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41.
Subhi A. Al-Jibori Afra S. S. Al-Zaubai Modher Y. Mohammed Talal A. K. Al-Allaf 《Transition Metal Chemistry》2007,32(3):281-286
Palladium(II) and platinum(II) complexes containing the mixed ligands tertiary diphosphines Ph2P(CH2)
n
PPh2, (n = 1–4) and benz-1,3-imidazoline-2-thione, benz-1,3-oxazoline-2-thione or benz-1,3-thiazoline-2-thione have been prepared
and characterized by elemental analysis, magnetic susceptibility, molar conductance and i.r. spectral data. 31P–{1H}-n.m.r. data have been applied to characterize the produced linkage isomers. 相似文献
42.
Ishida Y Madonna AJ Rees JC Meetani MA Voorhees KJ 《Rapid communications in mass spectrometry : RCM》2002,16(19):1877-1882
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), utilizing an on-probe sample pretreatment, was applied to the rapid and direct detection of intact phospholipids from whole bacterial cells. The sample preparation procedure involved depositing growing bacterial colonies from culture dishes directly onto the MALDI probe followed by treatment of the sample spot with a 3 micro L aliquot of an aqueous 0.05 M solution of sodium iodide prior to the addition of a 2,5-dihydroxybenzoic acid (DHB) matrix solution (ca. 8 mg dissolved in 70% acetonitrile/30% H(2)O containing 0.1% of trifluoroacetic acid). The MALDI spectra obtained from whole bacteria cells showed a series of ions generated from bacterial phospholipids, such as phosphatidylethanol-amines (PEs) and phosphatidylglycerols (PGs), which were clearly observed as well-resolved peaks. The ranges of the observed total carbon numbers in two acyl groups for PEs and PGs (30-36 and 33-36, respectively) were in good agreement with those reported previously. Furthermore, the distinct discrimination of four species of the Enterobacteriaceae family cultured identically was achieved by using principal components analysis (PCA) conducted on the relative peak intensities of phospholipids observed from the MALDI spectra. 相似文献
43.
Mohammed A. Bari Siddiqui Shakeel Ahmed Musaed S. Al-Gharami Chistopher F. Dean 《Reaction Kinetics and Catalysis Letters》2007,91(1):61-67
Sulfur reduction ability of alumina supported zinc, gallium and zinc-gallium additives for fluid catalytic cracking catalysts
was evaluated in a micro-activity test unit (MAT). Gallium/alumina showed the highest sulfur reduction of 31%, but the cracking
activity of the catalyst was decreased. Zinc-gallium/alumina reduced sulfur in 24 wt.% without decreasing the base catalyst
activity. 相似文献
44.
Mohammed R. Arshadi 《Journal of mass spectrometry : JMS》1978,13(7):379-381
The 70 eV positive and negative ion mass spectra of the oxygen, sulphur and selenium 2,1,3-benzodiazoles have been studied. The influence of hetero atom on the fragmentation modes of the benzodiazole molecular ions has been discussed. 相似文献
45.
Fettouhi M Ouahab L Boukhari A Cador O Mathonière C Kahn O 《Inorganic chemistry》1996,35(17):4932-4937
The goal of this work was to synthesize new molecular bricks which could be used as precursors of heterobimetallic low-dimensional compounds. Along this line, four compounds have been synthesized and structurally characterized, namely (NBu(4))(2)[Ni(Cl(2)opba)] (1), (NBu(4))(2)[Cu(Cl(2)opba)] (2), (NBu(4))(5)[Mn(Cl(2)opba)(DMSO)(2)](4) (3), and Cu(en)(2)[Mn(Cl(2)opba)(H(2)O)(2)](2).2DMSO (4), with Cl(2)opba = (4,5-dichloro-o-phenylene)bis(oxamato), NBu(4) = tetra-n-butylammonium, en = ethylenediamine, and DMSO = dimethyl sulfoxide. Compounds 1 and 2 are isostructural; they crystallize in the monoclinic system, space group C2/c, Z = 4, with a = 18.708(2) ?, b = 17.525(2) ?, c = 14.763(9) ?, and beta = 92.03(4) degrees for 1 and a = 18.928(2) ?, b = 17.634(2) ?, c = 14.704(9) ?, and beta = 92.38(3) degrees for 2. 3 crystallizes in the tetragonal system, space group P&fourmacr;2(1)c, Z = 2, with a = 26.295(10) ? and c = 12.342(7) ?. The structure shows a random occupation of the metal site by Mn(III) and Mn(II) ions in 3/4 and 1/4 ratios, respectively. 4 crystallizes in the triclinic system, space group P&onemacr;, Z = 1, with a = 7.066(7) ?, b = 11.844(1) ?, c = 14.292(5) ?, alpha = 105.64(2) degrees, beta = 97.67(5) degrees, and gamma = 102.13(3) degrees. The structure consists of Mn(III)Cu(II)Mn(III) trinuclear species, with Cu-O-Mn bridges involving oxygen atoms of the oxamato groups already linked to the metal atom. The magnetic properties of compounds 1-4 have been investigated and quantitatively interpreted. For 3, this magnetic investigation has been performed on a single crystal, which allows us to determine unambiguously the sign of the axial zero-field splitting parameter for the Mn(III) ion. The potentialities of these new molecular bricks have been discussed. 相似文献
46.
