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1
Armstrong, David R., Liam Balloch, Eva Hevia, Alan R. Kennedy, Robert E. Mulvey, Charles T. O'Hara y Stuart D. Robertson. "Meta-metallation of N,N-dimethylaniline: Contrasting direct sodium-mediated zincation with indirect sodiation-dialkylzinc co-complexation". Beilstein Journal of Organic Chemistry 7 (6 de septiembre de 2011): 1234–48. http://dx.doi.org/10.3762/bjoc.7.144.
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Previously we reported that direct zincation of N,N-dimethylaniline by the mixed-metal zincate reagent 1 ((TMEDA)Na(TMP)(t-Bu)Zn(t-Bu)) surprisingly led to meta-metallation (zincation) of the aniline, as manifested in the crystalline complex 2 ((TMEDA)Na(TMP)(m-C6H4-NMe2)Zn(t-Bu)), and that iodination of these isolated crystals produced the meta-isomer N,N-dimethyl-3-iodoaniline quantitatively. Completing the study here we find that treating the reaction solution with iodine produces a 72% conversion and results in a mixture of regioisomers of N,N-dimethyliodoaniline, with the meta-isomer still the major product (ortho:meta:para ratio, 6:73:21), as determined by NMR. In contrast to this bimetallic method, sodiation of N,N-dimethylaniline with n-BuNa produced the dimeric, ortho-sodiated complex 3 (((TMEDA)Na(o-C6H4-NMe2))2), as characterised by X-ray crystallography and NMR. No regioisomers were observed in the reaction solution. Introducing t-Bu2Zn to this reaction solution afforded a cocrystalline product in the solid-state, composed of the bis-anilide 4 ((TMEDA)Na(o-C6H4-NMe2)2Zn(t-Bu)) and the Me2N–C cleavage product 5 ({(TMEDA)2Na}+{(t-Bu2Zn)2(µ-NMe2)}−), which was characterised by X-ray crystallography. NMR studies of the reaction mixture that produces 4 and 5 revealed one additional species, but the mixture as a whole contained only ortho-species and a trace amount of para-species as established by iodine quenching. In an indirect variation of the bimetallic reaction, TMP(H) was added at room temperature to the reaction mixture that afforded 4 and 5. This gave the crystalline product 6 ((TMEDA)Na(TMP)(o-C6H4-NMe2)Zn(t-Bu)), the ortho-isomer of the meta-complex 2, as determined from X-ray crystallographic and NMR data. Monitoring the regioselectivity of the reaction by iodination revealed a 16.6:1.6:1.0 ortho:meta:para ratio. Interestingly, when the TMP(H) containing solution was heated under reflux for 18 hours more meta-isomer was produced (corresponding ratio 3.7:4.2:1.0). It is likely that this change has its origin in a retro reaction that produces the original base 1 as an intermediate. Theoretical calculations at the DFT level using the B3LYP method and the 6-311G** basis set were used to probe the energetics of both monometallic and bimetallic systems. In accord with the experimental results, it was found that ortho-metallation was favoured by sodiation; whereas meta- (closely followed by para-) metallation was favoured by direct sodium-mediated zincation.
2
Fishbein, James C. y Robert A. McClelland. "Halide ion trapping of nitrenium ions formed in the Bamberger rearrangement of N-arylhydroxylamines. Lifetime of the parent phenylnitrenium ion in water". Canadian Journal of Chemistry 74, n.º 7 (1 de julio de 1996): 1321–28. http://dx.doi.org/10.1139/v96-147.
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The acid reactions of five arylhydroxylamines (Ar = 2,6-Me2C6H3, 2,5-Me2C6H3, 2-MeC6H4, 2-ClC6H4, and C6H5) have been studied at constant ionic strength (NaClO4) in the presence of varying amounts of NaBr and NaCl. Each system resulted in the corresponding p-aminophenol, the product of Bamberger rearrangement, as the only detectable product in the absence of halide. The addition of halide ion reduced the yield of this product, with the appearance of the corresponding p-haloaniline, o-haloaniline (where appropriate), and the parent aniline (predominantly with bromide). Rate constants for the reaction were measured in the case of the parent and 2,6-dimethyl systems and showed small decreases (chloride) or increases (bromide) with increasing halide concentration. These changes did not correlate with the change in products, implying that the rate variations were caused by specific salt effects. Product data were analyzed by a mechanism involving rate-limiting formation of the appropriate arylnitrenium ion followed by product-determining steps involving trapping by the solvent or by the added halide. The possibility that a portion of the halide-trapped products were derived from a pre-association mechanism was also included. Kinetic analyses then produced kBr:kw and kCl:kw ratios for two limiting cases, one involving pre-association with an equilibrium constant kas = 0.3, and one ignoring pre-association. From an azide:water ratio (kAz:kw) previously determined for the 2,6-dimethylphenylnitrenium, kBr was concluded to lie in the range (4–5) × 109 M−1 s−1 for all of the nitrenium ions of this study. This range for kBr then led to kw values of (1–2) × 109 s−1 (2,5-Me2), (2–3) × 109 s−1 (2-Me), and (4–8) × 109 s−1 (parent and 2-Cl), where the ranges reflect uncertainties in the exact value of kBr and in the contribution from pre-association. The lifetime of the parent phenylnitrenium ion in water at one molar ionic strength is concluded to lie in the range 125–250 ps. Key words: nitrenium ion lifetime, phenylhydroxylamine, phenylnitrenium ion, Bamberger rearrangement.
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Mungmeechai, T., Suesat Jantip y P. Suwanruji. "Study of the Relationships between the Chemical Structures of Azo Disperse Dyes and their Dyeing Properties on Polyester". Advanced Materials Research 93-94 (enero de 2010): 332–35. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.332.
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A series of azo disperse dyes was synthesized using 4-nitro aniline and 2-chloro-4-nitro aniline as diazo components. The coupling components were N,N-diethyl aniline, N,N-bis-β-hydroxyethyl aniline, N,N-bis-β-acetoxyethyl aniline, N,N-diethyl-m-toluidine, N,N-bis-β-hydroxyethyl-m-toluidine and N,N-bis-β-acetoxyethyl-m-toluidine. The structures of the synthesized dyes were confirmed by TLC, 1H NMR and elemental analysis. The spectroscopic properties of the dyes when dissolved in the organic solvents viz. ethyl acetate and methyl benzoate, were investigated. The absorption spectra of the dyes showed a bathochromic shift when the polarity of the solvents increased. In addition, the substituent groups on the dye structures influenced the spectroscopic properties of the dyes. The dyeing properties of the dyes on poly(ethylene terephthalate) and poly(lactic acid) fabrics were also studied. The dyes exhibited a slight difference in shade on the two polyester fabrics. Heat and light fastness properties of the dyed fabrics were also examined.
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Ajeetha, N. y V. G. K. M. Pisipati. "The Influence of the Position of Oxygen on the Phase Behaviour of Benzylidene Anilines". Zeitschrift für Naturforschung A 58, n.º 12 (1 de diciembre de 2003): 735–37. http://dx.doi.org/10.1515/zna-2003-1209.
