- Synthesis, spectral properties of 1-substituted phenyl-3-(p- methoxycarbonyl)phenyl-5-phenylformazans
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Formazans 1-14 were prepared by the coupling reaction of phenylhydrazones and diazonium salts of aniline or -NO2, -CH3, -OCH3, -I, substituted anilines. The phenylhydrazones were synthesized by condensation of benzaldehyde or methyl-4-formylbenzoate with phenylhydrazine. The structures of the compounds were confirmed by IR, 1H NMR and 13C NMR. The dependence of ?max upon the type of substituents and their positions on the phenyl ring was investigated using UV-visible spectra.
- Sen?z, Hülya,Yildirim, Ebru,Tezcan, Habibe
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p. 2989 - 2993
(2013/05/09)
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- Synthesis, spectroscopy, and quantum-chemical calculations on 1-substituted phenyl-3,5-diphenylformazans
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In this study 1-substituted phenyl-3,5-diphenylformazans were synthesized from benzaldehyde-N-phenylhydrazone and appropriate phenyldiazonium salts having CH3, Br, and Cl at the o-, m-, and p-positions of 1-phenyl ring. Their structures were determined by infrared and ultraviolet-visible spectra. Bathochromic effect in accordance with the electron-donating effect of CH3, Br, and Cl group and its magnitude were dependent upon type and position of substituent on the ring. The ground-state geometries and absorption wavelengths for 1-phenyl substituted formazans were studied with density functional theory and time-dependent density functional theory. The calculations were carried out by using PBE1PBE functional with 6-311G(2d,2p) basis set for λmax of the UV-vis spectra for the studied formazans. A good agreement was obtained between the experimental and computed values.
- Tezcan, Habibe,Tokay, Nesrin
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experimental part
p. 54 - 60
(2010/03/04)
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- Arylations mediated by lead(IV) in the presence of formazan and imine ligands
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The use of formazan and imine ligands in arylations of β-dicarbonyl systems by phenyl boronic acid/lead(IV) carboxylates is examined.
- Iqbal, Amjid,Moloney, Mark G.,Siddiqui, Hamid Latif,Thompson, Amber L.
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scheme or table
p. 4523 - 4525
(2009/12/03)
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- Electrochemical studies of verdazyl radicals
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(Chemical Equation Presented) The redox properties of verdazyl radicals are presented using cyclic voltammetry techniques. These radicals can be reversibly reduced as well as oxidized. Electron-donating and -withdrawing substituents have significant effects on the oxidation and reduction potentials as well as the cell potential (Ecell = |Eox° - E red°|) for these radicals; a correlation between the electron spin distribution and redox properties is developed.
- Gilroy, Joe B.,McKinnon, Stephen D. J.,Koivisto, Bryan D.,Hicks, Robin G.
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p. 4837 - 4840
(2008/03/18)
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- A colorimetric assay for screening transketolase activity
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A tetrazolium red-based colorimetric assay has been devised to screen for transketolase activity with a range of aldehyde acceptors. The colorimetric TK assay is able to detect >8% bioconversion using non-α-hydroxylated aldehydes as acceptor substrates an
- Smith, Mark E.B.,Kaulmann, Ursula,Ward, John M.,Hailes, Helen C.
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p. 7062 - 7065
(2007/10/03)
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- Oxidation of 3-(3-or 4-pyridyl)-1,5-diphenylformazans in tetrazolium trichlorometallates: Structural and electrochemical investigation
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On interacting pyridine-containing formazans with cobalt(II) and copper(II) chlorides the richlorometallates of the corresponding cations are isolated, the structures of which were established by X-ray structural analysis. Using data of cyclic voltamperometry a scheme is proposed for the oxidation-reduction process of converting formazans into tetrazolium cations.
- Frolova,Vatsadze,Stash,Rakhimov,Zyk
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p. 1444 - 1456
(2008/09/21)
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- Reducing ability of supramolecular C60 dianion toward C=O, C=C and N-N bonds
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Different from C60 dianion which readily reacts with electrophiles, supramolecular C60 dianion (2) generated from γ-cyclodextrin-bicapped C60 (1) and NaBH4 (or diborate) in DMSO-H2O (9:1, v/v) is able to reduce N-N+, C=C-EWG and C=O bonds to provide the respective dihydro derivatives; 1-mediated reduction of acetophenone with NaBH4 in the presence of (Me 2N)2CH2 and EtONa gives turn over frequency (TOF)/h of 400. The Royal Society of Chemistry 2005.
