| Abstract [eng] |
The aim of this research was to model and synthesize new indole[3,2-b]carbazole derivatives with different phenylethenyl- fragments and to investigate their thermal, optical, photophysical and electrochemical properties. Using Buchwald-Hartwig reactions, the compounds were synthesized by coupling one or two triphenylethenyl-, tetraphenylethenyl-, triphenylnytrylethenyl- residues to the central 12-pentyl-5,11dihydroindolo[3,2-b]carbazole moiety. The structures of the compounds were identified by nuclear magnetic resonance spectroscopy. Thermal properties of synthesized compounds were measured using thermogravimetric analysis and differential scanning calorimetry methods. It has been found that all synthesized compounds have high thermal stability, with a 5 % temperature loss in the range of 366–470 °C. Indole[3,2-b]carbazole derivatives with two phenylethenyl- moieties are more thermally stable than the compounds that have only one phenylethenyl- moiety. All these compounds form molecular glasses and their glass transition temperatures varies from 75 to 143 °C. Compounds containing two phenylethenyl- moieties have higher glass transition temperatures than the compounds that have only one phenylethenyl- moiety. The glass of the compound with one triphenylnytrylethenyl- moiety was unstable, the crystallization was observed at 216 °C. The solutions of synthesized compounds diluted in tetrahydrofuran were measured using ultraviolet spectroscopy method. The synthesized compounds that have tri/tetraphenylethenyl moieties absorbs radiation up to ~ 430 nm. Compounds containing triphenylnytrylethenyl- moieties absorbs radiation up to ~ 470 nm. Emission spectra of compounds diluted solutions and their layers were recorded using fluorescence spectroscopy method. The solutions of synthesized compounds diluted in dimethylformamide fluorescence peaks were recorded at the 390–694 nm wavelength, solutions diluted in tetrahydrofuran at the 420–683 nm and solutions diluted in toluene at the 415–598 nm wavelength. Fluorescence spectra of compounds layers formed by solution casting have one broad band and their peaks are in the wavelength range of 471–583 nm. Fluorescence quantum yields of solution of triphenylethenyl- compounds diluted in tetrahydrofuran are 35–43 %, and layers quantum yields had reduced 4–5 times (9 %). The values of quantum yields of compounds, that have tetraphenylethenyl- and triphenylethenyl- moieties, diluted solutions in tetrahydrofuran were lower than 1% and quantum yields of layers were 20–30 times higher (23–35 %). This increase is explained by the effect of aggregation induced emission. The values of synthesized compounds ionization potentials of dichloromethane solutions were measured using the cyclic voltammetry method and are in the range of 5.13–5.26 eV. The values of the electron affinity energy are in the range of –2.59– –2.24 eV. The synthesized compounds are electrochemically stable. Ionization potential of layers were measured using the electron photoemission in air method. The values vary between 5.48 to 5.65 eV. It has been found that the ionization potential values of compounds with two phenylethenyl- moieties are higher than those of compounds that have only one phenylethenyl- moiety. |
