Electrochemical and optical studies of new symmetrical and unsymmetrical imines with thiazole and thiophene moieties (original) (raw)
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Materials
In this paper, four new aromatic imines containing at least one thiazole-based heterocycle were analyzed in detail by UV–Vis spectroscopy, taking into consideration their chemical structures and interactions with PTB7, a known polymeric electron donor widely used in bulk heterojunction organic solar cells. It is demonstrated that the absorption spectra of the investigated active compositions can be modified not only by changing the chemical structure of imine, but also via formulations with PTB7. For all investigated imines and PTB7:imine compositions, calibration curves were obtained in order to find the optimum concentration in the composition with PTB7 for expansion and optimization of absorption spectra. All imines and PTB7:imine compositions were investigated in 1,2-dichlorobenzene by UV–Vis spectroscopy in various concentrations, monitoring the changes in the π–π* and n–π* transitions. With increasing imine concentrations, we did not observe changes in absorption maxima, while...
A new look at imines and their mixture with PC71BM for organic, flexible photovoltaics
Scientific Reports
Due to its high electron affinity and electron mobility in a wide absorption range of the visible solar spectrum, [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) is often used as an efficient acceptor in organic photovoltaics. In turn, imines are additives to the active layer of organic solar cells, mainly due to the free electron pair of the imine nitrogen atom and the presence of various chemical groups affecting the polarity and conformations of molecules. However, the attainable efficiency is not as high as expected. Therefore, we have systematically investigated two imines and their mixtures with PC71BM by spectroscopic (the high pressure UV–Vis and frequency domain dielectric), thermoelectric, and mechanical methods for organic, flexible photovoltaics. Both the imines, (N,NʹE,N,NʹE)-N,Nʹ-([2,2ʹ:5ʹ,2ʺ-terthiophene]-5,5ʺ-diylbis(methanylylidene))bis(benzo[d]thiazol-2-imine) (SC3) and (6E)-N-((5-(5-(5-((E)-(4-(4-(4-fluorophenyl)thiazol-2-yl)phenylimino)methyl)thiophen-2-yl)th...
Synthetic Metals, 2012
Low molecular weight compounds and polymers consisting of 1 and 2 thiophenes and double azomethine bonds prepared from hydrazine and thiophene aldehydes are presented. The effect of the number of thiophene rings on thermal, optical and electrochemical properties was examined. Polyazine with bithiophene structure exhibited slightly higher both glass transition temperature (T g = 121 • C) and the decomposition temperature (T 10 = 345 • C) than polymer with one thiophene ring in repeating unit (T g = 115 • C, T 10 = 321 • C). A higher degree of conjugation due to presence of bithiophene structure was confirmed by bathochromic shift of the absorbance and photoluminescence. Doping with HCl and FeCl 3 resulted in increase of fluorescence intensity. All the obtained compounds emitted blue light with the highest intensity both in solution and in solid state as a blend with PMMA. The investigated compounds exhibited electrochemical energy gap (E g ) in the range of 1.94-3.07 eV. Introduction of a second thiophene ring resulted in a decrease of E g by about 0.9 eV in the case of azines and 0.67 eV in polyazines. Additionally, energy band gap (E g ) was calculated theoretically at B3LYP/6-31G(d,p) level of theory.
Unsymmetrical and symmetrical azines toward application in organic photovoltaic
Optical Materials, 2015
The unsymmetrical and symmetrical azines prepared by condensation of benzophenone hydrazone with (di)aldehydes with thiophene rings were reported in this study The structures of obtained compounds were characterized by FTIR, 1 H NMR, and 13 C NMR spectroscopy as well as elemental analysis. Optical, electrochemical, and thermal properties of azines were investigated. The unsymmetrical azine with bithiophene unit exhibited liquid crystalline properties as was detected by DSC and POM experiments. All compounds are electrochemically active, however, only azines with bithiophene structure undergo reversible reduction process as was found in cyclic and differential pulse voltammetry (CV and DPV) studies. Additionally, the electronic properties, that is, orbital energies and resulting energy gap were calculated theoretically by density functional theory (DFT). The photovoltaic properties of two azines as active layer in organic solar cells at the configuration ITO/PEDOT:PSS/active layer/Al under an illumination of 1.3 mW/cm 2 were studied. Active cell layers blends of poly 3-hekxylthiophene (P3HT) or poly 3-butylthiophene (P3OT) with azines were applied. The device comprising P3HT with symmetrical azine containing bithiophene unit showed the highest value of power conversion efficiency (0.82%). To the best of our knowledge, the azines are very seldom considered as potential compounds in active layer in bulk heterojunction (BHJ) solar cells.