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Synthesis and Characterization of N (p-n-alkyl benzylidene)-p-n-alkoxy anilines (n.Om), N (p-nalkoxy benzylidene)-p-n-alkoxy anilines (nO.Om) and N (p-n-alkyl benzylidene)-p-n-alkyl anilines (n.m), where n = m = either 4 or 5, has been carried out using thermal microscopy (TM) and differential scanning calorimetry (DSC). The results are discussed in the light of other experimental observations on N (p-n-alkoxy benzylidene)-p-n alkyl anilines (nO.m). It has been observed that the position of oxygen on either side of the rigid core of the benzylidene moiety plays an important role in the manifestation of different phase variants.
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Ryan, David A., Jeremy K. M. Sanders, Gerald C. Curtis y Helen Hughes. "NMR study of whole rat bile: the biliary excretion of 4-cyano-N,N-dimethyl aniline by an isolated perfused rat liver and a liver in situ". Journal of Pharmaceutical and Biomedical Analysis 13, n.º 6 (enero de 1995): 735–45. http://dx.doi.org/10.1016/0731-7085(95)01265-m.
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Morar, Cristina, Pedro Lameiras, Attila Bende, Gabriel Katona, Emese Gál y Mircea Darabantu. "Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit". Beilstein Journal of Organic Chemistry 14 (9 de julio de 2018): 1704–22. http://dx.doi.org/10.3762/bjoc.14.145.
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Background: 4-(n-Octyloxy)aniline is a known component in the elaboration of organic materials with mesogenic properties such as N-substituted Schiff bases, perylene bisimide assemblies with a number of 2-amino-4,6-bis[4-(n-octyloxy)phenylamino]-s-triazines, amphiphilic azobenzene-containing linear-dendritic block copolymers and G-0 monomeric or dimeric dendritic liquid crystals with photochromic azobenzene mesogens. The present ab initio study explores a previously unknown use of 4-(n-octyloxy)aniline in the synthesis, structure and supramolecular behaviour of new dendritic melamines. Results: Starting from 4-(n-octyloxy)aniline, seven G-2 melamine-based dendrimers were obtained in 29–79% overall yields. Their iterative convergent- and chemoselective synthesis consisted of SN2-Ar aminations of cyanuric chloride and final triple N-acylations and Williamson etherifications (→ G-2 covalent trimers) or stoichiometric carboxyl/amino 1:3 neutralisations (→ G-2 ionic trimers). These transformations connected G-1 chloro- and amino-termini dendrons to m-trivalent cores (triazin-2,4,6-triyl and benzene-1,3,5-triyl units) or tripodands (central building blocks), such as N-substituted melamines with 4-hydroxyphenyl or phenyl-4-oxyalkanoic motifs. Owing to the diversity of cores and central building blocks, the structural assortment of the dendritic series was disclosed by solvation effects (affecting reactivity), rotational stereodynamism and self-organisation phenomena (determining a vaulted and/or propeller macromolecular shape in solution). DFT calculations (in solution), (VT) NMR and IR (KBr) spectroscopy supported these assignments. TEM analysis revealed the ability of the title compounds towards self-assembling into homogeneously packed spherical nano-aggregates. Conclusions: The (non)covalent synthesis and step-by-step structural elucidation of novel G-2 melamine dendrimers based on 4-(n-octyloxy)aniline are reported. Our study demonstrates the crucial influence of the nature (covalent vs ionic) of the dendritic construction in tandem with that of its central building blocks on the aptitude of dendrimers to self-organise in solution and to self-assembly in the solid state.
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Holman, Michelle A., Natalie M. Williamson y A. David Ward. "Preparation and Cyclization of Some N-(2,2-Dimethylpropargyl) Homo- and Heteroaromatic Amines and the Synthesis of Some Pyrido[2,3-d]pyrimidines". Australian Journal of Chemistry 58, n.º 5 (2005): 368. http://dx.doi.org/10.1071/ch04260.
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The Cu(i) catalyzed cyclization of o-substituted N-(2,2-dimethylpropargyl)anilines yields 8-substituted 2,2-dimethyl-1,2-dihydroquinolines, while m-substituted analogues provide a mixture of 5- and 7-substituted dihydroquinoline systems. This reaction can be extended to 2-amino-N-(2,2-dimethylpropargyl)anthracene, yielding a dihydronaphtho[2,3-f]quinoline product, and to aminoquinoline derivatives, which yield substituted phenanthroline products. Pyridine analogues did not cyclize, apparently because of complexation with the copper reagent. An alternative synthetic approach to these cyclized products, when complexation may be a problem, is illustrated by the following example. 2-Chloro-4-N-(2,2-dimethylpropargyl)pyrimidine was reduced using a Lindlar catalyst to the corresponding alkene which did not undergo an amino-Claisen rearrangement. However, the 5-bromopyrimidine alkene analogue underwent addition with phenylselanyl bromide to give a product that cyclized, using butyllithium, to a pyrido[2,3-d]pyrimidine selenium-containing product from which the selenium moiety could be removed to yield either a dihydro- or a tetrahydro-pyrido[2,3-d]pyrimidine system. A Heck reaction on the 5-bromopyrimidine alkene gave a 5-methylene-6,7-dihydro-5H-pyrrolo[2,3-d]pyrimidine.
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Mikrovannidis, J. A. "Synthesis and characterization of polycarbonates derived from N,N′-m-phenylenebis(3-hydroxybenzamide) and 4,4-bis(4-hydroxyphenyl)pentanoic acid anilide". European Polymer Journal 21, n.º 12 (enero de 1985): 1031–34. http://dx.doi.org/10.1016/0014-3057(85)90209-5.
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Pisipati, Venkata, M. Saraswathi, D. Madhavi Latha, P. Pardhasaradhi y P. V. Datta Prasad. "Synthesis, Characterization and Phase Transition Studies on Some N-(4-Butyloxy Benzylidene)-4-Alkoxy Anilines, 4O.Om Compounds - A Dilatometric Study". JOURNAL OF ADVANCES IN PHYSICS 2, n.º 1 (5 de octubre de 2013): 38–47. http://dx.doi.org/10.24297/jap.v2i1.2101.
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Dilatometric studies are carried out on the synthesized N-(4-butyloxy benzylidene)-4-alkoxy anilines, 4O.Om compounds with the m = 3 to 7 and 9. Characterization of these compounds is done using the polarizing microscope attached with a hot stage. The differential scanning calorimeter is employed to find out the transition temperatures as well as the heats of transitions. All the compounds exhibit nematic phase with varying thermal ranges with the clearing temperatures are above 100 OC as unlike the case of the well known N-(4-butyloxy benzylidene)-4-alkyl anilines, 4O.m compounds which exhibit rich poymorphysim and the clearing temperatures are well below 100 OC. As expected the isotropic to nematic transition exhibited first order nature and the results are discussed with the body of the data available in literature.
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Zhou, Ting-Ting, Dong-Mei Zhang, Jia-Wen Li y Fan Zhang. "Crystal structure of dichlorido(2-(1-methyl-1H-benzo[d]imidazol-2-yl)aniline-κ2N,N′)zinc(II)". Zeitschrift für Kristallographie - New Crystal Structures 231, n.º 2 (1 de junio de 2016): 477–78. http://dx.doi.org/10.1515/ncrs-2015-0146.