Khalid Mohammed Khan Ghulam Murtaza MaharviSafdar Hayat Zia-UllahM. Iqbal Choudhary Atta-ur-Rahman 《Tetrahedron》2003,59(29):5549-5554
Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters. 相似文献
47.
Farida Larit Khaled M. Elokely Manal A. Nael Samira Benyahia Francisco Len Stephen J. Cutler Mohammed M. Ghoneim 《Molecules (Basel, Switzerland)》2021,26(4)
The in vitro activity of L. donovani (promastigotes, axenic amastigotes and intracellular amastigotes in THP1 cells) and T. brucei, from the fractions obtained from the hydroalcoholic extract of the aerial part of Hypericum afrum and the isolated compounds, has been evaluated. The chloroform, ethyl acetate and n-butanol extracts showed significant antitrypanosomal activity towards T. brucei, with IC50 values of 12.35, 13.53 and 12.93 µg/mL and with IC90 values of 14.94, 19.31 and 18.67 µg/mL, respectively. The phytochemical investigation of the fractions led to the isolation and identification of quercetin (1), myricitrin (2), biapigenin (3), myricetin (4), hyperoside (5), myricetin-3-O-β-d-galactopyranoside (6) and myricetin-3’-O-β-d-glucopyranoside (7). Myricetin-3’-O-β-d-glucopyranoside (7) has been isolated for the first time from this genus. The chemical structures were elucidated by using comprehensive one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopic data, as well as high-resolution electrospray ionization mass spectrometry (HR-ESI–MS). These compounds have also been evaluated for their antiprotozoal activity. Quercetin (1) and myricetin (4) showed noteworthy activity against T. brucei, with IC50 and IC90 values of 7.52 and 5.71 µM, and 9.76 and 7.97 µM, respectively. The T. brucei hexokinase (TbHK1) enzyme was further explored as a potential target of quercetin and myricetin, using molecular modeling studies. This proposed mechanism assists in the exploration of new candidates for novel antitrypanosomal drugs. 相似文献
48.
Bikrani Mohammed Fidalgo M. Luz Garralda María A. Ibarlucea Lourdes 《Transition Metal Chemistry》1999,24(4):394-397
-Diimines, RN:C(R)C(R):NR(LL) derived from glyoxal, GLL (R=H) abbreviated as GAA (R= R=4-dimethylaminophenyl) or GHA (R= R=4-hydroxyphenyl), and derived from biacetyl, BLL (R=Me) abbreviated as BDH (R=R= NH2), BOH (R=NH2, R=OH) react with carbonylrhodium(I) compounds to give different products depending on the imino substituents in the ligand and/or the solvent employed. The reaction of -diimines bearing amino groups, such as GAA or BDH with [RhCl(CO)2]2 in acetone yields binuclear [RhCl(CO)2]2(-LL) while in CH2Cl2 ionic [Rh- (CO)2(LL)]+[RhCl2(CO)2]– species are obtained. In acetone [RhCl(CO)2]2(-GAA) exists as an equilibrium mixture between two different neutral binuclear species; [Rh(CO)2(BDH)]+ exists as a mixture of two species containing chelate or monodentate bonded diimine respectively. GAA or BDH react in situ with [RhCl(CO)(C2H4)]2 in benzene to yield tetracoordinated monocarbonylated [RhCl(CO)(LL)] compounds. -Diimines (LL) bearing hydroxy groups, such as GHA or BOH react with [RhCl(CO)2]2 or [RhCl(CO)(C2H4)]2 to give pentacoordinated dicarbonylated [RhCl(CO)2(LL)] compounds. 相似文献
49.
Formation of PdNiZn thin film at oil‐water interface: XPS study and application as Suzuki‐Miyaura catalyst 下载免费PDF全文
Nanosheet of PdNiZn and nanosphere of PdNiZn/reduced‐graphene oxide (RGO) with sub‐3 nm spheres have been successfully synthesized through a facile oil‐water interfacial strategy. The morphology and composition of the films were determined by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive analysis of X‐ray (EDAX) and elemental mapping. In the present study, we have developed a method to minimize the usage of precious Pd element. Due to the special structure and intermetallic synergies, the PdNiZn and PdNiZn/RGO nanoalloys exhibited enhanced catalytic activity and durability relative to Pd nanoparticles in Suzuki‐Miyaura C‐C cross‐coupling reaction. Compared to classical cross‐coupling reactions, this method has the advantages of a green solvent, short reaction times, low catalyst loading, high yields and reusability of the catalysts. 相似文献
50.
In this paper, we establish the existence of multiple solutions for nonhomogeneous singular elliptic equations with cylindrical weights, by using Ekeland??s variational principle and mountain pass theorem without Palais?CSmale condition. 相似文献