51 research outputs found
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
Synthesis and investigation of photophysical, NLO and thermal properties of D-pi-A-pi-D dyes
No full textA novel coumarin-thiophene based dyes containing azo and dimethine bridges with D-pi-A-pi-D system were synthesized and investigated their photophysical, nonlinear optical (NLO) and thermal properties. The dyes were characterized by FT-IR, H-1-NMR, C-13-NMR and HRMS. The dyes include dicyanomethylene group as acceptor and different para-substituted alkylamines and carbazole as donor and chlorophenyl as weak acceptor. The photophysical properties of dyes were examined in various solvents with different polarities and they showed absorption in the visible region. The significant bathochromic shifts were observed in the absorption maxima with increasing the electron-donating property of substituents. The second order NLO responses of the compounds are measured by the electric field induced second harmonic (EFISH) generation method and the compounds bearing dialkylamino donor in phenyl moiety were obtained as the larger mu beta values 1300 x 10(-48) esu, 1850 x 10(-48) esu, respectively, than unsubstituted derivative in phenyl ring mu beta value 350 x 10(-48) esu. The structural and electronic properties of the compounds as well as their NLO properties were studied using DFT calculation. The thermal stabilities obtaining with thermogravimetric analysis (TGA) showed that the dyes have generally a good thermal stability up to 250 degrees C. (C) 2020 Elsevier B.V. All rights reserved
Phenylazoindole dyes 3: Determination of azo-hydrazone tautomers of new phenylazoindole dyes in solution and solid state
No full textA new two series of phenylazo indole dyes was synthesized and the structures of the dyes were confirmed by UV vis, FT-IR, HRMS and H-1/C-13 NMR spectroscopic techniques. Five of these dyes (I, I', II', HI and were also characterized in solid state by using single crystal X-ray diffraction studies besides other spectroscopic techniques. The geometries of the azo and hydrazone tautomeric forms of the dyes were optimized by using Density Functional Theory (DFT). In addition, the effects of the donor and acceptor groups on the azo and hydrazone forms of the dyes were evaluated experimentally and theoretically. The results indicate that the phenylazoindole dyes derived from 2-phenyl indole as coupling component exist as azo form in solution, gas phase and solid state. (C) 2014 Elsevier B.V. All rights reserved
Synthesis, characterization, molecular docking and in vitro screening of new metal complexes with coumarin Schiff base as anticholine esterase and antipancreatic cholesterol esterase agents
No full textIn this work, Combining coumarin and thiazole with 3-tertiary butyl salicylaldehyde into in a single molecule, new Schiff base (CTS), and its metal complexes with palladium and platinum were synthesized and characterized by using well-known spectroscopic techniques such as H-1-NMR, C-13-NMR, FT-IR and LC-MS. And also, the formation of these complexes were confirmed by magnetic moment and conductivity measurements. The photophysical properties of CTS were studied and it was observed that the Schiff base has a sensitivity to CN-, F-, and AcO- anions. The quantum chemical calculations based on density functional theory (DFT) were done for explaining some experimental, structural, and spectroscopic data of the dyes. Also, to evaluate the binding interactions between the ligand (CTS) and its metal complexes and enzymes, molecular docking studies were performed and all the compounds tested to determine its inhibition potential against the cholinesterase (AChE and BChE) and pancreatic cholesterol esterase (CEase) enzymes. Both in vitro and in silico the results showed that all of the compounds could act as potent inhibitors of AChE, BChE, and CEase. The Pt (II) complex showed the most potent inhibitory property against all of the enzymes with IC50 values of 12 mu M for AChE, 23 mu M for BChE, and 21 mu M for CEase
Triphenylamine-based allylidenemalononitrile chromophores synthesis, and photophysical and second-order nonlinear optical properties
No full textInternational audienceA series of chromophores based on a mono-, di- or tri-substituted triphenylamine core and allylidenemalononitrile fragments has been designed. The linear and second order nonlinear optical properties as well as thermal stability of the chromophores have been studied experimentally. Structure-property relationships, in terms of the branching effect on the triphenylamine core and the influence of the aniline/coumarin part on the photophysical properties and NLO response, have been highlighted. The experimental results have been rationalized by theoretical calculations
A novel and synthetically facile coumarin-thiophene-derived Schiff base for selective fluorescent detection of cyanide anions in aqueous solution: Synthesis, anion interactions, theoretical study and DNA-binding properties
