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71.
Three unsymmetrical tetradentate Schiff base ligands, H2salipn, H2salipn-Br4 and H2salipn-Cl2, have been synthesized from the typical condensation reactions of treating 1,2-diaminopropane with salicylaldehyde, 3,5-dibromosalicylaldehyde and 5-chlorosalicylaldehyde, respectively. Treatment of [RuCl2(PPh3)3] with one equivalent of H2salipn or H2salipn-Br4 in the presence of triethylamine in tetrahydrofuran (THF) afforded the corresponding ruthenium(III) complexes [RuIIICl(PPh3)(salipn)] (1) and [RuIIICl(PPh3)(salipn-Br4)] (2). Interaction of [RuHCl(CO)(PPh3)3] with one equivalent of H2salipn-Cl2 or H2salipn-Br4 under the same conditions led to isolation of ruthenium(II) complexes [RuII(CO)(PPh3)(salalipn-Cl2)] (3) and [RuII(CO)(PPh3)(salalipn-Br4)] (4), respectively, in which one of the imine bonds was nucleophilically attacked by hydride to result in the formation of a mixed imine-amine ligand. The molecular structures of 1?1.5CH2Cl2, 2, 3?0.5CH2Cl2 and 4 have been determined by single-crystal X-ray crystallography. The electrochemical properties of 1–4 were also investigated. Their cyclic voltammograms displayed quasi-reversible Ru(IV)/Ru(III) and Ru(III)/Ru(II) couples with Eo ranging from 0.67 to 1.05 V and 0.74 to 0.80 V vs. Ag/AgCl (0.1 M), respectively. 相似文献
72.
Reactions of ketenes generated from alpha-diazoketones with a series of acyclic and cyclic imines were investigated under both microwave and photoirradiation conditions. The results indicate that the zwitterionic azabutadiene-type intermediates yielded from imines and ketenes undergo a conrotatory ring closure exclusively to produce beta-lactams. It is notable that no Woodward-Hoffmann product was found under the ultraviolet irradiation. The photoirradiation-induced Staudinger reaction shows a different stereoselectivity from the electrocyclic reaction of substituted 1,3-butadiene. 相似文献
73.
电化学免疫分析法研究进展 总被引:27,自引:8,他引:27
电化学免疫分析法是将免疫分析与电化学分析技术相结合的一种免疫分析新方法,近十多年来,电化免疫分析的研究有了迅速的发展。本文对电化学的免疫分析法的标记物、免疫方法、电化学检测技术进行了概括总结,并展望了电化学免疫分析的发展前景。 相似文献
74.
Lys(z)-NCA was synthesized in the presence of triphosgene, amphiphilic triblock copolymers poly(N^c-CBZ-Lysine)-PEG-poly(N^c-CBZ-Lysine) were synthesized in DMF using amino-end ended PEG as initiator with the mechanism of anion ring opening polymerization. The structures of block copolymers were characterized by IR, ^1H-NMR,GPC and DSC. The results showed triblock copolymers with expected structure and low polydispersity in molecular weight could be synthesized by this method. At the same time, the self-assembling behaviors of block copolymer were investigated by TEM. A novel helical aggregates were found to be formed in DMF. Because of biocompatibility of two components of block copolymers, these block copolymers have potential applications in the field of biomaterials. 相似文献
75.
双马来酰亚胺增韧研究Ⅱ.链扩展双马来酰亚胺及其树脂的合成及表征 总被引:6,自引:0,他引:6
合成了一系列结构不同和链长短不一的双马来酰亚胺,并对其结构和性能作了表征,同时研究了它们的固化反应和固化产物的性能。用双马来酰亚胺和二烯丙基化合物反应制造了增韧树脂,研究了该树脂的固化和热稳定性。 相似文献
76.
The stabilization modification of the halogen end groups of polystyrene prepared by atom transfer radical polymerization (ATRP) has been attempted. The reaction mechanism adopted is radical chain transfer reaction, and iso-propylbenzene is employed as not only the chain transfer agent but also the solvent. Moreover, Cu0 is used as the acceptor of the transformed halogen atom in some experiments. As evidenced by 1H NMR analysis of the modified products, the halogen end group can really be converted into the much more stable carbon-hydrogen structure. When Cu0 is not used, the conversion of the halogen end groups rises rapidly during the early stage and the increase rate slows down after about 8 h reaction. In view of the influence of reaction temperature on the modification, the conversion increases almost exponentially with temperature in the range of 80-100 °C, and the increase rate slows down at higher temperature. 1H NMR and SEC analyses prove that the modification reaction does not destroy the polymer backbone and the molecular weights remain almost the same as those of the unmodified samples. When Cu0 is introduced, the modification reaction proceeds much rapidly, the conversion of the halogen end groups rises almost linearly at the early stage and the nearly complete (>95%) dehalogenation of the polymeric chains is observed after only 12 h reaction. However, the molecular weights rise and the polydispersities become wider after the modification, which implies that the modification is accompanied with the couple termination of the polystyrene radicals besides chain transfer reaction. Furthermore, the couple termination can be restrained at some lower catalyst concentration. Indeed, the modified polymers show improved thermal stability, the initial weight loss temperatures is increased from 196 °C to 378 °C for the linear polystyrene and from 203 °C to 261 °C for the hyperbranched polystyrene. 相似文献
77.
78.
对临床、病理、放射线或CT检查确诊的82名癌肿患者,在放疗前后和对42名健康人进行了微量元素铁、锌、铜、锰、硒,铬、钴、镍的分析。研究结果显示:1.癌肿患者血清铜、镍、锰、铬、钴的含量比健康人高,而血清锌、铁、硒的含量却比健康人低;2.血清Cu/Zn、Cr/Zn、Co/Zn、Ni/Zn的比值癌肿患者均比健康人高,而Fe、Zn、Se/Zn的比值却相反。因此,可根据血清铜升高、血清锌降低,血清铜/锌比值升高的特点。用于癌肿的早期诊断;3.癌肿患者放疔后血清铁、锌含量进一步下降,铜、锰、铬的含量也出现降低,唯有硒的含量有所上升。因此,放疗时应注意补充铁、锌、铜元素。 相似文献
79.
80.