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Macías, M. A., J. A. Henao, Lina María Acosta y Alirio Palma. "Synthesis and X-ray powder diffraction data of 7-fluoro-2-exo-(2-methylpropen-1-yl)-2,3,4,5-tetrahydro-1,4-epoxybenzo[b]azepine". Powder Diffraction 28, n.º 1 (marzo de 2013): 49–52. http://dx.doi.org/10.1017/s0885715612000966.
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The stereoselective synthesis of 7-fluoro-2-exo-(2-methylpropen-1-yl)-2,3,4,5-tetrahydro-1,4-epoxybenzo[b]azepine was developed by intramolecular 1,3-dipolar cycloaddition of the nitrone derived from the corresponding 2-allyl-4-fluoro-N-(3-methylbut-2-enyl)aniline. The X-ray powder diffraction (XRPD) pattern for the new compound was analyzed and found to crystallize in a monoclinic system with space group P21/m (No. 11) and refined unit-cell parameters a = 11.655(5) Å, b = 5.850(2) Å, c = 18.314(4) Å, β = 104.27(3) and V = 1210.1 (6) Å3.
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Köster, Roland, Günter Seidel, Dieter Bläser y Roland Boese. "Dimere 9-Hydrochalkogeno-9-BBN-Verbindungen - Bildung und Kristallstruktur [1] / Dimeric Hydrochalcogeno-9-BBN Compounds - Formation and Crystal Structure [1]". Zeitschrift für Naturforschung B 49, n.º 3 (1 de marzo de 1994): 377–82. http://dx.doi.org/10.1515/znb-1994-0316.
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Abstract The trans-dimer of (9-HS-9-BBN)2 (1)2, obtained from H2S with (9H-9-BBN)2 or with (9-BBN)2S, crystallizes in the monoclinic space group C2/m [lattice constants (at 120 K): a = 15.279(2), b = 15.909(3), c = 6.822(4) Å; β = 91.05(4)°] with a planar B2S2ring. The cis-dimer of (9-HSe-9-BBN)2 (2)2, obtained from (9-BBN)2Se with aniline, crystallizes in the monoclinic space group P21/n [lattice constants (at 225 K): a = 6.892(1), b= 20.623(3), c = 12.226(2) Å; β = 97.28°] with an folded B2Se2ring.
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Zalov, Ali Z. y Kiril Blazhev Gavazov. "LIQUID-LIQUID EXTRACTION-SPECTROPHOTOMETRIC DETERMINATION OF MOLYBDENUM USING o-HYDROXYTHIOPHENOLS". JOURNAL OF ADVANCES IN CHEMISTRY 10, n.º 8 (24 de abril de 2017): 3003–11. http://dx.doi.org/10.24297/jac.v10i8.6687.
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27 liquid-liquid extraction-chromogenic systems containing Mo(VI), o-hydroxythiophenol derivative {HTPDs: 2-hydroxy-5-chlorothiophenol (HCTP), 2-hydroxy-5-bromothiophenol (HBTP) or 2-hydroxy-5-iodothiophenol (HITP)} and aromatic amine (AA) were studied. Aniline (An), N-methylaniline (mAn), N,N-dimethylaniline (dAn), o-toluidine (o-Tol), m-toluidine (m-Tol), p-toluidine (p-Tol), 3,4-xylidine (o-Xyl), 2,4-xylidine (m-Xyl), and 2,5-xylidine (p-Xyl) were the examined AAs. Optimization experiments for molybdenum extraction-spectrophotometric determination were performed and the following parameters were found for each of the systems: organic solvent (opt), pH (opt), CHTPD (opt), CAA (opt), shaking time (opt), l (max) and e (max). Under the optimum conditions, the molar ratio of the reacting Mo(V), HTPD and AA was 1:2:2 and the degrees of Mo extraction were R³98.4%. Linear relationships involving the spectral characteristics of the extracted complexes (lmax or emax) and some fundamental properties of the halogen substituent in the HTPD were discussed. The effect of foreign ions was examined and two sensitive, selective and precise procedures for extraction-spectrophotometric determination of molybdenum were proposed. The relative standard deviations for Mo content of (3-5)´10–4 mass % were 4% (HCTP-An procedure) and 3% (HBTP-An procedure).
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Satomura, S., Y. Miki, T. Hamanaka y Y. Sakata. "Kinetic assay of gamma-glutamyltransferase with use of bilirubin oxidase as a coupled enzyme." Clinical Chemistry 31, n.º 8 (1 de agosto de 1985): 1380–83. http://dx.doi.org/10.1093/clinchem/31.8.1380.
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Abstract We studied the kinetic measurement of gamma-glutamyltransferase (EC.2.3.2.2), coupling the reaction with that catalyzed by bilirubin oxidase (EC 1.3.3.5), which oxidizes and combines a phenylenediamine derivative with an aniline derivative to produce a green pigment. We measured the formation of the pigment kinetically (at lambda max745 nm, epsilon = 75 000 L mol-1 cm-1), with L-gamma-glutamyl-N-hydroxyethylaminoanilide as substrate and N-ethyl-N-hydroxy-3-sulfopropyl)-m-toluidine as a the coupling derivative. The within-run CV for measuring this reaction in samples of normal sera was 2.4%. A calibration plot of the change in absorbance per minute vs enzyme activity concentration showed good proportionality in the range of 0-1300 U/L. The results of this assay correlated well (r = 0.995) with those of the Boehringer method, in which L-gamma-glutamyl-3-carboxy-4-nitroanilide is the substrate. This new, highly sensitive procedure may be adapted to other assays involving phenylenediamine derivates as synthetic substrates.
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Chakravarthy, M. P., Dr K. N. Mohana y C. B. Pradeep Kumar. "The Inhibition of Mild Steel Corrosion in Sulfuric Acid by New Dapsone Derivatives". JOURNAL OF ADVANCES IN CHEMISTRY 10, n.º 3 (4 de abril de 2014): 2388–402. http://dx.doi.org/10.24297/jac.v10i3.2289.
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Dapsone derivatives Viz., 4, 4’-sulfonylbis(N-((1H-pyrrol-2-yl)methylene)aniline) (SBPMA) and 2-dimethylamino-5-[(4-{4-[(4-dimethylamino-benzylidene)-amino]-benzenesulfonyl}-phenylimino)-methyl]-benzene (DBBPB), a new class of corrosion inhibitors have been synthesized and their corrosion inhibition efficiency on mild steel in 0.5 M H2SO4 was investigated by mass loss, Tafel polarization and AC impedance measurements. Potentiodynamic polarization studies showed that, these compounds behave as mixed type of corrosion inhibitors. The adsorption process was found to obey Langmuir isotherm model. Electrochemical impedance spectroscopy (EIS) studies revealed that polarization resistance (RP) increases and double layer capacitance (Cdl) decreases as the concentration of the inhibitors increases. Various thermodynamic parameters for the adsorption of inhibitors on mild steel were computed and discussed. FTIR, EDX and SEM analyses were performed to study the film persistency of the inhibitors.
