Synthesis, spectroscopic and TD-DFT quantum mechanical study of azo-azomethine dyes. A laser induced trans-cis-trans photoisomerization cycle.

Autor: Georgiev A; Department of Organic Chemistry, 1756 Sofia, 8 St. Kliment Ohridski Blvd, University of Chemical Technology and Metallurgy, Bulgaria. Electronic address: antonchem@abv.bg., Kostadinov A; Department of Organic Chemistry, 1756 Sofia, 8 St. Kliment Ohridski Blvd, University of Chemical Technology and Metallurgy, Bulgaria., Ivanov D; Department of Optical Metrology and Holography, Department of Optical Materials, 1113 Sofia, 109 'Acad. G. Bonchev' Blvd., Institute of Optical Materials and Technologies, Bulgarian Academy of Science, Bulgaria., Dimov D; Department of Optical Metrology and Holography, Department of Optical Materials, 1113 Sofia, 109 'Acad. G. Bonchev' Blvd., Institute of Optical Materials and Technologies, Bulgarian Academy of Science, Bulgaria., Stoyanov S; Laboratory of Structural Organic Analysis, Sofia 1113, 9 Acad. G. Bonchev Blvd., Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Science, Bulgaria., Nedelchev L; Department of Optical Metrology and Holography, Department of Optical Materials, 1113 Sofia, 109 'Acad. G. Bonchev' Blvd., Institute of Optical Materials and Technologies, Bulgarian Academy of Science, Bulgaria., Nazarova D; Department of Optical Metrology and Holography, Department of Optical Materials, 1113 Sofia, 109 'Acad. G. Bonchev' Blvd., Institute of Optical Materials and Technologies, Bulgarian Academy of Science, Bulgaria., Yancheva D; Laboratory of Structural Organic Analysis, Sofia 1113, 9 Acad. G. Bonchev Blvd., Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Science, Bulgaria.
Jazyk: angličtina
Zdroj: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy [Spectrochim Acta A Mol Biomol Spectrosc] 2018 Mar 05; Vol. 192, pp. 263-274. Date of Electronic Publication: 2017 Nov 07.
DOI: 10.1016/j.saa.2017.11.016
Abstrakt: This paper describes the synthesis, spectroscopic characterization and quantum mechanical calculations of three azo-azomethine dyes. The dyes were synthesized via condensation reaction between 4-(dimethylamino)benzaldehyde and three different 4-aminobenzene azo dyes. Quantum chemical calculations on the optimized molecular geometry and electron densities of the trans (E) and cis (Z) isomers and their vibrational frequencies have been computed by using DFT/B3LYP density-functional theory with 6-311++G(d,p) basis set in vacuo. The thermodynamic parameters such as total electronic energy E (RB3LYP), enthalpy H 298 (sum of electronic and thermal enthalpies), free Gibbs energy G 298 (sum of electronic and thermal free Gibbs energies) and dipole moment μ were computed for trans (E) and cis (Z) isomers in order to estimate the ΔE trans→cis , Δμ trans→cis, ΔH trans→cis , ΔG trans→cis and ΔS trans→cis values. After molecular geometry optimization the electronic spectra have been obtained by TD-DFT calculations at same basis set and correlated with the spectra of vapour deposited nanosized films of the dyes. The NBO analysis was performed in order to understand the intramolecular charge transfer and energy of resonance stabilization. Solvatochromism was investigated by UV-VIS spectroscopy in five different organic solvents with increasing polarity. The dynamic photoisomerization experiments have been performed in DMF by pump lasers λ=355nm (mostly E→Z) and λ=491nm (mostly Z→E) in spectral region 300nm - 800nm at equal concentrations and times of illumination in order to investigate the photodynamical trans-cis-trans properties of the CHN and NN chromophore groups of the dyes.
(Copyright © 2017 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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