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401.
Galina Abramova Juerg Schefer Nadir Aliouane Martin Boehm German Petrakovskiy Alexandr Vorotynov Mikhail Gorev Asya Bovina Vladimir Sokolov 《ChemInform》2015,46(22):no-no
Single crystals of the α-MnS-based FexMn1-xS (x = 0-0.3) solid solutions are prepared and shown to be new Mott materials with the rock salt structure. 相似文献
402.
Alexandr M. Pinchuk Svetlana A. Kovalyova Sergey P. Ivonin Anatoliy S. Merkulov Tamara N. Kudrya Alexandra A. Chaikovskaya Andrey A. Tolmachev 《Heteroatom Chemistry》2001,12(7):641-651
2‐(3‐Methyl‐1,3‐diazabuten‐1‐yl)‐3‐ethoxycarbonylthiophenes are phosphorylated with phosphorus(III) halides in basic media at position 5 of the thiophene ring. Up to three heteroaromatic substituents can be introduced one by one at the same phosphorus atom. On this basis, mono‐, bis‐, and trishetaryl substituted P(III) and P(V) derivatives have been obtained. Phosphorylated 2‐(N,N‐dimethylformamidino)‐3‐ethoxycarbonylthiophenes provide a synthetic access to phosphorylated thienopyrimidines. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:641–651, 2001 相似文献
403.
Sergey P. Ivonin Andrew A. Tolmachev Alexandra A. Chaikovskaya Tamara N. Kudraya Andrew A. Anischenko Eduard B. Rusanov Alexander N. Chernega Alexandr M. Pinchuk 《Heteroatom Chemistry》2001,12(7):658-664
The reaction of phosphorus tribromide with phenylhydrazones of heterocyclic aldehydes leads to formation of a new phosphorus‐containing heterocyclic system—heterocondensed 1,2,3‐diazaphosphorines. Properties of the phosphorus‐containing heterocyclic compounds that have been synthesized are described. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:658–664, 2001 相似文献
404.
Ivan I. Zakharov Vladimir A. Zakharov Alexandr G. Potapov Georgii M. Zhidomirov 《Macromolecular theory and simulations》1999,8(3):272-278
The electronic structure and geometry of polymethylaluminoxane (MAO) [—Al(CH3)O—]n with different size (n = 4–12) have been studied using quantum‐chemical DFT (density functional theory) calculations. It has been found: 1) Starting from n = 6, the three‐dimensional oxo‐bridged (cage) structure of MAO is more stable than the cyclic structure. 2) Both for cage structure and for cyclic structure the Lewis acidity of Al atoms characterized by their net positive charge amplifies with increasing size of MAO (n). 3) Trimethylaluminium (AlMe3) reacts with the cage structure of MAO with cleavage of an Al‐O dative bond and formation of acidic tri‐coordinated Alv and basic di‐coordinated Ov atoms in the MAO molecule. Two molecules AlMe3 are associated with acidic Alv and basic Ov centers. As the MAO increases in size, the acidity of Alv centers amplifies and the distance Alv‐(AlMe3) shortens; on the contrary, interaction of AlMe3 with Ov centers weakens and the distance Ov‐(AlMe3) increases with increasing n value. The total heat of Al2Me6 interaction with MAO (sum interaction of Alv‐(AlMe3) and Ov‐(AlMe3)) noticeably decreases as the size of MAO increases (from 50.9 kcal/mol for n = 4 to 20.2 kcal/mol for n = 12). It is proposed that acidic Alv and basic Ov centers formed in the cage structure of MAO interact with zirconocene yielding ‘cation‐like’ zirconium active centers. 相似文献