Journal of Applied Polymer Science, 2016
A new series of extended-conjugated and thermally stable thiophene-containing imine-linked polymers were synthesized via a Schiff-base condensation reaction between aryl aldehydes and 2,6-diaminopyridine building blocks. The backbones of the polymers were functionalized with phenyl, fluorosubstituted phenyl, thienyl, and pyridyl aromatic rings. The successful synthesis was confirmed with spectrochemical characterization techniques, including IR, 1 H-NMR, 13 C-NMR, and elemental analyses. The electronic properties of the polymers were investigated with ultraviolet-visible (UV-vis) absorption spectroscopy; the properties were collected experimentally and calculated with density functional theory (DFT) in the gas phase. The maximum absorption calculated from DFT was higher than the experimental values by about 60 nm; this was attributed to the absence of the solvent effect in the DFT case. The frontier molecular orbital ((HOMO) highest occupied molecular orbital and (LUMO) lowest unoccupied molecular orbital), optical band gap (E g ), and total energy (E T ) values of the optimized structures were calculated. Apparently, there was a significant relation between the number of thiophene rings and the resulting E g and E T values. As the number of thiophene rings in the polymer chain increased, E g and E T decreased, and the thermal stability of the polymers increased. E g and the absorption band edges were determined experimentally from the UV-vis and transmittance spectra, respectively. Poly(terthienyl-azomethine-pyridine-azomethine), with the highest thiophene content, had the lowest experimental and calculated E g values (2.10 and 2.63 eV, respectively). In contrast, upon fluorination, poly[(2,5dithienyl-1,4-difluorobenzene)-azomethine-pyridine-azomethine] exhibited the highest E g (2.81 eV) and absorption band edges (2.94 eV), whereas the thermal stability decreased to 250 8C.
The unsymmetrical and symmetrical azines prepared by condensation of benzophenone hydrazone with (di)aldehydes with thiophene rings were reported in this study The structures of obtained compounds were characterized by FTIR, 1 H NMR, and 13 C NMR spectroscopy as well as elemental analysis. Optical, electrochemical, and thermal properties of azines were investigated. The unsymmetrical azine with bithiophene unit exhibited liquid crystalline properties as was detected by DSC and POM experiments. All compounds are electrochemically active, however, only azines with bithiophene structure undergo reversible reduction process as was found in cyclic and differential pulse voltammetry (CV and DPV) studies. Additionally, the electronic properties, that is, orbital energies and resulting energy gap were calculated theoretically by density functional theory (DFT). The photovoltaic properties of two azines as active layer in organic solar cells at the configuration ITO/PEDOT:PSS/active layer/Al under an illumination of 1.3 mW/cm 2 were studied. Active cell layers blends of poly 3-hekxylthiophene (P3HT) or poly 3-butylthiophene (P3OT) with azines were applied. The device comprising P3HT with symmetrical azine containing bithiophene unit showed the highest value of power conversion efficiency (0.82%). To the best of our knowledge, the azines are very seldom considered as potential compounds in active layer in bulk heterojunction (BHJ) solar cells.
THE SYNTHESIS OF CONJUGATED IMINE DERIVATIVE COMPOUNDS AS POTENTIAL OLED COMPOUND PRECURSORS
OLED is a kind of semiconductor which utilizes organic compounds as the emissive layer. The organic compounds usually posses conjugated double bonds system. In this research, two imine derivative compounds have been successfully synthesized. Compound 1, 2,2'-(1E,1'E)-(1,2-phenylenebis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)diphenol, is yellow with chemical yields of 94.27% and melting point of 165 o C. Fluorescence spectroscopy measurement shows fluorescence with a wavelength of 546 nm which is consistent with green color. Mass spectroscopy (ESI-MS) measurement shows [M+H] + m/z peak 317.1292. Infrared spectroscopy measurement revealed C=N vibration wavenumber at 1612.7 cm -1 which is confirmed by the result of the 1 H NMR measurement that shows N=C-H chemical shift at 8.89 ppm and 13 C NMR for imine carbon at 165.68 ppm. Compound 2, (2E,2'E)-2,2'-(1E,1'E)-(1,2-phenylenebis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)bis(2,1-phenylene)bis(3-phenylacryl...
Journal of Molecular Structure, 2018
In present work, Polarization, Excited States, FT-IR, 1 H, 13 C NMR, Trans-Cis (E→Z) Isomerization Properties and Anisotropy of Thermal and Electrical Conductivity of the three new Azomethines dyes such as: 4-((E)-((4-((E)-phenyldiazenyl)phenyl)imino)methyl)benzoic acid (I), 5-phenyl-N-(pyrimidin-2-yl)isoxazole-3-carboxamide (II) and (Z)-1-(4-((E)-((4-phenylcyclopenta-1,4-dien-1-yl)methylene)amino)phenyl)ethanone oxime (III) in the presence of polyvinyl alcohol (PVA) matrix were studied. The absorption spectrum of the I, II and III in dimethylformamide (DMF) solution was calculated. The nature of absorption peaks of the dyes in the UV/Vis spectral regions was interpreted. The molecular HOMO-LUMO, excitation energies and oscillator strengths for E and Z isomers of the I, II and III have also been calculated and presented. Optical Properties of the PVA-films containing these new synthesized dyes have investigated. Polarizing Efficiency (PE) of obtained PVA-film is 97-98 % at Stretching Degree (R s) 3.5. Anisotropy of thermal and electrical conductivity of the PVA-films containing the title compounds was also measured and discussed.
Thiophene-centered azomethines: Structure, photophysical and electronic properties
Journal of Molecular Structure, 2020
We present the synthesis and structure characterization of three novel symmetrical azomethines 3a-c derived from 2,5-diamino-thiophene-3,4-dicarbonitrile together with the unexpected by-product 4 containing the saturated hemiaminal type bond. Photophysical properties (UVeVis and photoluminiscence) are shown to be affected mainly by the central thiophene unit with no influence from the type of linkage e unsaturated imine (-HC]N-) bond in 3a-c vs. the saturated hydroxymethylamino circuit [eHNeC(OH)H-] in 4. For the first time the electronic properties, such as distribution of the frontier molecular orbitals and resulting energy gaps, for compounds 3b,c and 4 are calculated by means of density functional theory methods and confirmed by an immediate experimental method-the energy-resolved electrochemical impedance spectroscopy.