Side-Chain Azobenzene Polymers: Synthesis and Photochemical Properties

International audienceA series of methacrylic monomers containing azobenzene moiety with alkyl spacer and different substituents is synthesized. Their photophysical and photochemical properties have been investigated. The photophysical properties of these compounds are investigated by 1H NMR, IR, and UV spectroscopies.</p

Optical properties of styrylquinoline containing copolymers withdifferent substituents

International audienceStyrylquinolines (StQs) are derivatives of stilbene and can undergo various photochemical reactions [1]. They have two activecentres: ethylene group and an endocyclic nitrogen atom. Styryl dyes [2], and styrilquinoline containing compounds were usedfor various sensitive materials, such as sensitizers or desensitizers. The development of new technologies leads to the discoveryof new applications for styrylquinoline dyes in the fields of electroluminescence [3], photochromism [4], and pharmacy [5]. Thestudy of the photochemical properties of 2-styrylquinoline and its several derivatives showed that substituents in the styrylmoiety increase the quantum efficiency of photoisomerization [6].The aim of the study was to present the influence of various substituents on luminescence and optical properties ofstyrylquinoline copolymers. The thin films of synthesized compounds were prepared using the spin-coating technique(Spin200i, POLOS) at a spin rate of 1500 rpm for 60 s. Immediately after the deposition, the films were cured in an oven at50ºC for 180 minutes in order to eliminate any residual solvent. Optical parameters were obtained from absorbancemeasurements. The luminescent properties of prepared thin layers on glass substrates were registered by the HITACHI f-2500fluorescence spectrophotometer in the range of 360-600 nm (λex. = 340 nm, Xe lamp).References:[1] E.N. Gulakova, D.V. Berdnikova, T.M. Aliyeu, Y.V. Fedorov, I.A. Godovikov, O.A. Fedorova, “Regiospecific C-N photocyclization of 2-styrylquinolines,” J. Org. Chem. 79, 5533–5537 (2014).[2] T. Deligeorgiev, A. Vasilev, S. Kaloyanova, J.J. Vaquero, “Styryl dyes – synthesis and applications during the last 15 years,” Soc. Dyers Col. 126, 55–80 (2010).[3] M. Rams-Baron, M. Dulski, A. Mrozek-Wilczkiewicz, M. Korzec, W. Cieslik, E. Spaczyńska, P. Bartczak, A. Ratuszna, J. Polanski, R. Musiol, “Synthesis of New Styrylquinoline Cellular Dyes, Fluorescent Properties, Cellular Localization and Cytotoxic Behavior,” PLoS ONE 10(6), 1-17 (2015).[4] M.F. Budyka, N.I. Potashova, T.N. Gavrishova, V.M. Li, “Design of fully photonic molecular logic gates based on the supramolecular bis-styrylquinoline dyad,” Nanotechnol. Russ. 7, 280–287 (2012).[5] F. Mao, J. Yan, J. Li, X. Jia, H. Miao, Y. Sun, L. Huang, X. Li, “New multi-target-directed small molecules against Alzheimer’s disease: a combination of resveratrol and clioquinol,” Org. Biomol. Chem. 12, 5936–5944 (2014).[6] M.F. Budyka, N.I. Potashova, T.N. Gavrishova, V.M. Li, “Photoisomerization of 2-styrylquinoline in neutral and protonated forms,” High Energy Chem. 42, 446–453 (2008)

Optical properties of styrylquinoline containing copolymers withdifferent substituents

International audienceStyrylquinolines (StQs) are derivatives of stilbene and can undergo various photochemical reactions [1]. They have two activecentres: ethylene group and an endocyclic nitrogen atom. Styryl dyes [2], and styrilquinoline containing compounds were usedfor various sensitive materials, such as sensitizers or desensitizers. The development of new technologies leads to the discoveryof new applications for styrylquinoline dyes in the fields of electroluminescence [3], photochromism [4], and pharmacy [5]. Thestudy of the photochemical properties of 2-styrylquinoline and its several derivatives showed that substituents in the styrylmoiety increase the quantum efficiency of photoisomerization [6].The aim of the study was to present the influence of various substituents on luminescence and optical properties ofstyrylquinoline copolymers. The thin films of synthesized compounds were prepared using the spin-coating technique(Spin200i, POLOS) at a spin rate of 1500 rpm for 60 s. Immediately after the deposition, the films were cured in an oven at50ºC for 180 minutes in order to eliminate any residual solvent. Optical parameters were obtained from absorbancemeasurements. The luminescent properties of prepared thin layers on glass substrates were registered by the HITACHI f-2500fluorescence spectrophotometer in the range of 360-600 nm (λex. = 340 nm, Xe lamp).References:[1] E.N. Gulakova, D.V. Berdnikova, T.M. Aliyeu, Y.V. Fedorov, I.A. Godovikov, O.A. Fedorova, “Regiospecific C-N photocyclization of 2-styrylquinolines,” J. Org. Chem. 79, 5533–5537 (2014).[2] T. Deligeorgiev, A. Vasilev, S. Kaloyanova, J.J. Vaquero, “Styryl dyes – synthesis and applications during the last 15 years,” Soc. Dyers Col. 126, 55–80 (2010).[3] M. Rams-Baron, M. Dulski, A. Mrozek-Wilczkiewicz, M. Korzec, W. Cieslik, E. Spaczyńska, P. Bartczak, A. Ratuszna, J. Polanski, R. Musiol, “Synthesis of New Styrylquinoline Cellular Dyes, Fluorescent Properties, Cellular Localization and Cytotoxic Behavior,” PLoS ONE 10(6), 1-17 (2015).[4] M.F. Budyka, N.I. Potashova, T.N. Gavrishova, V.M. Li, “Design of fully photonic molecular logic gates based on the supramolecular bis-styrylquinoline dyad,” Nanotechnol. Russ. 7, 280–287 (2012).[5] F. Mao, J. Yan, J. Li, X. Jia, H. Miao, Y. Sun, L. Huang, X. Li, “New multi-target-directed small molecules against Alzheimer’s disease: a combination of resveratrol and clioquinol,” Org. Biomol. Chem. 12, 5936–5944 (2014).[6] M.F. Budyka, N.I. Potashova, T.N. Gavrishova, V.M. Li, “Photoisomerization of 2-styrylquinoline in neutral and protonated forms,” High Energy Chem. 42, 446–453 (2008)

