Synthesis and spectroscopic properties of novel asymmetric Schiff bases

Güngör, Özlem; Gürkan, Perihan

doi:10.1016/j.saa.2010.05.027

Cited by 38 publications

(9 citation statements)

References 22 publications

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“…The third absorption band located at 395 nm is attributed to n→π* transitions of conjugation between the lone pair of electrons and the conjugated bond of the aromatic cycle [61]. The presence of bands above 400 nm such as those at 410 pointed out the existence of a keto-amine tautomer of the ligand [54,64,65]. In the spectrum of the II ligand, the bands at 365 and 305nm were assigned to the imine group and the phenyl ring n→π* and π→π* transitions.…”

Section: Uv/vis Studiesmentioning

confidence: 99%

Synthesis, molecular structure analyses and DFT studies on new asymmetrical azines based Schiff bases

Yahyaoui

Bouchama²,

Anak³

et al. 2019

Journal of Molecular Structure

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In this paper, we report the synthesis of new unsymmetrical azines Schiff bases. These compounds were prepared by condensation of hydrazine with different aldehydes and ketones to give (E) -2-hydroxynaphthalene-1-carbaldehyde [(1E) -2-thienylmethylene] hydrazone compound (I) and (Z) -2 -[(E) -1-(2-hydroxyphenyl) ethylidenehydrazin-1-ylidene] -1,2diphenylethanone compound (II). The method adopted consists in reacting the two different carbonyl compounds simultaneously in one step in a stepwise manner reported which is practical and cost-effective. The reaction with a minor modification in operating conditions proceeded efficiently and with excellent performance. The structure of each of the two compounds (I) and (II) was determined by the X-ray diffraction technique performed on single crystals. The asymmetric unity of the two molecules consists of one asymmetry-independent molecule. In addition, hydrogen bonds C-H ... π are observed in the compound (II). We then present a detailed DFT study based on B3LYP / 6-31G (d, p) geometric structures of compounds (I); (II) and another compound (III) also another asymmetric azine (Z) -2 -[(E) -2-benzylidenehydrazine-1-ylidene] -1,2diphenylethanone whose crystal structure is reported. The fundamental vibration wave numbers are calculated and a good agreement between the observed and calculated wave numbers is obtained. The study was extended to the HOMO-LUMO analysis to calculate the energy gap. The calculated HOMO and LUMO energy reveals that the charge is transferred into the molecule.

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Section: Uv/vis Studiesmentioning

confidence: 99%

Synthesis, molecular structure analyses and DFT studies on new asymmetrical azines based Schiff bases

Yahyaoui

Bouchama²,

Anak³

et al. 2019

Journal of Molecular Structure

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“…In comparison with our previous study, the newly synthesized 3a-n compounds were thought to be in E-isomer form [24]. Although, the phenolic protons of compounds 3a-c, 3e, 3h, and 3k were detected at 14.11-14.40 ppm, as similar to the literature [22,25], the phenolic proton of compound 3l couldn't been determined at the spectrum. The thiadiazole -NH-protons were detected as singlets at 10.39-11.32 ppm, and also the aromatic protons were observed at the expected regions.…”

Section: CLmentioning

confidence: 43%

Synthesis, characterization, antituberculosis activity and computational studies on novel Schiff bases of 1,3,4-thiadiazole derivatives

Türk¹,

Karakuş²,

Maryam³

et al. 2020

jrp

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A series of novel Schiff bases were designed and synthesized by the condensation of 1,3,4-thiadiazoles that contain aromatic primary amine and variously substituted benzaldehydes. The synthesized compounds were screened for their antituberculosis activity against Mycobacterium tuberculosis H37Rv using BACTEC 460 radiometric system. Among the tested compounds, 2-(4-nitrophenyl)amino-5-[4-(3-(4-phenoxy))benzylideneaminophenyl]-1,3,4thiadiazole (3n) showed the highest inhibitory activity (80%). The activities of the newly synthesized Schiff bases were higher in comparison to those of intermediate products 2-(4-aminophenyl)-5-aryl/alkylamino-1,3,4thiadiazoles (2a-l). The computational studies were also performed to estimate drug-like profile of the compounds by using QikProp analysis.

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“…The UV-Vis spectra of all compounds show a low energy band at ~410 nm and two high energy bands at ~288 and ~315 nm. On the basis of the results obtained for other derivatives of different aliphatic and aromatic amines these bands can be assigned to the OH-form, while the one at 410 nm corresponds to the NH form [ 21 , 27 , 28 , 29 ]. The UV-Vis results indicate that the compounds studied exist in an equilibrium of NH- and OH-forms, which is in agreement with the NMR results.…”

Section: Resultsmentioning

confidence: 99%

“…The UV-Vis results indicate that the compounds studied exist in an equilibrium of NH- and OH-forms, which is in agreement with the NMR results. For all compounds studied a more polar solvent shifted the proton transfer equilibrium towards the NH-form [ 27 , 28 , 29 ]. Even for compound 5 which in a chloroform solution is in the pure OH-form, in an ethanol solution a small amount of the NH-form was found.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic Studies of Amino Acid Ionic Liquid-Supported Schiff Bases

et al. 2013

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Amino acid ionic liquid-supported Schiff bases, derivatives of salicylaldehyde and various amino acids (l-threonine, l-valine, l-leucine, l-isoleucine and l-histidine) have been investigated by means of various spectroscopic techniques (NMR, UV-Vis, IR, MS) and deuterium isotope effects on 13C-NMR chemical shifts. The results have shown that in all studied amino acid ionic liquid-supported Schiff bases (except the l-histidine derivative) a proton transfer equilibrium exists and the presence of the COO− group stabilizes the proton transferred NH-form.

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Synthesis and spectroscopic properties of novel asymmetric Schiff bases

Cited by 38 publications

References 22 publications

Synthesis, molecular structure analyses and DFT studies on new asymmetrical azines based Schiff bases

Synthesis, molecular structure analyses and DFT studies on new asymmetrical azines based Schiff bases

Synthesis, characterization, antituberculosis activity and computational studies on novel Schiff bases of 1,3,4-thiadiazole derivatives

Spectroscopic Studies of Amino Acid Ionic Liquid-Supported Schiff Bases

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