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Mostazo-López, María José, David Salinas-Torres, Ramiro Ruiz-Rosas, Emilia Morallón y Diego Cazorla-Amorós. "Nitrogen-Doped Superporous Activated Carbons as Electrocatalysts for the Oxygen Reduction Reaction". Materials 12, n.º 8 (25 de abril de 2019): 1346. http://dx.doi.org/10.3390/ma12081346.
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Nitrogen-containing superporous activated carbons were prepared by chemical polymerization of aniline and nitrogen functionalization by organic routes. The resulting N-doped carbon materials were carbonized at high temperatures (600–800 °C) in inert atmosphere. X-ray Photoelectron Spectroscopy (XPS) revealed that nitrogen amount ranges from 1 to 4 at.% and the nature of the nitrogen groups depends on the treatment temperature. All samples were assessed as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline solution (0.1 M KOH) in order to understand the role of well-developed microporosity as well as the different nitrogen functionalities on the electrocatalytic performance in ORR. It was observed that nitrogen groups generated at high temperatures were highly selective towards the water formation. Among the investigated samples, polyaniline-derived activated carbon carbonized at 800 °C displayed the best performance (onset potential of 0.88 V versus RHE and an electron transfer number of 3.4), which was attributed to the highest concentration of N–C–O sites.
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Schmid, S. y J. Strähle. "Zur Umsetzung von ReO2I(PPh3)2 mit PhNCO. Synthese und Kristallstrukturen von ReO2I(PPh3)2 · CHCl3, [ORe(OCONPh)I(PPh3)]3, Re(NPh)(NH2Ph)I2(PPh3)(OCONHPh) und Re(NPh)(NH2Ph)I2(PPh3) ( OReO3) / On the Reaction of ReO2I(PPh3)2 with PhNCO. Synthesis and Crystal Structures of ReO2I(PPh3)2 · CHCl3, [ORe(OCONPh)I(PPh3)]3, Re(NPh)(NH2Ph)I2(PPh3)(OCONHPh) and Re(NPh)(NH2Ph)I2(PPh3) ( OReO3)". Zeitschrift für Naturforschung B 46, n.º 2 (1 de febrero de 1991): 235–44. http://dx.doi.org/10.1515/znb-1991-0218.
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PhNCO reacts with oxo ligands at metal centers to form phenyl nitrene complexes. As an intermediate of this reaction we obtained with ReO2I(PPh3)2 (1) the trimeric complex [ORe(OCONPh)I(PPh3)]3 (2) in which the PhNCO moiety was added to an oxo ligand to form an N -phenyl carbamato group. This group acts as a bridging ligand chelating one Re atom via its N and one O atom and coordinating an other Re atom by its second O atom . 2 crystallizes as 2 · 2 CHCl3 in the triclinic space group P1̄ with a = 1423.1(5), b = 2443.3(7), c = 1403.8(6) pm , α = 92.31(3), β = 94.76(3), γ = 81.48(3)°, and Z = 2. From the mother liquor of 2 after a few days Re(NPh)(NH2Ph)I2(PPh3)(OCONHPh) (3) is formed as a partial hydrolysis product. 3 is monoclinic with the space group P21/n and a = 1163.0(4), b = 2527.0(3), c = 1243.9(5) pm, β = 98.04°, Z = 4. The Re atom exhibits an octahedral coordination w ith the two I atom s in a ?ra«s-arrangem ent and the phenyl nitrene ligand trans to the m onodentate PhN HCO2 group. The coordination is completed by a phosphine and an aniline ligand. Reaction of 2 with excess PPh3 yields 1. It crystallizes from CHCl3 as 1 · CHCl3 in the monoclinic space group P21/n with a = 975.9(3), b = 2731(1), c = 1417.3(6) pm , β = 93.35° and Z = 4. In 1 the Re atom is pentacoordinated in form of a trigonal bipyram id with the two phosphine ligands in axial positions. A solution of 2 in THF forms Re(NPh)(NH2Ph)I2(PPh3) (OReO3) (4) upon exposure to air at room temperature. 4 is obtained as orthorhombic crystals with the space group Pca21 and a = 1727(1), b = 1064.2(4), c = 1765.7(9) pm , Z = 4, and is an analogue of 3 from which it can be derived by substituting the carbamato ligand by a perrhenat ion. In 3 and 4 the phenyl nitrene ligand is bound by a Re = N triple bond of 172 pm in a linear arrangement Re = N - Ph .
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Al Hakimi, Nurush Shofi, Ahmand Hanapi y Ahmad Ghanaim Fasya. "Green Synthesis Senyawa Imina dari Vanillin and Anilina dengan Katalis Alami Air Jeruk Nipis (Citrus aurantifolia)". ALCHEMY 5, n.º 4 (16 de enero de 2018): 120. http://dx.doi.org/10.18860/al.v5i4.4706.
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<p class="BodyAbstract">Sintesis imina dari vanilin dan anilina dapat dilakukan tanpa pelarut dengan bantuan katalis asam alami dari jeruk nipis (Citrus aurantifolia). Penelitian ini bertujuan untuk mengkarakterisasi produk imina dengan variasi volume katalis jeruk nipis. Volume katalis jeruk nipis yang digunakan adalah 0,5; 1,0; 1,5; 2,0; dan 2,5 mL. Produk imina dikarakterisasi berdasarkan bentuk, warna, titik lebur dan rendemen. Produk juga identifikasi menggunakan FTIR dan KG-SM. Sintesis imina menghasilkan P1 sebagai produk terbaik dengan rendemen sebesar 64,12% dan tingkat kemurnian 74,74%. Hasil karakterisasi produk imina berupa padatan yang berwarna kuning dengan titik lebur 150°C. Hasil KG-SM menunjukkan adanya senyawa target sintesis 2-metoksi-4-((fenilimino)metil)fenol pada m/z 227 (M<sup>*+</sup>). Terbentuknya senyawa target diperkuat dengan spektra IR khas senyawa imina (C=N) pada 1584 cm<sup>-1</sup>.</p>
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Mao, Meng-Xi, Fang-Ling Li, Yan Shen, Qi-Ming Liu, Shuai Xing, Xu-Feng Luo, Zhen-Long Tu, Xue-Jun Wu y You-Xuan Zheng. "Simple Synthesis of Red Iridium(III) Complexes with Sulfur-Contained Four-Membered Ancillary Ligands for OLEDs". Molecules 26, n.º 9 (29 de abril de 2021): 2599. http://dx.doi.org/10.3390/molecules26092599.