Effect of UV-Irradiation and ZnO Nanoparticles on Nonlinear Optical Response of Specific Photochromic Polymers

A series of methacrylic styrylquinoline polymers have been synthesized and characterized by spectroscopic and nonlinear optical (NLO) investigations. The NLO properties of studied polymer compounds in the form of thin films prepared by a spin coating method have been investigated by means of second and third harmonic generation via Maker fringe setup with a laser source at 1064 nm and a pulse duration of 30 ps. The results show strong second harmonic signal dependence on polarization configurations. This second harmonic generation (SHG) response was enhanced by UV-irradiation at 366 nm and doping by ZnO nanoparticles (NPs) (100 nm), while the opposite effect was achieved for a third harmonic generation experiment. Thus, values of second and third order nonlinear susceptibilities were determined by theoretical calculations based on comparative models. The remarkable NLO results presented in this paper expose potential optoelectronic and photonic applications

Effect of 2-Methylthiazole Group on Photoinduced Birefringence of Thiazole-Azo Dye Host&ndash;Guest Systems at Different Wavelengths of Irradiation

The photoinduced birefringence behaviors of host&ndash;guest systems based on heterocyclic thiazole&ndash;azo dyes with different substituents, dispersed into PMMA matrix, were investigated under three excitation wavelengths, i.e., 405 nm, 445 nm or 532 nm. The wavelengths fell on the blue side, near the maximum or on the red side of the absorption bands of trans-azo dyes, respectively. We found that photoinduced birefringence was generated at a similar extent in all studied systems, except the system containing a 2-methyl-5-benzothiazolyl as thiazole&ndash;azo dye substituent. For this material, the achieved birefringence value was the highest among the whole series, regardless of the excitation wavelength. Moreover, we identified the optimal irradiation wavelength for efficient birefringence generation and showed that large absorption of excitation light by trans isomer does not account for achieving a significant degree of molecular alignment. The obtained results indicate that thiazole&ndash;azo dye with a 2-methyl-5-benzothiazolyl substituent shows promising photoinduced birefringence, and can be considered a dye potentially suitable for optical applications

Spectroscopic Studies of Styrylquinoline Copolymers with Different Substituents

International audienceThe aim of the study was to present the influence of various styrylquinoline (StQ) substituents on the luminescence, structural, and optical properties of StQ-containing copolymers. StQ-containing copolymers were synthesized by free-radical thermoinitiated polymerization. The calculations of the copolymerization ratios for the obtained copolymers were based on the basis of the integrated peak areas of the 1H NMR spectra in CDCl3. The luminescence measurements show that the change in the nature of the electron-donating and electron-withdrawing of the substituent shifts the emission band to longer wavelengths and causes a transition from blue fluorescence to green or yellow and orange (or even white), regardless of the electronic nature of the introduced substituent group. The structural properties were measured by Fourier-Transform Infrared (FTIR) and Raman spectroscopies. For all of the compounds, we observed similarities in the bands in FTIR and Raman measurements. The optical parameters were obtained from the absorbance measurements. Additionally, Scanning Electron Microscopy (SEM) was used to study the surface topography of the thin layers on the glass substrate. The SEM images confirm that we obtained smoother layers for two copolymers. The computational Density Functional Theory (DFT) analysis fully supports the beneficial features of the analyzed systems for their applications in optoelectronic devices. Based on the obtained results, it can be concluded that all of the studied styrylquinolines are promising materials for applications in organic light-emitting diodes (OLEDs). However, COP1 with an OCH3 donor substituent possess a wider luminescence band, and its layer is smoother and more transparent