Spectral, electrical conductivity and biological activity properties of some new azopyrimidine derivatives and their complexes

Masoud, Mamdouh S.; Khalil, Ekram A.; Ramadan, Ahmed M.; Gohar, Yousry M.; Sweyllam, Amr M.

doi:10.1016/j.saa.2006.07.047

Cited by 29 publications

(6 citation statements)

References 27 publications

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“…Electronic absorption spectra: S-1,3-Benzothiazol-2ylthiophene-2-carbothiate show strong absorption at 256, 271 and 336 nm. These have been assigned to n-π* and π-π* transitions within the ligand 15 . The existence of many n-π* transition in SBC indicate the presence of elements with non-bonding electrons on the compound.…”

Section: Conductivity Measurementsmentioning

confidence: 99%

“…In [Ce(SBC)2(H2O)2](SO4)2, blue shifts were observed from λmax of 256 nm, 271, 336 nm in SBC to 219, 265 and 316 nm in [Ce(SBC)2(H2O)2](SO4)2. This is as a result of the ligand bonding to the metal through the non-bonding electrons 15,16 . In both complexes, the observed peaks were below 25,000 cm -1 suggesting that there were no charge transfer transition 17 .…”

Section: Conductivity Measurementsmentioning

confidence: 99%

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Synthesis, Characterization and Biological Studies of S-1,3-Benzothiazol- 2-ylthiophene-2-carbothioate and Its Ce(IV) and Nd(III) Complexes

Oruma¹,

Ukoha²,

Asegbeloyin³

2014

Asian J. Chem.

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S-1,3-Benzothiazol-2-ylthiophene-2-carbothioate (SBC) was synthesized by the S-acylation of 2-mercaptobenzothiazole with thiophene-2-carbonylchloride in the presence of pyridine. Its Ce(IV) and Nd(III) complexes were also synthesized. The ligand and its Ce(IV) and Nd(III) complexes were characterized by UV-visible, IR and GC-MS spectroscopy. In addition, the ligand was characterized based on its 1 H and 13 C NMR data and the metal complexes based on conductivity measurement and stoichiometric ratio of combination. The infrared spectral study of S-1,3-benzothiazol-2-ylthiophene-2-carbothioate and its Ce(IV) and Nd(III) complexes gave evidence for coordination through the nitrogen of the benzothiazole ring and carbonyl oxygen. All the complexes were found to contain coordinated water and were assigned octahedral geometry. Antibacterial screening of the compounds were carried out in vitro on Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The compounds showed significant activities against Gram-positive bacteria than Gram-negative bacteria. However, the ligand showed more chemotherapeutic efficacy than the complexes. The compounds were not active against Pseudomonas aeruginosa. Synthesis of S-1,3-benzothiazol-2-ylthiophene-2carbothioate:The ligand was prepared by S-acylation of 2mercaptobenzothiazole with thiophene-2-carbonylchloride in the presence of pyridine which acts as a catalyst 11 . To a solution of 2-mercaptobenzothiazole (2.51 g, 0.015 mole), thiophene-2-carbonylchloride (1.60 mL, 0.015 mole) was added followed by 5 mL of pyridine. The mixture was heated with stirring over a water bath until fumes of hydrogen chloride ceased to appear. About 2 mL of distilled water was added, followed by 2 mL of pyridine to eliminate the excess reagent. The product solidified upon stirring with a glass rod into a white coloured solid. Water (10 mL) was added, the product filtered and recrystallized from dilute ethanoic acid. The yield was 40.38 % and the melting point 162 °C. The spectral results are as follows: UV (λmax nm, cm -1 ) (ethanol): (256, 271, 336); (13, 845,14,657,18,172). IR (KBr, νmax, cm -1 ): 3054 (s), 2985 (m), 1670 (m), 1560 (m), 1497 (m), 1420 (s), 1077 (s), 896 (s), 738 (sh), 706 (w). 1 H NMR (CDCl3) (δ, ppm): 7.15 (1H, d), 7.20 (2H, t), 7.23 (1H, d), 7.25-7.40 (4H, m). 13 C NMR (δ, ppm): 112. 551, 121.412, 124.622, 127.232, 130.365, 141.002, 191.212. Syntheses of Ce(IV) and Nd(III) complexes:The complexes were synthesized by refluxing ethanol solutions of Ce(SO4)2 and Nd(NO3)3·5H2O with the ligand, respectively in amounts equal to metal: ligand molar ratio of 1:2 to ensure complete reaction 6,7 . To ethanolic solution (20 mL) of cerium(IV) sulphate (0.32 g, 0.004 mole) was added a solution of S-1,3benzothiazol-2-ylthiophene-2-carbothioate (2.22 g, 0.008 mole) in ethanol (40 mL). The mixture was refluxed for 1 h under constant stirring at 80 °C. On cooling, milk coloured precipitate formed. They were filtere...

