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排序方式: 共有173条查询结果,搜索用时 31 毫秒
81.
Melanie A. Short Roger D. Sommer Alec J. Falzone Tao Huang Walter W. Weare Jennifer L. Roizen 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(6):717-722
While six‐coordinate iron(III) porphyrin complexes with pyridine N‐oxides as axial ligands have been studied as they exhibit rare spin‐crossover behavior, studies of five‐coordinate iron(III) porphyrin complexes including neutral axial ligands are rare. A five‐coordinate pyridine N‐oxide–5,10,15,20‐tetraphenylporphyrinate–iron(III) complex, namely (pyridine N‐oxide‐κO)(5,10,15,20‐tetraphenylporphinato‐κ4N,N′,N′′,N′′′)iron(III) hexafluoroantimonate(V) dichloromethane disolvate, [Fe(C44H28N4)(C5H5NO)][SbF6]·2CH2Cl2, was isolated and its crystal structure determined in the space group P. The porphyrin core is moderately saddled and the Fe—O—N bond angle is 122.08 (13)°. The average Fe—N bond length is 2.03 Å and the Fe—ONC5H5 bond length is 1.9500 (14) Å. This complex provides a rare example of a five‐coordinate iron(III) porphyrin complex that is coordinated to a neutral organic ligand through an O‐monodentate binding mode. 相似文献
82.
Amino acids have been found to participate as the amine component in the Mannich reaction with both ketones and phenols. The phenolic Mannich bases may be cyclized with sulfuric acid to 1,2-dihydro-4(3/H)isoquinolones. In the presence of thionyl chloride the same Mannich bases undergo lactonization to benz[f]-1,4-oxazepin-4(3H)ones. 相似文献
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The Synthesis of Organic Molecules of Intrinsic Microporosity Designed to Frustrate Efficient Molecular Packing
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Dr. Rupert G. D. Taylor Dr. C. Grazia Bezzu Dr. Mariolino Carta Dr. Kadhum J. Msayib Dr. Jonathan Walker Dr. Rhys Short Dr. Benson M. Kariuki Prof. Neil B. McKeown 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(7):2466-2472
Efficient reactions between fluorine‐functionalised biphenyl and terphenyl derivatives with catechol‐functionalised terminal groups provide a route to large, discrete organic molecules of intrinsic microporosity (OMIMs) that provide porous solids solely by their inefficient packing. By altering the size and substituent bulk of the terminal groups, a number of soluble compounds with apparent BET surface areas in excess of 600 m2 g?1 are produced. The efficiency of OMIM structural units for generating microporosity is in the order: propellane>triptycene>hexaphenylbenzene>spirobifluorene>naphthyl=phenyl. The introduction of bulky hydrocarbon substituents significantly enhances microporosity by further reducing packing efficiency. These results are consistent with findings from previously reported packing simulation studies. The introduction of methyl groups at the bridgehead position of triptycene units reduces intrinsic microporosity. This is presumably due to their internal position within the OMIM structure so that they occupy space, but unlike peripheral substituents they do not contribute to the generation of free volume by inefficient packing. 相似文献
89.
A. J. Short 《Foundations of Physics Letters》2001,14(3):275-284
Application of the uncertainty principle to conditional measurements is investigated and found to be valid for measurements on separated sub-systems. In light of this, an apparent violation of the uncertainty principle obtained by Kim and Shih in their realization of Popper's experiment [1] is explained through analogy with a simple optical system. 相似文献
90.
An introduction to our recent work (hep-th/0104212) on the (G ×G-invariant) principal chiral model with boundary is presented. We found that both classically integrable boundary conditions
and quantum boundary is presentedS-matrices were classified by the symmetric spacesG/H.
Presented at the 10th International Colloquium on Quantum Groups: “Quantum Groups and Integrable Systems”, Prague, 21–23 June
2001. 相似文献