首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18篇
  免费   0篇
化学   9篇
晶体学   2篇
力学   1篇
数学   4篇
物理学   2篇
  2019年   1篇
  2018年   1篇
  2016年   2篇
  2015年   1篇
  2013年   4篇
  2012年   1篇
  2011年   3篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2004年   1篇
  2002年   1篇
排序方式: 共有18条查询结果,搜索用时 46 毫秒
1.
A new vic-dioxime, 13,14-bis-(hydroxyimino)-9,12,15,18-diazadithiaoctacosane, has been synthesized from 2-octylsulfanylaminobenzene and (E,E)-dichloroglyoxime. Mononuclear transition metal complexes of NiII, CuII, CoII and FeII have been prepared and were found to have a metal–ligand ratio of 1:2. The synthesis of di- and trinuclear complexes was achieved with UIVO2 and CuII depending on the stoichiometry of the reactants. The complexes were characterized by elemental analysis, 1H-n.m.r., u.v.–vis, i.r., f.a.b.-m.s. and by cyclic voltammetry.  相似文献   
2.
3.
Some growth conditions of the resolvent function of a Banach space operator are investigated using higher order Cesàro means. More precisely, Abel and Nevanlinna estimates are obtained under the condition of boundedness of some weighted Cesàro averages. Also, certains results related to the (strong or uniform) convergence of Cesàro means are mentioned.  相似文献   
4.
The synthesis of α'-acyloxy-α,β-unsaturated cyclic ketones from the corresponding α,β-unsaturated cyclic ketones by using manganese (III) acetate in combination with 2-chloropropionic acid followed by subsequent Arbuzov and intramolecular Horner-Emmons cyclization reactions provided a convenient synthetic pathway to various butenolides 4a-d.  相似文献   
5.
A new complex of diaquabis(5-methoxyindole-2-carboxylato)bis(3-picoline)nickel(II) (Ni(5-MeOI2CA)2(3-pic)2(H2O)2), was synthesized for the first time and characterized by elemental analysis, FT-IR and electronic spectroscopy (UV-Vis) and single-crystal X-ray diffraction (XRD) techniques. The thermal degradation of the Ni(II) complex was investigated using thermogravimetric and differential thermal analyses techniques in oxygen atmosphere. The molecular structure of the complex was determined by single crystal X-ray diffraction technique. Hirshfeld surface analysis (HSA) investigated the packing modes and intermolecular interactions in molecular crystals, as they provide a visual picture of intermolecular interactions. In addition, all computational studies at B3LYP/6-311++G(d,p) were carried out for theoretical characterization of Ni(II) complex. The optimized geometry results, which were well represented the X-ray data, were shown that the chosen of DFT/B3LYP/6-311++G(d,p) was a successful choice for title compound. After a successful optimization, FMOs, chemical activity, non-linear optical properties (NLO), molecular electrostatic potential (MEP), Mulliken population (MPA), natural population analyses (NPA), Fukui function analysis (FFA) and natural bond orbital analysis (NBO), which could not obtained by experimental ways, were calculated and investigated. The computed of net charges and chemical activity studies which helped to identifying the electrophilic/nucleophilic nature.  相似文献   
6.
Önder  Zerrin  Çanak  İbrahim 《Positivity》2019,23(4):891-919
Positivity - In this paper, we obtain some Tauberian conditions in terms of slow oscillation and slow decreasing in certain senses, under which convergence of a double sequence in...  相似文献   
7.
8.
In this study we investigate the spectrum and regularized trace of the second order differential operator equation with periodic boundary conditions.  相似文献   
9.
10.
Reaction of cyclic β‐dicarbonyl compounds such as pyrimidine‐(1H,3H,5H)‐2,4,6‐trione (BA), 1,3‐dimethyl pyrimidine‐(1H,3H,5H)‐2,4,6‐trione (DMBA) and 2‐thioxo‐pyrimidine‐(1H,3H,5H)‐4,6‐dione (TBA) with cyanogen bromide in acetone and 2‐butanone in the presence of triethylamine afforded a new class of stable heterocyclic spiro[furo[2,3‐d]pyrimidine‐6,5′‐pyrimidine]2,2′,4,4′,6′(3H,3′H,5H)‐pentaones (dimeric forms of barbiturate) at 0 °C and ambient temperature. Structure elucidation was carried out by X‐ray crystallographic, 1H NMR, 13C NMR, two dimensional NMR, FT‐IR spectra, mass spectrometry and elemental analysis. The mechanism of product formation is discussed. The reaction of DMBA with cyanogen bromide in the presence of triethylamine also afforded trimeric form of barbiturate of uracil derivatives in good yield. The reaction of selected acyclic β‐dicarbonyl compounds with cyanogen bromide in the presence of triethylamine in acetone and/or diethyl ether has also been investigated under the same condition. Diethyl malonate and ethyl cyanoacetate brominated and also ethyl acetocetate both brominated and cyanated on active methylene via cyanogen bromide.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号