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Phosphorescent iridium(III) complexes have been widely researched for the fabrication of efficient organic light-emitting diodes (OLEDs). In this work, three red Ir(III) complexes named Ir-1, Ir-2, and Ir-3, with Ir-S-C-S four-membered framework rings, were synthesized efficiently at room temperature within 5 min using sulfur-containing ancillary ligands with electron-donating groups of 9,10-dihydro-9,9-dimethylacridine, phenoxazine, and phenothiazine, respectively. Due to the same main ligand of 4-(4-(trifluoromethyl)phenyl)quinazoline, all Ir(III) complexes showed similar photoluminescence emissions at 622, 619, and 622 nm with phosphorescence quantum yields of 35.4%, 50.4%, and 52.8%, respectively. OLEDs employing these complexes as emitters with the structure of ITO (indium tin oxide)/HAT-CN (dipyra-zino[2,3-f,2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile, 5 nm)/TAPC (4,4′-cyclohexylidenebis[N,N-bis-(4-methylphenyl)aniline], 40 nm)/TCTA (4,4″,4″-tris(carbazol-9-yl)triphenylamine, 10 nm)/Ir(III) complex (10 wt%): 2,6DCzPPy (2,6-bis-(3-(carbazol-9-yl)phenyl)pyridine, 10 nm)/TmPyPB (1,3,5-tri(mpyrid-3-yl-phenyl)benzene, 50 nm)/LiF (1 nm)/Al (100 nm) achieved good performance. In particular, the device based on complex Ir-3 with the phenothiazine unit showed the best performance with a maximum brightness of 22,480 cd m−2, a maximum current efficiency of 23.71 cd A−1, and a maximum external quantum efficiency of 18.1%. The research results suggest the Ir(III) complexes with a four-membered ring Ir-S-C-S backbone provide ideas for the rapid preparation of Ir(III) complexes for OLEDs.
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Price, Jason R., Yanhua Lan, Boujemaa Moubaraki, Keith S. Murray y Sally Brooker. "Doubly Pyridazine-bridged Dicobalt(II) and Dinickel(II) Side-by-side Complexes of Variously Substituted Conjugated Bis-bidentate Ligands". Australian Journal of Chemistry 63, n.º 5 (2010): 779. http://dx.doi.org/10.1071/ch09614.
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A family of six acyclic bis-bidentate Schiff base ligands, Lx (prepared by condensation of 3,6-diformylpyridazine with a range of anilines: 2,4-dimethylaniline Lo,p-Me; 3,5-dichloroaniline Lm,m-Cl; 3,5-difluoroaniline Lm,m-F; p-toluidine Lp-Me; 4-aminophenol Lp-OH; 2,4,6-trimethylaniline Lo,o,p-Me), was complexed, 1:1, with cobalt(ii) or nickel(ii) perchlorate or tetrafluoroborate in refluxing dry acetonitrile. A family of dinuclear, doubly pyridazine-bridged complexes, M2II(Lx)2(solvent)n(ClO4)4 and [Ni2(Lo,o,p-Me)2(2H2O)4](BF4)4, resulted. An X-ray crystal structure determination on [Co2II(Lo,o,p)2(H2O)2(MeCN)2](ClO4)4·MeCN confirmed that it has the expected side-by-side architecture with axial solvent molecules completing the octahedral coordination sphere of the two cobalt(ii) ions. Magnetic analysis showed that the pyridazine bridges mediate weak-to-medium antiferromagnetic interactions between the metal ions. Specifically, for the cobalt(ii) complexes J was in the range –12 to –6 cm–1, while for the nickel(ii) complexes J was in the range –22 to –17 cm–1. There is no clear cut correlation of J values with electron-donating or -attracting properties of ligand substituent peripheral groups, although it is noted that the smallest J occurs in both the NiNi and CoCo families for the ligand Lo,o,p-Me.
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Kurtoglu, Nurcan. "Synthesis, characterization, chelation with transition metal ions, and antibacterial and antifungal studies of the 4-[(E)- -phenyldiazenyl]-2-[(E)-(phenylimino)methyl]phenol dye". Journal of the Serbian Chemical Society 74, n.º 8-9 (2009): 917–26. http://dx.doi.org/10.2298/jsc0909917k.
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New Ni(II), Cu(II) and Co(II) complexes were synthesized with the bidentate azo-azomethine dye, 4-[(E)-phenyldiazenyl]-2-[(E)-(phenylimino)methyl] phenol (dmpH), which was prepared by the reaction of 2-hydroxy-5-[(E)- phenyldiazenyl]benzaldehyde with aniline in EtOH. The syntheses of the metal chelates of the azo-azomethine dye were realized by the precipitation technique. The synthesized metal complexes were characterized by elemental analysis, molar conductance measurements, as well as infrared and UV-Vis spectral data. Based on these characterizations, the metal complexes of the transition metal ions may be formulated as [M(dmp)Cl(H2O)] where M = Ni(II), Cu(II) and Co(II). The metal complexes were formed by the coordination of N and O atoms of the ligand. The molar conductance values of the Ni(II), Cu(II) and Co(II) complexes of the bidentate ligand indicate their non-ionic character. The free ligand and its metal complexes were tested for their in vitro antimicrobial properties against eight bacteria: Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Mycobacterium smegmatis, Pseudomonas aeruginosa, Enterococcus cloacae, Bacillus megaterium, and Micrococcus luteus, and three fungi, Kluyveromyces fragilis, Rhodotorula rubra and Saccharomyces cerevisiae, in order to assess their antimicrobial potential. The [Ni(dmp)Cl(H2O)] chelate exhibited high activity against all the bacteria and fungi, except Rhodotorula rubra.
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Mongrain, Pascal, Jasmin Douville, Jonathan Gagnon, Marc Drouin, Andreas Decken, Daniel Fortin y Pierre D. Harvey. "New insights about the hostguest chemistry of the tungsten oxo complex of calix[4]arene, and novel "one pot" difunctionalizations of calix[4]arene using tetrachlorometal(VI) oxide (M = Mo, W)". Canadian Journal of Chemistry 82, n.º 10 (1 de octubre de 2004): 1452–61. http://dx.doi.org/10.1139/v04-097.
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The strong Lewis acid tungsten oxo complex of calix[4]arene can be obtained in both hydrated and non-hydrated forms. This complex coordinates a water molecule inside the cavity via strong O···W interactions with relatively short distances of 2.284(4) and 2.329(2) Å for the tungsten oxo complex of calix[4]arene··H2O·aniline (1), and the tungsten oxo complex of calix[4]arene·H2O·toluene (2·toluene), respectively. The strong interactions are also deduced by the relatively high H2O elimination temperature observed by TGA and DSC (above 200 °C). The coordinated water molecule inside the calix[4]arene cavity is characterized by a strong IR absorption at 3616 cm1, and a narrow resonance at ~1.2 ppm (the chemical shifts of the uncoordinated water are 1.55 and 1.60 ppm in C6D6 and CDCl3, respectively). This water molecule gives rise to H-bonds with aniline in 1. The tungsten oxo complex of 5,11,17,23-tetrabromocalix[4]arene (4), also binds H2O as the characteristic signatures are observed. The successful removal of H2O in 2, is performed under mild conditions using bis(tetrahydrofuran)-uranyl nitrate as a competitive Lewis acid. When this reaction is performed in acetonitrile, butyronitrile or tert-butylnitrile, the corresponding tungsten oxo complexes of calix[4]arene·acetonitrile (3), ·butyronitrile (5), and ·tert-butylnitrile (6) are obtained. The use of uranyl as a H2O abstractor is unprecedented. The X-ray structure of 3 consists of a tungsten oxo complex of calix[4]arene coordinated by an acetonitrile molecule (d(W···N = 2.412(2) Å). The tetra-5,11,17,23-choromethyl-25,26,27,28-tetrahydroxycalix[4]arene reacts with M(O)Cl4 (M = Mo, W) in a 1:1 stoichiometry, via a tetra FriedelCrafts addition of benzene or toluene, followed by a lower-rim complexation of the metal oxide, to form "flower-shaped" calix[4]arenes. This "one pot" double functionalization is unprecedented.Key words: calix[4]arene, tungsten, molybdenum, X-ray, hostguest, FriedelCrafts, Lewis acid, uranyl, DSC, TGA.
