- 6-[N-(2-Hydroxyphenyl)aminomethylene]-cyclohexa-2,4-dien-1-one
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The structure determination of the title compound, C13H11NO2, establishes the tautomeric keto form of the salicylaldimine. The asymmetric unit consists of two crystallographically independent molecules which are essentiall
- Mukherjee, Alok K.,De Lal, Rajib,Banerjee, Indrajit,Samanta, Chitra,Nayak, Nirmalya P.
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- Design, spectroscopic properties and effects of novel catechol spiroborates derived from Schiff bases in the antioxidant, antibacterial and DNA binding activity
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Novel catechol spiroborates (L(1–5)B) were prepared from the reaction of the corresponding Schiff base (L(1–5)H) ligands, boric acid, and 3,5-di?tert?butyl catechol under favorable reaction conditions. The synthesized all compounds w
- Kilic, Ahmet,Okumu?, Veysi,S?ylemez, Rahime
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- Schiff base transition metal complexes for Suzuki–Miyaura cross-coupling reaction
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Abstract: Schiff base ligand and its complex with iron (Fe), cobalt (Co), nickel (Ni) and copper (Cu) ions were synthesized using 4-aminoacetophenone and salicylaldehyde and characterized. FTIR spectrum shows that bidentate coordination of metal ions with ligand where O, N are electron donating sites of azomethine group. The geometry of the complexes was deduced from the calculated magnetic moment values and SCXRD analysis. All complexes were studied for their catalytic activity in Suzuki–Miyaura cross-coupling reaction with Cu–L complex showing excellent coupling yield among others. The catalytic activity data show promising results in coupling efficiency, employing cheap, abundant and green metals. Graphical Abstract: Synopsis The transition metal Schiff base complexes synthesized and characterized by SCXRD, Mass spectrometry, TGA, UV–Vis and FTIR analysis. Magnetic susceptibility measurements were also examined to know the plausible geometry of the complex. The synthesized complexes were systematically investigated for Suzuki–Miyaura cross-coupling reactions and optimized to enhance the yield of the Suzuki reaction. [Figure not available: see fulltext.].
- Ansari, Rasheeda M,Bhat, Badekai Ramachandra
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p. 1483 - 1490
(2017/09/25)
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- Design, synthesis and in vitro antimalarial evaluation of new quinolinylhydrazone derivatives
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A series of novel quinolinylhydrazones (5a-f) was synthesized by the condensation reaction of 2,6-diaryl-substituted piperidin-4-ones (4a-f) with 7-chloro-4-hydrazinoquinoline (2). Novel quinolinylhydrazones containing Shiff bases 8a-f and 11a-f were obta
- Thuy, Le Thi,Tien, Hoang Xuan,Hoang, Vu Dinh,Vu, Tran Khac
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scheme or table
p. 163 - 168
(2012/07/17)
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- The substituent effects on the 13C chemical shifts of the azomethine carbon atom of N-(substituted phenyl)salicylaldimines
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Hammett correlations between the 13C-NMR chemical shifts of the azomethine carbon atom and the corresponding substituent constants were established for thirteen Schiff bases. The successful correlation of the chemical shifts with the electrophilic substituent constants σ+ indicate a significant resonance interaction of the substituents on the aniline ring with the azomethine carbon atom in the examined series of imines. The demand for electrons in the investigated compounds was compared to that of the N-benzylideneanilines and N-(substituted phenyl)pyridinealdimines. The manner of transmission of the substituent effects is discussed and they were separated into resonance and inductive effects. The inductive effects prevail over the resonance effects.
- Drmanic, Sasa Z.,Marinkovic, Aleksandar D.,Nikolic, Jasmina B.,Jovanovic, Bratislav Z.
