通过组装含有氧离子阻塞电极电池(-)致密Al2O3,Pt|Ce_(0.8)Sm_(0.2)O_(1.9)(SDC)固态电解质|Pt,O2(+)测试空气中不同温度下的电子电导。应用扫描电子显微镜观察所制备试样的微观组织形貌,结果表明:制备的电解质组织致密,高温粘合剂、电解质及刚玉坩埚结合紧密,保证了阻塞电极的气密性。采用Hebb-Wagner离子阻塞电极法测定了Ce_(0.8)Sm_(0.2)O_(1.9)在空气气氛下的电子导电性。结果显示:在测量温度范围内Ce_(0.8)Sm_(0.2)O_(1.9)固体电解质的电子电导率在1×10-8~1×10-6m S·cm-1之间,经计算得出活化能的平均值为0.9885 e V。 相似文献
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磺化聚苯乙烯/聚吡咯复合膜 总被引:1,自引:0,他引:1
磺化聚苯乙烯(SPS)/聚吡咯(PPy)复合膜是通过毗咯单体在SPS基体中原位聚合方法制成的.用FTIR研究SPS/PPy复合膜分子间的相互作用,特别是SPS中SO3阴离子在1200cm-1不对称伸缩振动港带的分裂,说明了聚吡咯是以阳离子的形式作用于SPS中SO3阴离子上,产生强的离子-离子相互作用.同时还研究了在复合过程中,引起SPS基体的微区结构与性能的变化.SPS由于吡咯单体的胀入和聚合,导致了SPS微相分离,复合膜在动态力学性能测试中出现了两个Tg转变,分别在124和145℃. 相似文献
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PREPARATION, CHARACTERIZATION AND ELECTROCHEMICAL PROPERTIES OF POLYPYRROLE-POLYSTYRENE SULFONIC ACID COMPOSITE FILM 总被引:1,自引:0,他引:1
Polypyrrole-polystyrene sulfonic acid (PPy-PSSA) composite films have been electrosynthesized in an aqueous solution of PSSA. The electro-active films exhibit cation exchange during the redox process. Infrared, Raman and energy-dispersive spectroscopic results demonstrated that the polyanion of PSS^- is co-deposited into the PPy matrix and couldn‘t be stripped from the film extensively by dedoping. The doping level together with dipolaron content of the PPy-PSSA composite film increases during electrochemical polymerization process. SEM images revealed that the composite film has smooth and compact morphology and AFM pictures suggested that PPy chains are possibly grown perpendicular to the electrode surface. TGA tests indicated that the composite films has much better thermal stability than that of pure PPy.Furthermore, electrochemical studies showed that the relaxation process at certain holding potential has great effect on the shape of the cyclic voltammetric curves of PPy-PSSA composite film. The composite film exhibits cation and anion exchange during the redox process after undergoing the relaxation step. It is more difficult for divalent anion to enter the polymer matrix than a univalent ion, and a large cation such as (CH3CH2CH2CH2)4N^ cannot be involved in the ion exchange process. 相似文献
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5,10,15,20—四(对—乙酯苯基)卟啉LB膜的结构 总被引:1,自引:0,他引:1
对卟啉类化合物LB膜的结构、电性质和气敏性的研究已见报道。本文利用膜天平和UV-Vis分光光度计研究了标题化合物在气-液界面上的成膜特性、分子间相互作用和LB膜的结构。5,10,15,20-四(对-乙酯苯基)卟啉(TPEPP)由5,10,15,20-四(对-氰苯基)卟啉和乙醇酯化得到。元素分析测定值与计算值相符。λ(CHCl_3,nm):421,515,550,590,645;ν(KBr压 相似文献
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Wampler RD Zhou M Thompson DH Simpson GJ 《Journal of the American Chemical Society》2006,128(34):10994-10995
The nonlinear optical activity of bacteriorhodopsin (bR) Langmuir-Blodgett (LB) films were investigated computationally and experimentally. The second harmonic generation optical rotary dispersion (SHG-ORD) response was calculated directly from the known structure and orientation of the PSB retinal chromophore within bR with no adjustable parameters. The predicted results agree remarkably well in sign, magnitude, and trend with the experimental SHG-ORD measurements. The calculations indicated negligible chirality with the tensor for the PSB retinal chromophore, but significant chiral-specific activity for the thin film through a relatively simple orientational mechanism. 相似文献
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J. Mu X. S. Feng J. Y. Li K.Z. Yang T. F. Chen L. Jiang 《Journal of Dispersion Science and Technology》2013,34(3):243-249
Dispersion characteristics of the monomolecular films of hematoporphyrin mixed with stearic acid has been studied. The average molecular areas of mixed monolayers coincided approximately with the ideal additivity rule when the“solid” films were extrapolated to zero surface pressure. The orientation of the macrocycles was given by infrared dichroism with the tilting angle of 10. 1° to the plane of the film. The SERS of LB films deposited on silver island films was observed- The results showed that there are two possible contribution, i. e., electromagnetic and chemical interaction between the hematoporphyrin molecules and Ag island films. 相似文献
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研究了两亲性卟啉5,10,15,20-四-(4-N,N,N-二甲基十六烷基氨基苯基)卟啉(TDMC16PP)在气/液界面上的成膜性能,制备了其多层LB膜。用UV-Vis吸收光谱、荧光光谱、偏振UV-Vis吸收光谱和小角X射线衍射对LB膜进行了测试表征。结果表明:两亲性卟啉TDMC16PP具有良好的成膜性能,其LB膜性质稳定,有较好的结构均匀性和周期性。在LB膜内,脂肪链并不是直立的,卟啉大环平面与基片平面成42.5°排列。 相似文献