69 research outputs found
A study on tautomeric investigation of new hetarylazo-6-aminouracil
No full textA series of new heterocyclic disperse azo dyes was prepared by coupling selected diazotized heterocyclic amines with 6-aminouracil. Solvent effects on the UV-visible spectra of the dyes were evaluated. Their colors were discussed with respect to the nature of the heterocyclic ring and the substituents, and the effects of acid and base on their UV-visible absorption spectra
Synthesis and spectral properties of new hetarylazo indole dyes
No full textA series of new hetarylazo indole dyes were synthesized by azo coupling of 2-phenyl-, 2-methyl-, and 1-methyl-1-phenyl-1H-indole with diazonium salts derived from 5-methylsulfanyl-1H-1,2,4-triazol-3-amine, 1H-1,2,4-triazol-3- amine, 5-methylisoxazol-3-amine, and 5-amino-1,3,4-thiadiazole-2-thiol. The dyes were characterized by the IR spectra, electronic absorption spectra in the UV and visible regions, and 1H NMR and mass spectra. The effects of solvent nature, acidity of the medium, temperature, and concentration on the electronic absorption spectra in the visible region and the dependence of the color of the dyes on the nature of heterocyclic fragment were examined. © 2007 Pleiades Publishing, Ltd
2-amino-4-(4-methoxyphenyl)-1,3-thiazole
No full textThe molecule of the title compound, C10H10N2OS, is not planar, with a dihedral angle of 14.8 (2)degrees between the planes of the benzene and thiazole rings. Molecules are linked by intermolecular N-H center dot center dot center dot O and N-H center dot center dot center dot N hydrogen bonds between the amino H atoms and O and N atoms of the methoxy group and thiazole ring, respectively, forming an infinite chain
Synthesis, molecular structure and computational study of (Z)-2-((E)-4-nitrobenzylidene)hydrazone)-1,2-diphenylethan-1-one
No full textA new benzilmonohydrazone, (2)-2-((E)-4-nitrobenzylidene)hydrazone)-1,2-diphenylethan-l-one (BMH) has been synthesized for the first time. It was characterized by UV-vis, FT-IR, FT-Raman, H-1/C-13 NMR and mass spectrometry techniques. Molecular structure of the title compound was determined by single crystal X-ray diffraction study. In addition, molecular structure of BMH was determined by single crystal X-ray diffraction technique and found that the compound crystallizes in triclinic, space group P-1. Furthermore, chemical calculations employing density functional theory (DFT) method were performed to study the structural and spectroscopic properties of BMH, and the results were compared with the experimental findings. (C) 2015 Elsevier B.V. All rights reserved
Synthesis and investigation of various properties of a novel series of nonlinear optical (NLO) chromophores bearing dicyanovinyl (DCV) moiety
No full textA series of new nonlinear optic (NLO) chromophores containing a dimethine (vinyl) as it-bridge and electron acceptor dicyanomethine and different electron-donating groups and heterocyclic rings were synthesized. The structures of synthesized dyes were characterized by Fourier Transform Infrared (FTIR), proton and carbon nuclear magnetic resonance (H-1/C-13 NMR) and mass spectrometry. Their electronic absorption spectra were evaluated in MeOH, THE and DCM. The absorption maxima exhibited little bathochromic shifts for each dye with the increasing dielectric constants of the solvents. The synthesized dyes can absorb in the range of 354-506 nm. The analysis of the electronic spectra showed that the dyes having electron-donating groups or heterocyclic rings showed significant changes relative to the model dye which has no substituent on the phenyl ring. In addition, the absorption maxima moved to the longest wavelength for dye containing N,N-dibutylamino substituent. Experimental absorption wavelengths for the compounds were found to be in good agreement with those predicted using the Time Dependent Density Functional Theory (TD-DFT) [B3LYP/6-311 + g(d,p)]. Furthermore, the second order NLO responses of the dyes were calculated using density functional theory (DFT) calculations. The study reveals that the synthesized chromophores have large first hyperpolarizability (beta) values, hence they may have potential applications in the development of NLO materials. For determination of the thermal behaviors of the compounds, thermogravimetric analysis (TGA) were done. The result showed that all the chromophores exhibited good thermal stabilities with the decomposition temperatures (T-d) greater than 260 degrees C. (C) 2017 Elsevier B.V. All rights reserved
]pyrimidine; Syntheses, Photophysical Properties, and Investigation of Protonation Ability