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p. 993 - 1001
(2012/10/29)
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- A study of the tautomers of N-salicylidene-p-X-aniline compounds in methanol
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We have studied the enol-imine→keto-amine tautomeric equilibrium of N-salicylidene-p-X-aniline compounds with X = Me, OMe, NMe2 as electron donor substituents and X = COMe, CN and NO2 as electron acceptor substituents. The equilibrium constants (Ktauo) and standard thermodynamic properties ΔGtauo, ΔHtauo and ΔStauo were measured and calculated in methanol solution at various temperatures, by means of excitation fluorescence spectroscopy. We have analyzed the p-phenylaniline substitution effect on Ktauo and the thermodynamic properties through the Hammett parameters σ. We have performed molecular orbital calculations at the semiempirical AM1 and ab initio HF/3-21G levels to interpret the experimental results, explicitly including the solute-solvent interaction through the formation of an intermolecular hydrogen bond between the salicylidene and methanol molecules. These computational results show a good correlation with the experimental values. An interpretation of the experimental values of TΔSo, based on changes in the molecular structure produced in the enol-imine→keto-amine tautomeric reaction, is proposed.
- Vargas,Amigo
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p. 1124 - 1129
(2007/10/03)
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- Mixed ligand complexes of cobalt(II and III) - Molecular structure of bis-(4-acetophenylsalicylaldiminato)acetylacetonato cobalt(III)
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The bidentate Schiff bases, HL′(= N-4-acetophenylsalicylal-dimine), H″(=N-3-acetophenylsalicylaldimine) and HL? (=N-4-acetophenyl-5-bromosalicylaldimine) do not form complexes with simple cobalt(II)salts, e.g.,Co(CH3COO)2.4H2/s
- De Lal,Banerjee,Mukherjee,Guha
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p. 1050 - 1054
(2007/10/03)
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- Exchange of amine part of schiff bases with ammonia in presence of a metal ion: Molecular structure of bis-(salicylaldiminato) nickel(II)
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The schiff bases N-X1-acetophenyl-X2-salicylaldimines (X1=4 or 3; *X2=H or 5Br) inert to complexation with nickel(II) and cobalt(II) salts undergo very prompt reactions when ammonia is added to the reaction mixt
- De, Rajib Lal,Banerjee, Indrajit,Samanta, Chitra,Mukherjee, Alok K.
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p. 373 - 376
(2007/10/03)
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- GROUND- AND EXCITED-STATE PROTOTROPIC TAUTOMERISM IN ANILS OF AROMATIC α-HYDROXYALDEHYDES STUDIED BY ELECTRONIC ABSORPTION, FLUORESCENCE AND 1H AND 13C NMR SPECTROSCOPIES AND SEMI-EMPIRICAL CALCULATIONS
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Proton transfer processes in both the ground and excited states in anils of aromatic α-hydroxyaldehydes (salicylaldehyde, 2-hydroxynaphthalene-1-carbaldehyde and the novel 10-hydroxyphenanthrene-9-carbaldehyde) have been studied by a combination of spectroscopic techniques.Solution 1H and 13C NMR is used to establish the position of the tautomeric equilibria.UV-visible absorption and fluorescence spectral data help to characterize the existence, in all cases, of excited-state intramolecular proton transfer (ESIPT) phenomena.Semi-empirical calculations involving full geometry optimization and calculation of heats of formation for the ground state (AM1) and vertical excitation energies and oscillator strengths (INDO/S) are in agreement with the experimental observations.
- Alarcon, Sergio H.,Olivieri, Alejandro C.,Cravero, Raquel M.,Labadie, Guillermo,Gonzalez-Sierra, Manuel
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p. 713 - 720
(2007/10/02)
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- Synthesis of Some New &β-Lactams, 4-Thiazolidinones and Pyrazolines
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N-Arylidene-p-aminoacetophenone (I) and N-arylidene-4'-aminochalcones (V) have been converted into a series of substituted β-lactams (III) and 4-thiazolidinones (IV), and pyrazolines (VI, VII) respectively. p-Chloroacetamidoacetophenone (II) has also been converted into series of substituted 4'-piperidino/morpholinoacetoamidochalcones (X) which undergo cyclization on treatment with hydrazine, phenylhydrazine or thiourea to pyrazolines (XI, XII) and pyrimidine-2-thiones (XIII) respectively.The antibacterial and antifungal activities of the compounds have been determined.
- Fahmy, A. M.,Hassan, Kh. M.,Khalaf, A. A.,Ahmed, R. A.
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p. 884 - 887
(2007/10/02)
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