- Takekuma, Shin-Ichi,Takekuma, Hideko,Yoshida, Zen-Ichi
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p. 1628 - 1630
(2007/10/03)
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- Syntheses of formazans under phase-transfer conditions
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Several 1,3,5-triarylformazans were synthesized (42-77%) using a new methodology. Azo-coupling of aryldiazonium salts with arylaldehyde arylhydrazones under mild basic conditions in two-phase liquid-liquid media is efficiently promoted by phase-transfer catalysts (onium salts or dicyclohexano-18-crown-6) at 5-25°C. The condensation of benzaldehyde with phenylhydrazine followed by phase-transfer catalyzed azo-coupling with phenyldiazonium chloride (one-pot procedure) gave 1,3,5-triphenylformazan in a 54% yield without isolation of the intermediate benzaldehyde phenylhydrazone. A double azo-coupling reaction of phenyldiazonium chloride with 9 different CH-active compounds afforded corresponding formazan only in the case of phenylpyruvic acid. Reaction in malonamide gave 3-carbamoyl-1,5-diphenylformazan instead of the expected 1,5-diphenylformazan.
- Katritzky,Belyakov,Cheng,Durst
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p. 577 - 581
(2007/10/02)
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- New Synthesis of Macrocyclic Crown-Formazans from Pyruvic Acid Derivatives
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The macrocyclic crown-formazans 7a-c, 12a-g were prepared by the azo-coupling of the appropriate bis-diazonium salts 4a-c with pyruvic acid and arylpyruvic acids 8a-c.The ready accessability of the latters offers an easy access towards 1,5-symmetrically d
- Ibrahim, Yehia A.,Elwahy, Ahmed H. M.,Abbas, Ashraf A.
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p. 11489 - 11498
(2007/10/02)
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- Tailoring Magnetic Interactions of Organic Solids: Modification of Triphenylverdazyl
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Crystal Structure / Magnetism / Radicals / Spectroscopy, Electron Spin Resonance The synthesis of the free radicals 1-(4'-bromophenyl)-3,5-diphenyl-verdazyl (Br-TPV), 1-(4'-isopropylphenyl)-3,5-diphenyl-verdazyl (IP-TPV), 1,3,5,6-tetraphenyl-verdazyl (Ph-
- Dormann, E.,Winter, H.,Dyakonow, W.,Gotschy, B.,Lang, A.,et al.
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p. 922 - 930
(2007/10/02)
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- Photochemistry of Aqueous Solutions of Triphenyltetrazolium Chloride
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The photodisproportionation of triphenyltetrazolium chloride (TTC) was studied by flash spectrophotometry in aqueous solution at 23-24 deg C and pH between 9.0 and 11.5.Several intermediates were found to be involved in the photoreductive patway and its s
- Gonzalez, Monica C.,San Roman, Enrique
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p. 3536 - 3540
(2007/10/02)
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- OXIDATIONS OF ENONE SYSTEMS IN STEROIDS BY OXIDIZERS WITH REVERSIBLE REDOX POTENTIAL
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The oxidation of steroid enones by oxidizers with reversible redox potentials (mostly tetrazolium salts) is described.Products containing an oxo or hydroxy group at the position γ with respect to the oxo of the enone group were isolated in relatively high yields.The results of kinetic studies on the redox processes are reported and a reaction mechanism is proposed.
- Jasiczak, Jan
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p. 2687 - 2692
(2007/10/02)
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- 2,3,3,4,6-PENTAPHENYL-1,2,3,4-TETRAHYDRO-SYM-TETRAZINE AND ITS RADICAL-CATION
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A method for the production of 2,3,3,4,6-pentaphenyl-1,2,3,4-tetrahydro-sym-tetrazine and its radical-cation is described; an analysis is made of the hyperfine structure in the observed ESR spectrum.The obtained data are interpreted in accordance with the results from quantum-chemical calculations of the electronic structure in model leucoverdazyl radical-cations.
- Nesterenko, A. M.,Polumbrik, O. M.,Markovskii, L. N.
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p. 1722 - 1725
(2007/10/02)
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