- Synthesis, characterization and density functional theory investigations of the electronic, photophysical and charge transfer properties of donor-bridge-acceptor triaminopyrazolo[1,5-a]pyrimidine dyes
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We have synthesized multifunctional dyes 3-(4-methyl-phenylazo)-6-(4-nitro- phenylazo)-2,5,7-triaminopyrazolo[1,5-a]pyrimidine (4a) and 3-(4-methyl- phenylazo)-6-(4-acetyl-phenylazo)-2,5,7-triaminopyrazolo[1,5-a]pyrimidine (4b), then characterized by IR, 1H NMR and 13C NMR techniques. The ground state geometries have been computed by using density functional theory at B3LYP/6-31Ga?- level of theory. The absorption spectra have been calculated by using time dependent density functional theory with and without solvent. The highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) are delocalized and localized on throughout the backbone, respectively. Solvent also play important role towards elevating the dipole moment. Significant red shift in absorption wavelengths have been observed in methanol compared to without solvent. We discussed the electron injection, electronic coupling constant and light harvesting efficiency.
- Al-Sehemi, Abdullah G.,Irfan, Ahmad,Fouda, Ahmed M.
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- Novel heterocyclic disazo dyes containing pyrazole and phenylpyrazole. part 1: Synthesis, characterization, solvent polarity and acid-base sensitive characteristics
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A series of diazotised aniline and aniline derivative compounds were reacted with solution of malononitrile in pyridine at 0–5 °C were obtained 1a-1m compounds. Then 4-arylazo-3,5-diamino-1H-pyrazole (2a-2m) derivatives were synthesized by coupling arylazo malononitrile compounds with hydrazine. Finally, the synthesized pyrazole derivative 2a-2m compounds were again diazotised. By reacting these diazotised compounds with 3-amino-5?hydroxy-1-phenylpyrazole, the new thirteen heterocyclic disazo dyes (3a-3m) were joined the dye literature and the dye industry. The structures of these newly synthesized compounds were characterized using elemental analysis and spectroscopic methods such as Fourier transform infrared spectroscopy-Attenuated total reflectance (FT-IR-ATR), 1H-Nuclear magnetic resonance (1H NMR) spectroscopy and mass spectroscopy. Then solvatochromic properties and solvent effect in dimethyl sulfoxide, dimethyl formamide, acetonitrile, acetic acid, methanol and chloroform were investigated. In addition, the effects of organic and inorganic acids and bases on the absorption spectra of the compounds and the substituent effect of the phenyl ring-bound groups were investigated.
- Demir?al?, Aykut
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- Synthesis, absorption properties and biological evaluation of some novel disazo dyes derived from pyrazole derivatives
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In this study, 20 novel disazo dyes containing pyrazole derivatives were synthesized by a convenient method. Diazotized aniline and some aniline derivatives were reacted with malononitrile to give 2-arylazomalononitrile derivatives 1(a-e). The synthesized 2-arylazomalononitrile derivatives were reacted with hydrazine and phenyl hydrazine to afford the corresponding 3,5-diamino-4-arylazo-1 H-pyrazole 2(a-e) and 3,5-diamino-4-arylazo-1-phenylpyrazole 3(a-e). Diazotized compounds of 2(a-e)and 3(a-e) reacted with ethylacetoacetate to give 4-arylazo-3-amino-1 H-pyrazole-5-ylazo-ethylacetoacetate 4(a-e) and 4-arylazo-3-amino-1-phenylpyrazole-5-ylazo-ethylacetoacetate 7(ae). The obtained 4(a-e) and 7(a-e) were reacted with hydrazine and phenyl hydrazine to give disazo dyes 5(a-e), 6(a-e), 8(a-e) and 9(a-e), respectively. The synthesized disazo dyes were characterized by spectroscopic techniques as well as elemental analysis. The solvatochromic behaviours of these dyes in various solvents were examined. Acid-base effects on the absorption maxima of the dyes were also reported. Antimicrobial activities of the synthesized novel disazo dyes were investigated.
- Sener, Nesrin,Sener, Izzet,Yavuz, Serkan,Karci, Fikret
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p. 3003 - 3012
(2015/12/11)
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- DFT, FT-IR, FT-Raman and NMR studies of 4-(substituted phenylazo)-3,5- diacetamido-1H-pyrazoles
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We present a detailed analysis of the structural and vibrational spectra of some novel azo dyes. 2-(Substituted phenylazo)malononitriles were synthesized by the coupling reaction of the diazonium salts, which were prepared with the use of various aniline
- Kinali, Selin,Demirci, Serkan,?ali?ir, Zühre,Kurt, Mustafa,Ata, Ahmet
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scheme or table
p. 254 - 258
(2011/06/27)
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- Synthesis and characterization of Ni(II) and Cd(II) complexes of 4-(4-nitrophenylazo)- 1H-pyrazole-3,5-diamine and 4-(4-methylphenylazo)-1H- pyrazole-3,5-diamine
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In this study, the diazotized p-nitroaniline and p-methylaniline were coupled with malononitrile. The ring closure reaction of the obtained products with hydrazine monohydrate yielded 4-(4-methylphenylazo)-1H-pyrazole-3,5-diamine (L1) and 4-(4-nitrophenylazo)-1H-pyrazole- 3,5-diamine (L 2). The structure of the ligands has been elucidated by spectroscopic analyses. Then, novel Ni(II) and Cd(II) complexes of the ligands have been synthesized and the structures of these complexes determined by elemental analysis, spectrometric and TGA/DTA methods, molar conductance and magnetic susceptibility measurements. All the complexes were monomeric and diamagnetic. From the elemental analyses and mass spectra data, the complexes were proposed to the formulae [Ni2(L1)2(OH) 2]·2Cl·8.5H2O, [Cd2(L 1)2(OH)2]·2Cl·DMF·3H2O, [Ni(L2)2]·2Cl·2DMF·7H2O and [Cd2(L2)2(OH)2(H 2O)4]·2Cl·1.5H2O. For the Cd(L2) complex octahedral geometry was proposed, but the Ni(L 1), Ni(L2) and Cd(L1) complexes show four coordinated structure. The Ni(L1), Cd(L1) and Cd(L 2) complexes were found to be dinuclear. On the other hand the Ni(L2) complex was found to be mononuclear. All the complexes were found to be (1:2) electrolytes.
- Adiguzel, Ragip,Esener, Hasan,Ergin, Zuhal,Aktan, Ebru,Turan, Nevin,Sekerci, Memet
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scheme or table
p. 2795 - 2800
(2012/01/30)
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- Studies on 3,5-Diaminopyrazoles: New Routes for the Synthesis of New Pyrazoloazines and Pyrazoloazoles
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The reactions of 3,5-diaminopyrazoles with α,β-unsaturated nitriles, active methylene reagents and nitrile imines are described.The investigations make several new pyrazoloazines and pyrazoloazoles accessible.
- Elfahham, Hassan Attia,Elgemeie, Galan Eldin Hamza,Ibraheim, Yusria Rizk,Elnagdi, Mohamed Hilmy
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p. 819 - 822
(2007/10/02)
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