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Warttmann, Inge y Günter Häfelinger. "Ab initio MO Optimizations of Osmiumtetracarbonyldihydride and Metallacyclophanes with two Osmium Atoms and their Molecular Complexes with Different Guests". Zeitschrift für Naturforschung B 53, n.º 10 (1 de octubre de 1998): 1223–35. http://dx.doi.org/10.1515/znb-1998-1020.
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AbstractAb initio Hartree-Fock (HF) and density functional (DFT) optimizations on the test m olecule osmiumtetracarbonyldihydride (13) with various basis sets show that the lanl2mb pseudopotential basis set for osmium leads in the HF approximation to more reliable molecular geometries than the DFT calculations. This HF procedure was used for the optimizations of molecular geometries of three isomeric 4,4,4,4,17,17,17,17-octacarbonyl-4,17-diosma[7.7]ortho-, meta- and paracyclophanes 1 to 3, of which 3 was found to be predestined for formation of various host-guest complexes with possible guests benzene (4), fluorobenzene (5), 1,3,5- trifluorobenzene (6), 1,2,4,5-tetrafluorobenzene (7), hexafluorobenzene (8), fluoroanil (9), tetrafluoroethene (10), tetracyanoethene (11) and aniline (12). Results of optimized hostguest geometries are presented graphically for inclusions and associations of guest 4 to 12 with 3. Calculated lanl2mb interaction energies, after correction for basis set superposition error (BSSE), remain favourable only for inclusion of 5 and associations of 5, 10, 11 and 12. Additionally lanl2dz single point calculations for inclusion, which may not need BSSE correction because of the improved basis set, are favourable for 6 and 12. According to lanl2mb HOMO and LUMO energies, 3 may as well easily donate or accept electrons. This may be an interpretation to the surprising effect, that Mulliken total charges are positive on the electron accepting guest molecules 4 to 11. There are geometrical peculiarities in the optimized host-guest complexes for inclusion and association. Fluorine atoms of 5 to 10 and nitrogen atoms of a cyano group of 11 and the amino group of 12 like to come close to one or two carbonyl groups. Similar distances of 2.70 Å to 3.57 Å between the O atom of the carbonyl group and the F atom or N atom appear in all optimizations of inclusion and association of 5 to 12 except in the case of association of tetrafluoroethene (10).
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Shmatko, Valentina A., Tatiana N. Myasoedova, Tatiana A. Mikhailova y Galina E. Yalovega. "Особенности электронной структуры и химических связей в композитах на основе полианилина, полученных бескислотным синтезом". Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 21, n.º 4 (19 de diciembre de 2019): 569–78. http://dx.doi.org/10.17308/kcmf.2019.21/2367.
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Композиты на основе полианилина и CuCl2·2H2O/ZrOCl2·8H2O, в качестве модифицирующих добавок получены методом химической полимеризации без добавления кислоты. Особенности электронной структуры и химических связей образцов исследованы методами ИК спектроскопии и спектроскопии рентгеновского поглощения. Микроструктура поверхности композитов исследовалась методом сканирующей электронной микроскопии. Полианилин в состав композитов входит в частично окисленной форме, степень окисления полимера зависит от типа модифицирующей добавки. Добавление CuCl2·2H2O/ZrOCl2·8H2O в процессе синтеза увеличивает электропроводность образцов
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Chauhan, Dharminder, Madhavi Bandi, Ajita V. Singh, Klaus Podar, Paul G. Richardson, Nikhil C. Munshi, Kristina Viktorsson, Rolf Lewensohn, Jack Spira y Kenneth C. Anderson. "Anti-Myeloma Activity of Enzymatically Activated Melphalan Prodrug J1". Blood 116, n.º 21 (19 de noviembre de 2010): 1838. http://dx.doi.org/10.1182/blood.v116.21.1838.1838.
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Abstract Abstract 1838 Background and Rationale: The alkylating drug melphalan is routinely used in clinical protocols for the treatment of multiple myeloma (MM). Importantly, clinical trials in MM have effectively utilized combination of melphalan with proteasome inhibitor bortezomib and prednisolone (VMP regimen) to reduce toxicity, overcome drug resistance and enhance cytotoxicity. These findings highlight the utility of conventional alkylating agent, and importantly, provide impetus to develop conventional agents based prodrugs with a potent cytotoxic activity. In this context, pharmacological screening of alkylating oligopeptides led to the identification of a novel melphalan-containing prodrug J1 (L-melphalanyl-p-L-fluoro phenylalanine ethyl ester) - a new molecular entity with a more distinct activity profile than melphalan (Gullbo J, et al., Anticancer Drugs 2003,14:617–24; Gullbo J, et al., Invest New Drugs 2004, 22:411–20; Wickstrom M, et al., Mol Cancer Ther 2007, 6:2409–17). J1 is rapidly incorporated into the tumor cells cytoplasm, followed by intracellular hydrolysis in part mediated by aminopeptidase N (APN), resulting in a 10-fold greater release of free intracellular melphalan than exposure to melphalan at the same molar concentration (Gullbo J, et al., J Drug Target 2003,11:355–63; Wickstrom et al., Biochem Pharmacol 2010, 79(9):1281-90). In vitro studies showed a greater cytotoxic potency of J1 versus melphalan against different human solid cancers; however, its effect in MM is undefined. In the present study, we examined the anti-tumor activity of J1 in MM cells using both in vitro and in vivo model systems. Methods and Models: We utilized MM.1S, MM.1R, RPMI-8226, melphalan-resistant derivative of RPMI-8226 (LR-5), KMS12BM, and INA-6 (an IL-6 dependent) human MM cell lines, as well as purified tumor cells from patients with MM relapsing after prior therapies including lenalidomide or bortezomib. Cell viability-, proliferation-, and apoptosis assays were performed using Trypan blue, MTT, thymidine incorporation, and Annexin V/Propidium iodide staining. Signal transduction pathways were evaluated using immunoblot analysis, ELISA, and enzymologic assays. Statistical significance of data was determined using Student t test. Results: As aminopeptidase N (APN) has been shown to play a key role in conversion of J1 into melphalan in solid tumors, we first examined both expression and enzymatic activity of APN in MM cells. Immunoblot analysis showed a high expression of APN in various MM cell lines. Similarly, colorimetric analysis of APN enzymatic activity using the APN substrate L-alanine-4-nitro-anilide demonstrated elevated APN activity in MM cells. Moreover, pre-treatment of MM cells with APN inhibitor Bestatin showed a moderate, but significant blockade of J1-induced cytotoxicity in MM cells (P < 0.05; n=3). We next examined the effects of J1 in MM cells. Treatment of MM cell lines and primary patient cells for 24h significantly decreased their viability (IC50 range 0.5 – 1.0 uM; P < 0.001; n=3) without markedly affecting the viability of normal peripheral blood mononuclear cells, suggesting specific anti-MM activity and a favorable therapeutic index forJ1. Of note, the IC50 range of melphalan for MM cell lines is 10–40 uM. J1-triggered apoptosis was confirmed in MM.1R and RPMI-8226 cells, evidenced by marked increase in Annexin V+ and PI-cell population (P < 0.001, n=3). Importantly, J1induced apoptosis in MM cells even in the presence of MM bone marrow stromal cells. Mechanistic studies showed that J1-triggered apoptosis in MM cells is associated with 1) activation of caspase-7, caspase-8, caspase-9, caspase-3, and PARP; 2) induction of phospho-c-Jun and phospho-JNK, p53, and p21; 3) release of mitochondrial apoptogenic protein cytochrome-c; 4) inhibition of VEGF-induced migration of MM cells and angiogenesis; and 5) induction of DNA damage response, evidenced by increase in phospho-histone H2AX. Pre-treatment of MM cells with pan-caspase inhibitor Z-VAD-fmk attenuated J1-triggered MM cell apoptosis (P value < 0.001; n=3). Finally, treatment of tumor-bearing mice with J1 (3 mg/kg, twice a week for 2 weeks), but not vehicle alone, significantly (P < 0.008) inhibits MM tumor growth in these mice. Conclusions: Our study provides the rationale for clinical protocols evaluating J1, either alone or in combination, to improve patient outcome in MM. Disclosures: Richardson: Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees. Munshi:Millennium Pharmaceuticals: Honoraria, Speakers Bureau. Spira:Oncopeptide AB: Employment, Equity Ownership. Anderson:Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.
