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141.
[reaction: see text] Substituted diphenylamines can be synthesized by Pd(0)-catalyzed N-arylation using o-nitroanilines and nitro-substituted aryl bromides for a substrate. Cyclization of the diphenylamines by various methods, including the intramolecular Pd(0)-catalyzed N-arylation, produces 2-methoxyphenazine which can easily be deprotected to give 2-hydroxyphenazine. This phenazine is required to synthesize methanophenazine, a novel redoxactive cofactor isolated from methanogenic archaea. 相似文献
142.
Iris Bloomer 《General Relativity and Gravitation》1978,9(9):763-771
A maximally symmetric space, i.e., homogeneous and isotropic at every point, possessing totally antisymmetric torsion is dealt with. It is found that maximum symmetry restricts the dimension of the space to three. The three-curvature tensor for the space is obtained and from its form a three-metric is then constructed. The three-space is then allowed to evolve in time so that a four-metric of the formds
2= –dt
2+ (3)g
ij
dx
i
dx
j
is possible. From this an equation of motion is obtained which predicts an initial- and final-state singularity.Part of this work was done as a doctoral thesis requirement at Queen Mary College, University of London. 相似文献
143.
Abazov VM Abbott B Abolins M Acharya BS Adams DL Adams M Adams T Agelou M Agram JL Ahmed SN Ahn SH Alexeev GD Alkhazov G Alton A Alverson G Alves GA Anderson S Andrieu B Arnoud Y Askew A Asman B Autermann C Avila C Babukhadia L Bacon TC Baden A Baffioni S Baldin B Balm PW Banerjee S Barberis E Bargassa P Baringer P Barnes C Barreto J Bartlett JF Bassler U Bauer D Bean A Beauceron S Beaudette F Begel M Beri SB Bernardi G Bertram I Besançon M Besson A Beuselinck R Bezzubov VA Bhat PC Bhatnagar V 《Physical review letters》2004,93(14):141801
A search for pair production of doubly charged Higgs bosons in the process pp -->H(++)H(--) -->mu(+)mu(+)mu(-)mu(-) is performed with the D0 run II detector at the Fermilab Tevatron. The analysis is based on a sample of inclusive dimuon data collected at an energy of sqrt[s]=1.96 TeV, corresponding to an integrated luminosity of 113 pb(-1). In the absence of a signal, 95% confidence level mass limits of M(H(+/-+/-)(L))>118.4 GeV/c(2) and M(H(+/-+/-)(R))>98.2 GeV/c(2) are set for left-handed and right-handed doubly charged Higgs bosons, respectively, assuming 100% branching into muon pairs. 相似文献
144.
Under the right conditions, bromine trifluoride can be a useful tool for generating new types of reactions and compounds. Thus, tris(methylthio)alkyl derivatives, easily prepared from the corresponding alkyl bromides, were converted to the corresponding RCHBrCF2SMe or RCHBrCF3 compounds. The bromine atom, however, could be easily reduced forming eventually R'CF2SMe or R'CF3. If desired, the bromine atom can serve as an entry for constructing terminal difluoroolefins. 相似文献
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149.
Reaction of Zn(NO3)2·6H2O with the bent bridging ligand 4,4′-dithiodipyridine (dtdp), showing axial chirality, in the presence of the chelating 1,10-phenanthroline
(phen) ligand in ethanol yielded [{Zn(μ-dtdp)2(H2O)2}(NO3)2·2C2H5OH·2H2O]
n
(1). In 1, Zn2+ ions are linked by two dtdp ligands of opposite chirality into a one-dimensional coordination polymer of the repeated-rhomboid
type; the phen co-ligand was not encountered in the crystal. Pseudo-symmetry of the lattice is discussed for 1. Reaction of Zn(NO3)2·6H2O and dtdp in an ethanol/water mixture in absence of phen led to the known repeated-rhomboid coordination polymer [{Zn(NO3)(μ-dtdp)2(H2O)}NO3·4H2O]
n
(2), the crystal structure of which was redetermined at 110 K. At low temperature, the nitrato-κO ligand in one axial position of Zn2+ was found to be non-disordered as distinct from the room temperature structure (Horikoshi and Mikuriya, Cryst Growth Des
5:223–230, 2005). The Zn2+ ions in 2 are joined by two dtdp ligands of the same chirality. 相似文献
150.
Dr. Yogesh Somasundar Iris C. Lu Dr. Matthew R. Mills Lisa Y. Qian Ximena Olivares Prof. Dr. Alexander D. Ryabov Prof. Dr. Terrence J. Collins 《Chemphyschem》2020,21(11):1083-1086
Understanding the catalysis of oxidative reactions by TAML activators of peroxides, i. e. iron(III) complexes of tetraamide macrocyclic ligands, advocated a spectrophotometric procedure for quantifying the catalytic activity of TAMLs for colorless targets (kII′, M−1 s−1), which is incomparably more advantageous in terms of time, cost, energy, and ecology than NMR, HPLC, UPLC, GC-MS and other similar techniques. Dyes Orange II or Safranin O (S) are catalytically bleached by non-excessive amount of H2O2 in the presence of colorless substrates (S1) according to the rate law: −d[S]/dt=kIkII[H2O2][S][TAML]/(kI[H2O2]+kII[S]+kII′[S1]). The bleaching rate is thus a descending hyperbolic function of S1 : v=ab/(b+[S1]). Values of kII′ found from a and b for phenol and propranolol with commonly used TAML [FeIII{o,o′-C6H4(NCONMe2CO)2CMe2}2(OH2)]+ are consistent with those for S1 (phenol, propranolol) obtained directly by UPLC. The study sends vital messages to enzymologists and environmentalists. 相似文献