排序方式: 共有66条查询结果,搜索用时 62 毫秒
61.
Eshtiagh-Hosseini H Housaindokht MR Beyramabadi SA Beheshti S Esmaeili AA Khoshkholgh MJ Morsali A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(4):1341-1347
The new tetra dentate dianionic H2PS (N,N'-dipyridoxyl (1,3-propylenediamine)) Schiff-base ligand and its octahedral Co(III) salen complex [Co(PS)(H2O)(CH3OH)]+CH3COO(-) were synthesized, where coordinating atoms of H2PS (N,N,O(-),O(-)) occupied equatorial positions with H2O and CH3OH as axial ligands. The nature of the H2PS and its complex were determined by elemental and spectrochemical (IR, UV-vis, 1H NMR and Mass) analysis. Also, the fully optimized geometries and vibrational frequencies of them together with the 1H NMR chemical shifts of H2PS have been calculated using density functional theory (B3LYP) method. Obtained structural parameters are in good agreement with the experimental data reported for similar compounds. The calculated and experimental results confirmed the suggested structures for the ligand and complex. 相似文献
62.
Firouz Matloubi Moghaddam Zohreh Mirjafary Hamdollah Saeidian Salman Taheri Malihe Doulabi Mostafa Kiamehr 《Tetrahedron》2010,66(1):134-5520
An efficient, single step synthesis of hitherto unknown indole-annulated pentacyclic indolylhydroquinolines via tandem C-alkylation and intramolecular S-alkylation of indolin-2-thiones with N-alkylquinolinium salts in excellent yields (83-95%) is reported. This facile approach provides a powerful entry into polycyclic structures containing nitrogen and sulfur related to alkaloids. The structure of the product was determined by Röntgen crystal structure analysis. 相似文献
63.
A one-pot three component Biginelli condensation of different substituted aromatic and aliphatic aldehydes with ethyl acetoacetate and urea to the respective 3,4-dihydropyrimidin-2-( 1H)-ones under sol... 相似文献
64.
The model of Ouchiyama and Tanaka 1 - 3 was successfully adapted to calculate the maximum packing fraction (ϕm) of polymer latexes with varying bimodal particle size distributions based upon rheological measurements performed on its constituent parts. The values of ϕm calculated from the model can be used to predict the rheological properties of the latices. The model was experimentally validated and used for the prediction the viscosity of studied bimodal latices of known concentration using the master curve of viscosity-reduced volume fraction (η vs. ϕ/ϕm). 相似文献
65.
We classify Jordan G-tori, where G is any torsion-free abelian group. Using the Zelmanov prime structure theorem, such a class divides into three types, the Hermitian type, the Clifford type, and the Albert type. We concretely describe Jordan G-tori of each type. 相似文献
66.
Beyramabadi SA Morsali A Khoshkholgh MJ Esmaeili AA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):467-471
Three N,N'-dipyridoxyl Schiff bases (L1, L2 and L3) have been newly synthesized and characterized by IR, (1)H NMR, mass spectrometry and elemental analysis. Their optimized geometries together with the theoretical assignment of the vibrational frequencies and the (1)H NMR chemical shifts of them have been computed by using density functional theory (DFT) method. In the optimized structures of the Schiff bases, two pyridine rings are not in a same plane; however the substitutions are essentially in the same plane with the pyridine rings. Also, the benzene ring(s) in the bridge region is (are) not in the same plane with the pyridine rings and azomethine moieties. In all the species, engagement in intramolecular-hydrogen bonds causes to weakness of the phenolic O-H bonds. Consistency between the theoretical results and experimental evidence confirms suitability of the optimized geometries for the synthesized Schiff bases. 相似文献