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Kammerer, S., P. F. Harmon, S. McDonald y B. Horvath. "First Report of Brown Ring Patch Caused by Waitea circinata var. circinata on Poa annua in Virginia". Plant Disease 93, n.º 4 (abril de 2009): 426. http://dx.doi.org/10.1094/pdis-93-4-0426a.
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Brown ring patch was first described as a disease of cool-season turfgrass on creeping bentgrass (Agrostis palustris) (4) in Japan and later reported in California on annual bluegrass (Poa annua) (2). Brown ring patch symptoms were observed beginning in December 2007 through spring 2008 on 6 of 18 putting greens on a golf course in Reston, VA. Symptoms included yellow rings and patches of blighted turfgrass on the mixed stands of creeping bentgrass (A. palustris) and primarily annual bluegrass (Poa annua). Chlorosis and blight occurred predominantly on P. annua. A turfgrass sample was received from a consultant in April 2008, and disease severity on affected greens was estimated to be 40%. After incubating for 2 days in a moist chamber, Rhizoctonia-like aerial mycelia were observed. The pathogen was isolated on water agar and potato dextrose agar amended with thiophanate-methyl (100 mg/L), rifampicin (100 mg/L), and ampicillin (500 mg/L) from P. annua plants that had been surface sterilized with 70% ethanol for 15 s. Colony and sclerotia morphology were consistent with Waitea circinata var. circinata as previously described (2,4). Hyphae were stained with aniline blue and multiple nuclei were observed per cell. The teleomorph was not observed on plant material or in culture. Amplified fragments of rDNA including internal transcribed spacers from the isolate were amplified in three bacterial clones and sequenced bidirectionally (GenBank Accession Nos. FJ154894, FJ154895, and FJ154896) using primers ITS1/ITS4 (2,4). The consensus sequences matched, with 99% homology and 99% sequence overlap, isolate TRGC1.1 of W. circinata var. circinata (GenBank Accession No. DQ900586) (2). Annual bluegrass was not available for use in performing Koch's postulates, but previous studies have shown that W. circinata var. circinata is pathogenic to roughstalk bluegrass (P. trivialis) (1,3). Pots of P. trivialis cv. Cypress that were 1 week postemergence were inoculated with seven wheat grains that had been autoclaved and then infested with the isolate. Plants were incubated at 25°C in a sealed plastic bag with a moist paper towel on the bottom. Hyphae grew from the grains and colonized the grass. Individual plants began to turn chlorotic within 3 days, and more than 80% of the turf in pots was dead after 1 week. Control pots were inoculated with autoclaved wheat seed and showed no disease symptoms after 1 week. Inoculations were repeated twice more with the same results. W. circinata var. circinata was reisolated from affected plants in all replications of the test. To our knowledge, this is the first report of brown ring patch in Virginia. Additional research is needed to assess the prevalence and importance of this disease on golf course putting greens in Virginia. References: (1) C. M. Chen et al. Plant Dis. 91:1687, 2007. (2) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (3) N. Flor et al. Plant Dis. 92:1586, 2008. (4) T. Toda et al. Plant Dis. 89:536, 2005.
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Indramahalakshmi, G. "Vibrational Spectroscopic Analyses of (en)2-Td-type Clathrates". Asian Journal of Physical and Chemical Sciences, 14 de marzo de 2020, 37–47. http://dx.doi.org/10.9734/ajopacs/2020/v8i130108.
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The clathrates of Hofmann-(en)2-Td-type, M(en)2M’(CN)4.Aniline (M=Cu,Cd; M’=Cd,Zn) and their hosts were synthesized with the confirmation using FTIR spectra. Hydrogen bonding interaction between π-cloud of phenyl ring of the guest molecule and ethylenediamine(en) of the host lattices was deduced from the upward shift in ν(CH)out of plane bending mode of aniline. A second type of hydrogen bonding between C≡N group of the host lattice and NH2 of aniline guest was also inferred from the downward shift in ν(C≡N) of the clathrates. The relative strength of H-bonding in the clathrates was found to be Hofmann-(en)2-Type > Hofmann-(en)2-Td-Phenol > Hofmann-(en)2-Td-Aniline. The presence of major peaks corresponding to various modes of guest aniline, ligand en and cyanide group in FT Raman spectra also confirms the formation of clathrates. Attempts to synthesize Ni(en)2M’(CN)4.Aniline (M’=Cd,Zn) resulted in the formation of M’(en)2Ni(CN)4.2Aniline (M’=Cd,Zn) due to the exchange of metal ions and greater stability of Ni(CN)4 unit.
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"Synthesis, characterization, biological activity of Schiff bases derived from 3-bromo-4-methyl aniline and its potentiometric studies with Cu(II), Co(II) and Ni(II) ions". Letters in Applied NanoBioScience 9, n.º 2 (10 de mayo de 2020): 1015–21. http://dx.doi.org/10.33263/lianbs92.10151021.
