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51.
Fe(BF(4))(2)·6H(2)O with pyridine-2,6-dicarboxylic acid and PhIO can efficiently catalyze the regioselective oxidation of terminal alkene derivatives to aldehydes under mild and benign reaction conditions. 相似文献
52.
V.K. Sharma S. Mitra P. Maheshwari D. Dutta P.K. Pujari R. Mukhopadhyay 《The European physical journal. Special topics》2010,189(1):273-277
Dynamics of ethylene glycol (EG) adsorbed in H-ZSM5 zeolite as studied using quasielastic neutron scattering (QENS) technique is reported here. Analysis of QENS data revealed that observed dynamics correspond to isotropic rotational motion of EG. Rotational diffusion coefficient of EG adsorbed in H-ZSM5 zeolite is found to be slower compared to bulk and comparable to that of benzene adsorbed in the same host. Positron Annihilation Spectroscopy (PAS) technique is used to understand the nature of guest-host interaction and the results of both QENS and PAS are found to be consistent with each other. 相似文献
53.
Chandra S Sangeetika Sharma SD 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(4):755-760
The hydroxo-bridge complexes of the type [Fe(2)(ligand-H)(4)(OH)(2)] with bidentate nitrogen-oxygen donor ligands, viz. 2-hydroxynaphthaldehydeoxime [hnoH(2)], 2-hydroxyacetphenoneoxime [haoH(2)], salicylaldooxime [SalH(2)], 2-hydroxypropiophenoneoxime [hnoH(2)] have been prepared. All the complexes have been characterized by elemental analysis, magnetic moments, electronic and M?ssbauer spectral studies. M?ssbauer parameters of the complexes clearly suggest high spin configuration of Fe(III) showing lower magnetic moment to that of the spin only value, i.e. 5.92 BM. It may be due to the antiferromagnetic interaction between Fe(III) centers. 相似文献
54.
Lee CM Hsieh CH Dutta A Lee GH Liaw WF 《Journal of the American Chemical Society》2003,125(38):11492-11493
Iron-nitrosyl complex containing S-bonded monosulfinate [PPN][(NO)Fe(S,SO2-C6H4)(S,S-C6H4)] (3) has been isolated from sulfur oxygenation of complex [PPN][(NO)Fe(S,S-C6H4)2] (2) which is obtained from addition of NO molecule to [PPN][(C4H8O)Fe(S,S-C6H4)2] (1) in organic solvents. This result reveals that binding of NO to the iron center promotes sulfur oxygenation of iron dithiolates by dioxygen and stabilizes the S-bonded sulfinate iron species. Analysis of the bond angles for complexes 2 and 3 reveals that iron is best described as existing in a distorted trigonal bipyramidal coordination environment surrounded by one NO, three thiolates, and one sulfinate in complex 3, whereas the distorted square pyramidal geometry is adopted in complex 2. Complex 3 further reacts in organic solvents with molecular oxygen in the presence of [PPN][NO2] to produce the dinuclear bis(sulfinate) complex [PPN]2[(NO)Fe(SO2,SO2-C6H4)(S,S-C6H4)]2 (4). Complex 3 showed reaction with PPh3 in THF/CH2Cl2 to yield complex 2 and Ph3PO. Upon photolysis of CH2Cl2 solution of complex 3 under N2 purge at ambient temperature, the UV-vis and IR spectra consistent with the formation of complex 2 demonstrate that complex 2 and 3 are photochemically interconvertible. Obviously, complex 3 is thermally quite stable but is photochemically active toward [O] release. Also described are the X-ray crystal structures of 3 and 4. 相似文献
55.
Ambarish Mondal Rajat K. Tripathy Parul Dutta Manas Kumar Santra Anvarhusein A. Isab Christopher W. Bielawski Hemanta K. Kisan Swapan K. Chandra Joydev Dinda 《应用有机金属化学》2019,33(1)
The syntheses, structures, and chemotherapeutic activities of Ag(I)‐, Au(I)‐, and Ru(II)‐complexes ligated to a novel N‐heterocyclic carbene ligand, 2‐(4‐nitrophenyl)imidazo[1,5‐a]pyridin‐2‐ylidene ( 1 ), are described. The corresponding complexes, [Ag( 1 )2][PF6], [Au( 1 )2][PF6] ( 3 ), and [Ru( 1 )(p‐cymene)Cl][PF6] ( 4 ), were prepared using convenient transmetallation chemistry and characterized using a range of spectroscopic and analytical techniques. X‐ray crystallography revealed that complexes 2 and 3 adopted linear structures whereas 4 exhibited a prototypical “piano‐stool”‐like geometry; the structural assignments were further supported by DFT calculations. A series of in vitro studies revealed that while the aforementioned Ag(I), Au(I) and Ru(II) complexes exhibited significant cytotoxicities against the human colon adenocarcinoma (HCT 116), lung cancer (A549), and breast cancer (MCF7) cell lines, the Ru derivative was most prominent. 相似文献
56.
