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91.
Two multidentate ligands: N,N′-di-(propionic acid-2′-yl-)-2,9-di-aminomethylphenanthroline (L1) and N,N′-di-(3′-methylbutyric acid-2′-yl-)-2,9-di-amino-methylphenanthroline (L2) were synthesized and fully characterized by 1H NMR and elemental analysis. The binding ability of L1 and L2 to metal ions such as M(II) (M = Cu, Zn, Co and Ni) and Ln(III) (Ln = La, Nd, Sm, Eu, and Gd) has been investigated by potentiometric
titration in aqueous solution and 0.1 mol dm−3KNO3 at 25.0 ± °C. In view of the structure of L1 and L2, mononuclear metal complexes can be formed in solution. The stability constants of binary complexes of ligands L1 and L2
with metal ions M(II) and Ln(III) have been determined respectively and further discussed. 相似文献
92.
从一种聚芳酯B-N得到了丝状(包括细丝和粗丝)、纹影状和大理石纹状等与小分子向列液晶相似的多种织构。由于样品淬火后晶片装饰在织构上而不影响分子取向矢的分布,因而可以用化学刻蚀和电镜技术揭示其向错和取向矢图。电镜和光学显微镜的结果相互补充,表明了细丝和粗丝状织构的分子取向矢分布很不相同,是两种不同的织构,而粗化始于第二熔融降温。在这些向列织构中分别发现了S=±(1/2)和s=+1的向错的例子和平面内微区转向壁的证据。 相似文献
93.
Two‐dimensional (2D) organic nanomaterials are attracting increasing research interest and expected to be the ideal candidate for future‐ proofed flexible electronics and biotechnologies. Owing to the complex molecular structures and multiple intermolecular interactions in organic systems, deeper understanding of rational molecular design and assembly principles is urgently required. In this review, a collection of molecular packing mode in the 2D organic nanomaterials via supramolecular assembly is presented, so as to help explicit the relationship among molecular structures, supramolecular interactions and molecular packing motifs in 2D assembly systems. We also provide a rational and accessible schematic model to demonstrate several typical kinds of molecular packing motifs for the prediction of the 2D morphology. 相似文献
94.
95.
96.
Three-dimensional quantum mechanical calculations for vibrational predissociation of HeI2(B) van der Waals molecules are presented using the time-dependent wave packet technique within the golden rule approxima tion.The total and partial decay widths,lifetimes,rates and their dependence on initial vibrational states were obtained for HeI2 at low initial vibrational excited levels.Our calculations show that the calculated tota decay widths,lifetimes and rates agree well with those extrapolated from experimental data available The predicted total decay widths as a function of initial vibrational states exhibit highly nonlinear behavior.The very short propagation time (less.than 1 ps) required in the golden rule wave packet calculation is determined by the duration time of the final state inter-action between the fragments on the vibrationally deexcited adiabatic potential surface.The final state interaction between the fragments is shown to play an important role in determining the final rotational distri 相似文献
97.
Two new C18-norditerpenoid alkaloids from Aconitum delavayi 总被引:2,自引:0,他引:2
Shan Hao Jiang Hai Qing Wang Yi Ming Li Shuang Jun Lin Jun Jie Tan Da Yuan Zhu 《中国化学快报》2007,18(4):409-411
Further phytochemical investigation of the unique C18-norditerpenoid alkaloids from the roots of Aconitum delavayi Franch ledto the isolation of two new norditerpenoid alkaloids,delavaconitine F 1 and delavaconitine G 2.Their structures were determinedfrom spectroscopic evidence. 相似文献
98.
Hai Bing LI Yuan Yin CHEN* Shu Ling GONG Department of Chemistry Wuhan University Wuhan 《中国化学快报》2002,13(3)
Calix [n] arenas {n = 4, 6 or 8} are easily prepared from formaldehyde and para-substituted phenols via cyclic condensation under alkaline conditions in one step. It is not surprising that the calyx [n] arene (n = 4, 6, 8) chemistry has been developing very rapidly during the latest 20 years1. However, it is not the case for calixarenes with odd benzene rings (for example, n = 5). The yield of p-tert-butylcalix [5] arene synthesized in one-step from p-tert-butylphenol and formaldehyde was a… 相似文献
99.
Shan Qian Li Hai Lei Tang Jin Cheng Yang Yong Wu 《中国化学快报》2007,18(3):261-262
An optically active intermediate 5 for A-ring of 19-nor-1a,25-dihydroxyvitamin D3 2 has been synthesized in five steps, starting from readily available, inexpensive D( )-xylose 6 with good yield. 相似文献
100.
Mohammad A. Hai Nigel W. Preston Rolf Kyburz Emanuel Schpp I. Ralph C. Bick Manfred Hesse 《Helvetica chimica acta》1980,63(7):2130-2134
Aristoserratine, a New Indole Alkaloid from Aristotelia serrata W.R.B. OLIVER and from A. peduncularis (LABILL .) HOOK . F. The new indole alkaloid aristoserratine (2) has been isolated from Aristotelia. Its structure and absolute configuration were elucidated on the basis of spectroscopic data. 相似文献