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Schiff bases namely, 3-bromo-4-methyl-N-(2-nitrobenzylidene)aniline; 3-bromo-4-methyl-N-(2,4,5-trimethoxybenzylidene)aniline; 3-bromo-N-(4-methoxybenzylidene)-4-methylaniline and N-(3-bromo-4-methylphenyl)-1-(1H-indol-3-yl)methanimine have been synthesized and characterized by elemental analysis, FT-IR, Mass and 1H-NMR spectroscopy. Schiff bases have been screened for Antimicrobial activity against bacteria and fungi by using MIC determination. Binary complexes of Co(II), Ni(II) and Cu(II) with Schiff bases in solution have been studied potentiometrically in 60:40 % (V/V) 1,4-dioxane-water system at constant temperature 27˚±0.5˚C and at an ionic strength of 0.1 M KNO3. The order of stability constant of formed binary complexes in solution was examined.
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Bakare, Safyah B. "Anti-tumor agents: Design, Synthesis, and Biological study of N-Substituted-7-hydroxy-1-azacoumarin-3-carboxamide derivatives as potent cytotoxic agents". Polish Journal of Chemical Technology, 22 de abril de 2021. http://dx.doi.org/10.2478/pjct-2021-0008.
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Abstract Synthesis of ethyl 7-hydroxy-1-azacoumarin-3-carboxylate (3) was developed using ethyl-7-hydroxy coumarin-3-carboxylate and ammonium solution as the key synthons. Condensation of ethyl 7-hydroxy-1-azacoumarin-3-carboxylate with ammonium acetate and aniline to give N-substituted-7-hydroxy-1-azacoumarin-3-carboxamides (7-Hydroxy -1-azacoumarin-3-carboxamide (4) and N-phenyl 7-Hydroxy-1-azacoumarin-3-carboxamide (5)). Bromo derivative (N-phenyl 6, 8-dibromo-7-hydroxy-1-azacoumarin-3-carboxamide (6)) was obtained from halogenation of compound N-phenyl 7-Hydroxy-1-azacoumarin-3-carboxamide (5) with bromine in glacial acetic acid. N-phenyl-2,5-diacetoxy-6, 8-disubstituted-Quinoline-3-carboxamides (N-phenyl 2,7-diacetoxy-Quinoline-3-carboxamide (7) and N-phenyl 2,7-diacetoxy-6,8-dibromo-Quinoline-3-carboxamide (8)) were prepared via the acetylation of compounds 5 and 6 with acetic anhydride. Five compounds 4–8 were evaluated in vitro against more than one human tumor cell lines. Among the selected compounds, 6 showed the best in vitro cytotoxicity against the human cancer cell line; MCF-7 (with IC50 = 10.12 μM). In addition, cell cycle analysis of compound 6 demonstrated cell cycle arrest at G2/M phase and Pre-G1 apoptosis.
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Mohamed, Mohamed Mokhtar y Hassan El-Farsy. "Rapid reduction of nitroarenes photocatalyzed by an innovative Mn3O4/α-Ag2WO4 nanoparticles". Scientific Reports 10, n.º 1 (diciembre de 2020). http://dx.doi.org/10.1038/s41598-020-78542-5.
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AbstractA novel photocatalyst based on the design of P-N heterojunction between hollow spherical Mn3O4 and nanorods shape of α-Ag2WO4 is synthesized using a sonication-deposition–precipitation route. The nanocomposite Mn3O4/α-Ag2WO4(60%) exhibits a great potential towards nitroarenes (including 4-nitrophenol, 4-nitro-aniline and 4-Nitro-acetanilide) reduction under visible light irradiation exceeding that of Mn3O4/α-Ag2WO4(40%) as well as their individual counterparts (3–5%). The Mn3O4/α-Ag2WO4(60%) catalyst exhibited an excellent photo-reduction activity comprised of 0.067 s−1 towards 4-nitrophenol (0.001 M) in only 60 s reaction time using NaBH4 (0.2 M). This was due to the successful formation of the Mn3O4/α-Ag2WO4 composite as validated by XRD, TEM-SAED, XPS, FTIR, UV–Vis diffuse reflectance and PL techniques. Decreasing the Eg value into 2.7 eV, the existence of a new (151) plane in the composite beside enhancement of the composite electrical conductivity (1.66 × 10–7 Ω−1 cm−1) helps the facile nitroarenes adsorption and hydrogenation. Transient photocurrent response and linear sweep voltammetry results prove the facilitation of photogenerated charge carriers separation and transport via improving electron lifetime and lessening recombination rate. The composite photocatalyst produced higher amounts of H2 production, when inserted in a typical reaction medium containing NaBH4, comprised of 470 µ mole/g exceeding those of the counterparts (35 µ mole/g). This photocatalyst is strikingly hydrogenated 4-nitrophenol under mild conditions (25 °C and 0.35 MPa pressure of H2) with magnificent rate constant equal 34.9 × 10−3 min−1 with 100% selectivity towards 4-aminophenol.
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Ibrahim, Michael Ibrahim, Maria Joseph Bassil, Umit B. Demirci, Georges El Hajj Moussa, Vincent Salles, Mario Remond El Tahchi y Philippe Miele. "Photovoltaic Properties of Polyaniline-Titania Composite for Hybrid Solar Cells Applications". MRS Proceedings 1211 (2009). http://dx.doi.org/10.1557/proc-1211-r03-18.
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AbstractSolar energy harvesting has been extensively studied in the last three decades to provide a green energy source. Hybrid photovoltaics (HPV) based on titania (TiO2) are researched for their easiness of production and low cost. Nanostructured mesoporous titania films and conductive polymers were used recently to form hybrid solar cells [1]. TiO2, mainly an n-type semiconductor with a band gap of 4.2 eV, is employed in several applications from which paints form the highest world use of titania making it an attractive material to use in HPV industry. On the other side, our targeted conductive polymer is polyaniline (PANI), a hole conductor polymer, which is used in such HPV cells due to its high charge-carriers mobility, absorption coefficient in the visible range and environmental stability. PANI and nanocrystalline TiO2 films fabricated using spin coating or layer by layer assembly techniques behave as a p-n heterojunction diode and can be used as solar cells [2-4].Precursor solutions are prepared by polymerizing aniline-HCl inside an aqueous solution of titania. To study the effect of the precursor concentration on the PANI-TiO2 composite, polymerization of aniline is held in diverse TiO2 concentrations in water. Industrial grade TiO2 powders with particle size ranging from 200 nm to several μm are used. PANI-TiO2 precursor solutions are dip coated or slot dyed on various substrates such as PMMA, PET and PP, all with metal oxide conductive coatings. Bulk PANI-TiO2 pellets are prepared for comparison. The electrical and photovoltaic properties of the obtained films and pellets are investigated to choose the optimum blend composition for HPV cell. Finally a theoretical study and an analytical model of the HPV cell are presented relating the size of TiO2 and PANI particles and their respective geometrical distribution inside the blend to the transport characteristics of charge carriers and the overall efficiency of the HPV cell.[1] M. McGehee, MRS Bulletin, Vol. 34, No. 2, February 2009.[2] Z. Liu, W. Guo, D. Fu and W. Chen, Synthetic Metals, Vol. 156, pp. 414–416, 2006.[3] Z. Liu, J. Zhou, H. Xue, L. Shen, H. Zang and W. Chen, Synthetic Metals, Vol. 156, pp. 721–723, 2006.[4] X. Zhang, G. Yan, H. Ding and Y. Shan, Materials Chemistry and Physics, Vol. 102, pp. 249–254, 2007.