Soma Bahmany Lucia E.A. de Wit Dennis A. Hesselink Teun van Gelder Nauras M. Shuker Carla Baan Bart C.H. van der Nagel Birgit C.P. Koch Brenda C.M. de Winter 《Biomedical chromatography : BMC》2019,33(1)
After solid organ transplantation, tacrolimus is given to prevent rejection. Therapeutic drug monitoring is used to reach target concentrations of tacrolimus in whole blood. Because the site of action of tacrolimus is the lymphocyte, and tacrolimus binds ~80% to erythrocytes, the intracellular tacrolimus concentration in lymphocytes is possibly more relevant. For this purpose, we aimed to develop, improve and validate a UPLC–MS/MS method to measure tacrolimus concentrations in isolated peripheral blood mononuclear cells (PBMCs). PBMCs were isolated using a Ficoll separation technique, followed by a washing step using red blood cell lysis. A cell suspension of 50 μL containing 1 million PBMCs was used in combination with MagSiMUS‐TDMPREP. To each sample we added 30 μL lysis buffer, 20 μL reconstitution buffer containing 13C2H4‐tacrolimus as internal standard, 40 μL MagSiMUS‐TDMPREP Type I Particle Mix and 175 μL Organic Precipitation Reagent VI for methanol‐based protein precipitation. A 10 μL aliquot of the supernatant was injected into the UPLC–MS/MS system. The method was validated, resulting in high sensitivity and specificity. The method was linear (r2 = 0.997) over the range 5.0–1250 pg/1 × 106 PBMCs. The inaccuracy was <5% and the imprecision was <15%. The washing steps following Ficoll isolation could be performed at either room temperature or on ice, with no effect of the temperature on the results. A method for the analysis of tacrolimus concentrations in PBMCs was developed and successfully validated. Further research will be performed to investigate the correlation between concentrations in PBMCs and clinical outcome. 相似文献
57.
Shubham Dutta Rajendra K. Mallick Rangu Prasad Vincent Gandon Akhila K. Sahoo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2311-2316
Ynamides are typically more reactive than simple alkynes and olefins. However, a serendipitous observation revealed a rare case where the reactivity of simple alkynes exceeds that of ynamides. This led to the development of a unique sulfur‐radical‐triggered cyclization of yne‐tethered ynamides, which involves attack of the alkyne by a thiyl radical followed by cyclization with the ynamide. A wide range of novel 4‐thioaryl pyrroles that could tolerate common functional moieties and N‐protecting groups were expediently constructed by this strategy. The current method contrasts with the typical cyclization of yne‐ynamides, which involves the attack of the alkyne moiety by the ynamide core. Control experiments and DFT calculations supported the participation of the sulfur radical in the reaction and the regioselective cyclization. The synthetic potential of the substituted pyrroles is also discussed. 相似文献
58.
Banerjee K Dasgupta S Jadhav MR Naik DG Ligon AP Oulkar DP Savant RH Adsule PG 《Journal of AOAC International》2010,93(6):1957-1964
An analytical method is reported for residue analysis of the fungicide meptyldinocap in different fruit matrixes that involves extraction with ethyl acetate, hydrolysis of the residues with ethanolamine, and determination by LC/MS/MS. The method involves extraction of 10 g sample with 10 mL ethyl acetate; evaporation of the ethyl acetate phase to dryness, and subsequent hydrolysis of the residues to 4,6-dinitro-2-(1-methylheptyl) phenol on reaction with 1% ethanolamine. The pH of this hydrolyzed product was neutralized with formic acid and analyzed by LC/MS/MS. The hydrolysis reaction followed pseudo-first-order kinetics, and the reaction product was spectroscopically confirmed as 2-(1-methylheptyl)-4,6-dinitrophenol. The method offered > 80% recoveries at an LOQ of 10 ng/g for grape and mango, 25 ng/g for pomegranate with intralaboratory Horwitz ratio < 0.5, and measurement uncertainties < 10% at LOQ levels. Considering first-order rate kinetics, activation energy, enthalpy of activation, and entropy of activation varied as solvent > mango > grape > pomegranate. Free energy of activation at 298 K was higher than at 280 K and was similar for solvent and three matrixes at both temperatures. 相似文献
59.
Kaushik Chanda Milan Ch. Dutta Enamul Karim Jai N. Vishwakarma 《Journal of heterocyclic chemistry》2004,41(4):627-631
1‐(Aralkyl/aryl)‐3‐(alkyyaralkyl)‐5‐aroyl‐1,2,3,4‐tetrahydropyrimidines ( 2a‐c ) have been synthesized by dethiomethylation of 5‐aroyl‐6‐methylthio‐1,2,3,4‐tetrahydropyrimidines ( 1a‐c ). An alternative one‐pot synthetic strategy has been developed for the title compounds 2a‐t by the reaction of enaminones 3 with pri mary amine and formaldehyde in refluxing methanol in good yields. 相似文献
60.
The Hexagallane [Ga6{SiMe(SiMe3)2}6] and the closo‐Hexagallanate [Ga6{Si(CMe3)3}4 (CH2C6H5)2]2— — the Transition to an Unusual precloso‐Cluster The closo hexagallanate [Ga6R4(CH2Ph)2]2— (R = SitBu3) as well as the hexagallane Ga6R6 (R = SiMe(SiMe3)2) with only six cluster electron pairs were isolated from reactions of “GaI” with the corresponding silanides. The structure of the latter is derived from an octahedron by a Jahn‐Teller‐distortion and is different from the capped trigonal bipyramidal one expected by the Wade‐Mingos rules. Both compounds were characterized by X‐ray crystallography. The bonding is discussed with simplified Ga6H6 and Ga6H62— models via DFT methods. 相似文献