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Section: Conductivity Measurementsmentioning

confidence: 99%

Section: Conductivity Measurementsmentioning

confidence: 99%

Synthesis, Characterization and Biological Studies of S-1,3-Benzothiazol- 2-ylthiophene-2-carbothioate and Its Ce(IV) and Nd(III) Complexes

Oruma¹,

Ukoha²,

Asegbeloyin³

2014

Asian J. Chem.

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“…4 This article is part of a continuing investigation of the structural chemistry of biologically active compounds containing nitroso, nitro and azo chromophoric groups. [5][6][7][8][9][10][11] Here, we aimed to throw light on the solvents effect on the absorption spectra of highly coloured indicators (Sudan orange (SO), Alizarin yellow R (AYR), Aurin tricarboxylic acid (ATA), Alizarin yellow GG (AYGG), Titan yellow (TY) and Eriochrome black-T (EBT)) in the visible and UV region where these compounds absorb due to the extensive conjugation of the azo group with the aromatic rings. Solvents are selected to show a wide variety of solvent parameters and hydrogen bonding capacity, to permit a good understanding of the solvent-induced spectral shifts.…”

Section: Introductionmentioning

confidence: 99%

Solvent, substituents and pH effects towards the spectral shifts of some highly colored indicators

2017

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The solvatochromic responses of six indicators namely Sudan orange, Alizarin yellow R, Aurin tricarboxylic acid, Alizarin yellow GG, Titan yellow and Eriochrome black-T, dissolved in seven solvents of different polarities, have been measured at room temperature. The UV/Vis absorption spectral shifts were analyzed by the multiple linear regression analysis and Kamlet-Taft equation. The observed solvatochromism was found to depend on the presence of the donor and acceptor substituents in the conjugated systems of the indicator and the physical properties of the solvent molecules. The pH effects on the wavenumbers of the absorption band maxima of some indicators with different constituents at room temperature were discussed and the mechanism of ionization was explained. The dissociation constants (pK a) of the investigated compounds were precisely assessed and the existence of the individual predominant ionic species was assigned by constructing distribution diagrams at different pH ranges.

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“…Moreover, certain pyrimidine-pyrazoles have been studied in the fight against cancer [9][10][11][12][13][14][15][16][17]. In our laboratory, Masoud et al recently reported a detailed structural chemistry of azo and nitroso metal complexes [18][19][20][21][22][23][24][25][26] based on spectral and magnetic susceptibility measurements. The following paper aimed to study the stability of biologically active nitroso and nitroso-azo compounds (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Solvatochromism and potentiometic studies of some active nitroso- and nitroso-azo- compounds

et al. 2011

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ester and N-[4-(2-amino-3-hydroxy-pyridin-6-ylazo)phenyl]-acetamide compounds were studied. The dissociation constants were determined potentiometrically. The thermodynamic parameters of dissociation were evaluated. Regression analysis is applied for correlating the different parameters. The results help to assign the solute-solvent interactions and the solvatochromic potential of the investigated compounds. The electronic character of the substituent and the chemical nature of the solvent are major factors for the observed solvatochromism. Nitroso Pyridin-6-ylazo Triazene Effect of solvents Potentiometry Spectrophotometry

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Spectral, electrical conductivity and biological activity properties of some new azopyrimidine derivatives and their complexes

Cited by 29 publications

References 27 publications

Synthesis, Characterization and Biological Studies of S-1,3-Benzothiazol- 2-ylthiophene-2-carbothioate and Its Ce(IV) and Nd(III) Complexes

Synthesis, Characterization and Biological Studies of S-1,3-Benzothiazol- 2-ylthiophene-2-carbothioate and Its Ce(IV) and Nd(III) Complexes

Solvent, substituents and pH effects towards the spectral shifts of some highly colored indicators

Solvatochromism and potentiometic studies of some active nitroso- and nitroso-azo- compounds

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