No full textA colorimetric and fluorescent chemosensor (chemosensor 2) for the detection of cyanide anions in aqueous solution has been designed and synthesized in high yield. The sensing mechanism of the chemosensor was verified via UV-vis, fluorimetric, and NMR titrations, and was theoretically explained using DFT and TD-DFT calculations. The chemosensor could optically discriminate the presence of fluoride ions over other anions by a color change from yellow to red with an enhancement of pink fluorescence in DMSO. However, it showed strong green fluorescence when CN- was added to a mixture of DMSO/water (6:4 v/v). Thus, the chemosensor can be employed in selective detecting of CN- besides other interference anions (F-, AcO(- )and H2PO4-) in aqueous solution. Moreover, 2 can be used to detect CN(- )at a concentration as low as 0.32 mu M, which is lower than the WHO guideline (2.7 mu M) for cyanide. A low quantity of CN- (1.08 mu M) can be detected and quantified using the prepared chemosensor. Moreover, the UV-vis and fluorescence spectroscopy studies of the interactions between 2 and dublex DNA revealed intercalative binding of calf thymus DNA to the chemosensor. (C) 2018 Elsevier Ltd. All rights reserved
Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties
No full textHerein we report the synthesis and characterization of a new series of styryl-based push-pull dyes containing a free amino group and their Schiff base derivatives. The dyes include the dicyanomethylene group as an acceptor and different para-substituted alkylamines as donors. Morever as a proton-sensitive group a pyridin-2-yl substituent was attached to the para-position of the phenyl moiety in both series of compounds. The photophysical properties of the dyes were examined in various solvents with different polarities and showed absorption in the visible region and green-red emission with low quantum yields. The absorption and the emission maxima were shifted bathocromically by increasing the solvent's polarity. However, there was no correlation with the polarity parameters of the solvents. The pH-sensitive properties of all prepared Schiff bases were examined against TBAOH in DMSO, via deprotonation of the OH group in the salicylidene moiety and their reverse protonation was also investigated using TFA. The Schiff bases exhibited a bathochromic shift upon the addition of TBAOH to their solutions in DMSO. Therefore, they showed potential to be utilized as colorimetric and luminescence pH sensors. The second-order nonlinear optical (NLO) responses of the dyes were measured by the electric field-induced second harmonic (EFISH) generation method. The highest mu beta values were obtained for the dyes bearing the julolidine donor as 1430 x 10(-48) esu (for free amino derivative) and 1950 x 10(-48) esu (for Schiff base derivative), respectively. The structural and electronic properties of the dyes as well as their NLO properties were further studied using DFT calculations. The thermal stabilities of all dyes were evaluated by thermogravimetric analysis (TGA). The TGA data showed that all dyes were thermally stable up to 250 degrees C
Phenylazoindole dyes - Part I: The syntheses, characterizations, crystal structures, quantum chemical calculations and antimicrobial properties
No full textIn this study, the synthesis of four new phenylazo indole dyes (dye 1-4) were carried out by diazotization of 4-aminoacetophenone and coupling with various 2- and 1,2-disubstituted indole derivatives. The dyes were characterized by UV-vis, FT-IR, H-1 NMR, HRMS and X-ray single crystal diffraction methods. Azo-hydrazone tautomeric bahavior of the dyes in different solvents (DMSO, methanol, acetic acid and chloroform) was investigated by using H-1 NMR and UV-vis results. The experimental results were compared with the corresponding calculated values. The results of experimental data and theoretical calculations showed that the azo tautomer is more stable than hydrazone tautomer. In addition to this, the antimicrobial activity of the dyes was also evaluated. Published by Elsevier B.V
Phenylazoindole dyes 2: The molecular structure characterizations of new phenylazo indoles derived from 1,2-dimethylindole
No full textIn this study, five new phenylazo indoles derived from 1,2-dimethylindole were synthesized and characterized to evaluate the substituent effects on the molecular structures and absorption spectra. Theoretical calculations were carried out by density functional theory. The experimental and theoretical results are compared. X-ray single-crystal diffraction analyses reveal that the dyes have similar planar molecular conformation between azo and aromatic/heteroaromatic ring units but dissimilar crystal packing. The analysis of the electronic spectra showed that the electron-withdrawing groups (-Cl and -CN) were more effective than the electron-donating groups (-CH3 and -OCH3). Dyes containing electron-donating groups do not show significant changes relative to the parent dye, whereas the absorption maxima move to longer wavelengths for dyes containing electron-withdrawing groups. In addition, the absorption maxima exhibit the little bathochromic shifts for each dye with the increasing dielectric constants of the solvents. (C) 2013 Published by Elsevier Ltd
- …