No full textA novel series of 2-coumarin-3-yl-imidazo[1,2-a]pyrimidines have been synthesized with functionalized coumarin and pyrimidine units of the different architecture to give various fluorescent compounds. A new additional series bearing unsubstituted coumarin and 7-dialkylaminocoumarin as fluorophore were obtained by palladium-catalyzed cross-coupling reactions, through coupling of 6-bromo-2-coumarin-3-yl-imidazopyrimidine derivatives with various arylboronic acids. In the all reaction step, microwave irradiation (MWI) method was used and compared with the conventional method (CM). Photophysical properties of synthesized compounds were studied by a combination of UV/Vis and fluorescence spectroscopy in various solvents having different polarities. The protonation abilities of all compounds were investigated by titration with trifluoroacetic acid (TFA) in dichloromethane. In both series, the compounds bearing 7-dialkylaminocoumarin are fluorescently active even in daylight and showed maximum absorption wavelengths (lambda(abs-max)) in the visible region in all solvents used. In addition, they showed drastic color and emission change in acidic environment. Moreover, for the investigation of protonation ability of three selected compounds bearing 7-dialkylaminocoumarin have been studied using a buffer solution with various pH and determinated their pK(a) values. The compound bearing morpholine has the potential to use as colorimetric and luminescence pH sensor. The thermal properties of all the synthesized compounds were also evaluated with TGA to test their usability as optic dyes
Fluorescence Interaction and Determination of Calf Thymus DNA with Two Ethidium Derivatives
No full textIn this paper, we reported the syntheses and investigation of the modes of binding to DNA of the two new ethidium derivatives containing benzoyl and phenylacetyl groups of both amines at 3-and 8- positions. The interactions between calf thymus DNA (ct-DNA) and the two derivatives, 3,8-dibenzoylamino-5-ethyl-6-phenylphenantridinium cloride (E2) and 3,8-diphenylacetylamino-5-ethyl-6-phenylphenantridinium chloride (E3), were investigated by fluorescence quenching spectra and UV-vis absorption spectra. The Stern-Volmer quenching constants, binding constants, binding sites and the corresponding thermodynamic parameters Delta H, Delta S and Delta G were calculated at different temperatures. The results indicated the formation of E2 and E3-DNA complexes and van der Waals interactions as the predominant intermolecular forces in stabilizing for each complex. In addition, increasing nucleophilicity of the functional groups at 3- and 8- positions exhibited the respectable increment the DNA binding affinities of derivatives. The results of absorption, ionic strength and iodide ion quenching suggested that the interaction mode of E2 and E3 with ct-DNA was intercalative binding. The limit of detection (LOD) of ct-DNA were 7.49 x 10(-8) (n = 4) and 4.18 x 10(-8) mol/l (n = 7) in presence of E2 and E3, respectively
3-[5,6-Dimethyl-1,3-benzothiazol-2-yl)-diazenyl]-1-methyl-2-phenyl-1H-indole
No full textIn the title compound, C24H20N4S, the phenyl ring forms a dihedral angle of 49.22 (7)degrees with the indole ring system. The indole and benzothiazole ring systems are both approximately planar, with dihedral angles between the five-and six-membered rings of 0.98 (7) and 1.28 (5)degrees, respectively. They are also oriented relative to the central N=N double bond at angles of 3.12 (14) and 3.82 (10)degrees, respectively
Synthesis of new hetarylazoindole dyes from some 2-aminothiazole derivatives
No full textA new series of heterocyclic disperse dyes were prepared by diazotization of some 2-aminothiazole derivatives and subsequent coupling with indole compounds. The dyes were characterized by UV-Vis, FT-IR, 1H NMR, and mass spectra (LC-MS). Solvent effects on their visible absorption spectra were estimated. The color of the dyes is discussed with respect to the substituent therein. The effects of acids and bases on the visible absorption maxima of the dyes are also reported. Replacement of methyl group in the 4-position of the thiazole ring by phenyl group leads to red shift of the absorption maximum due to π-electron-donating properties of the phenyl group, while weak electron-withdrawing chlorine or bromine atom in the para-position of the phenyl group in the 2-amino-4-phenylthiazole fragment induce a small blue shift relative to 2-amino-4-phenylthiazole derivatives. Introduction of an electron-withdrawing 4-nitrophenylsulfonyl group into the thiazole ring produces bathochromic shift of the absorption maximum in all solvents. © 2008 MAIK Nauka
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