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1.
2.
We fill a gap in [4], and provide a rigorous example of a local ringR whose Jacobson radical is locally nilpotent, butM
2(R) is not strongly π-regular.
The online version of the original article can be found at
The work of the first author was partially supported by the DGICYT (Spain), through the grant PB92-0586, and by the Comissionat
per Universitats i Recerca de la Generalitat de Catalunya. 相似文献
3.
Reaction of lithium enolates of simple ketones with (+/-)-phenyl vinyl sulfoxide has potential for the convergent construction of complex fused ring systems containing a bicyclo[n.2.0]alkan-1-ol. The formation of sulfinylbicyclo[4.2.0]octan-1-ols 1-3 from the lithium enolate of cyclohexanone with (+/-)-phenyl vinyl sulfoxide or (R)-(+)-p-tolyl vinyl sulfoxide 18 was used to probe the mode of this novel cyclization reaction. Using phenyl vinyl sulfoxide, variations in the reaction lighting and solvent were investigated, in conjunction with radical trapping (TEMPO) and isotope labeling (deuterium) experiments. Cyclization to form sulfinylbicyclooctanols 1-3 is likely to proceed via an intermediate that ring closes to the bicycloalkanol anion 11 and was presently favored by the use of solvents such as THF or DME. 相似文献
4.
Melvyn Rowen Churchill Clifford Bueno David A. Young 《Journal of organometallic chemistry》1981,213(1):139-150
The species FeRu3(CO)13(μ-PPH2)2, synthesized from Ru3(CO)12 and Fe(CO)4(Ph2PPPh2),has been characterized both spectroscopically and via a single-crystal X-ray structural analysis. This complex crystallizes in the centrosymmetric triclinic space group P [No. 2, Ci1] with a 10.066(3), b 12.899(3), c 17.003(4) Å, α 111.89(2), β 91.02(2), γ 102.00(2)°, V 1992.7(9) Å3, Z 2, ?(obsd) 1.79(2) g cm-3 and ?(calcd) 1.82 cm-3. Diffraction data were collected with a Syntex P21 automated four-circle diffractometer and the structure was refined to RF 6.0% and RWF 3.6% for all 5213 reflections (RF 3.8%, RWF 3.6% for those 4140 reflections with |Fo|> 3σ(|Fo|).The metal atoms define a planar triangulated rhombus, with atoms Ru(1) and Ru(2) at the bridgehead, and Fe(1) and Ru(3) at the acute apices. Fe(1) is linked to four terminal carbonyl ligands and is associated with the heteronuclear bonds Fe(1)Ru(1) 2.861(1) Å and Fe(1)Ru(2) 2.868(1) Å. The ruthenium atoms are each bonded to three terminal carbonyl groups. The retheniumruthenium distances are Ru(1)Ru(2) 3.098(1), Ru(1)Ru(3) 3.147(1), and Ru(2)Ru(3) 3.171(1) Å. The structure is completed by Ph2P bridges across the Ru(1)Ru(3) and Ru(2)(ru(3) vectors (<Ru(1)P(1)Ru(3) 84.89(5)° and <Ru(2)P(2)Ru(3) 85.56(6)°). 相似文献
5.
Dr. Tim Schleif Dr. Jörg Tatchen Julien F. Rowen Frederike Beyer Prof. Dr. Elsa Sanchez-Garcia Prof. Dr. Wolfram Sander 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10452-10458
The Cope rearrangement of selectively deuterated isotopomers of 1,5-dimethylsemibullvalene 2 a and 3,7-dicyano-1,5-dimethylsemibullvalene 2 b were studied in cryogenic matrices. In both semibullvalenes the Cope rearrangement is governed by heavy-atom tunneling. The driving force for the rearrangements is the small difference in the zero-point vibrational energies of the isotopomers. To evaluate the effect of the driving force on the tunneling probability in 2 a and 2 b , two different pairs of isotopomers were studied for each of the semibullvalenes. The reaction rates for the rearrangement of 2 b in cryogenic matrices were found to be smaller than the ones of 2 a under similar conditions, whereas differences in the driving force do not influence the rates. Small curvature tunneling (SCT) calculations suggest that the reduced tunneling rate of 2 b compared to that of 2 a results from a change in the shape of the potential energy barrier. The tunneling probability of the semibullvalenes strongly depends on the matrix environment; however, for 2 a in a qualitatively different way than for 2 b . 相似文献
6.
Wedderburn’s factorization of polynomials over division rings is refined and used to prove that every central division algebra
of degree 8, with involution, has a maximal subfield which is a Galois extension of the center (with Galois group Z2⊕Z2⊕Z2). The same proof, for an arbitrary central division algebra of degree 4, gives an explicit construction of a maximal subfield
which is a Galois extension of the center, with Galois group Z2⊕Z2. Use is made of the generic division algebras, with and without involution.
This work was supported by the Israel Committee for Basic Research and the Anshel Pfeffer Chair. 相似文献
7.
8.
Louis Halle Rowen 《Israel Journal of Mathematics》1982,41(3):213-234
A general example of cyclic division algebra is given, based on a construction of Brauer, yielding examples of division algebras
of arbitrary prime exponent without proper central subalgebras, and also noncrossed products of arbitrary exponent.
This research was supported in part by the U.S.-Israel Binational Science Foundation.
An erratum to this article is available at . 相似文献
9.
在前文工作的基础上,结合MNDO/EHMO分子轨道方法和自然杂化轨道方法,具体计算了CC键和CP键的核自旋偶合常数.计算结果表明,1JCC和1JCP主要由成键原子的轨道杂化作用和键极性这两种结构因素所决定.为从简单价键理论角度解释和计算1JCC和1JCP值提供了简便直观的方法. 相似文献
10.
We develop necessary and sufficient conditions for central simple algebras to have involutions of the first kind, and to be
tensor products of quaternion subalgebras. The theory is then applied to give an example of a division algebra of degree 8
with involution (of the first kind), without quaternion subalgebras, answering an old question of Albert; another example
is a division algebra of degree 4 with involution (*) has no (*)-invariant quaternion subalgebras.
The research of the second author is supported by the Anshel Pfeffer Chair.
The third author would like to express his gratitude to Professor J. Tits for many stimulating conversations. 相似文献