Photoluminescence of 1,3-Diphenyl-1H-pyrazolo[3,4-b]quinoline and its derivatives: Experiment and quantum chemical simulations
| Autor: | Ewa Gondek, Andriy V. Kityk, Andrzej Danel, B. Jarosz, Sylwia Całus |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Photoluminescence
Materials science Absorption spectroscopy business.industry Solvatochromism Quinoline Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials symbols.namesake chemistry.chemical_compound Optics chemistry Molecular vibration Excited state Stokes shift symbols Emission spectrum Electrical and Electronic Engineering Physical and Theoretical Chemistry business |
| Zdroj: | Optics Communications. 271:16-23 |
| ISSN: | 0030-4018 |
| DOI: | 10.1016/j.optcom.2006.10.010 |
| Popis: | The optical absorption and photoluminescent spectra are studied in recently synthesized diphenyl pyrazoloquinolines (DPPQ): 1,3-diphenyl-1 H -pyrazolo[3,4- b ] quinoline and its 6-vinyl, 6- N , N -diphenyl, 6-methyl, 6-fluoro, 6-bromo and 6-chloro derivatives. The photoemission spectra are recorded in organic solvents of different polarity and found to be highly solvatochromic. The measured spectra are compared with the quantum chemical calculations performed by means of the semiempirical methods (AM1 or PM3) in combination with the equilibrium molecular conformation (EMC) in vacuo ( T = 0 K, Γ = 0.12 eV) or MD simulations ( T = 300 K). The broadening of absorption and emission bands and their red-shift with increasing of temperature may be well reproduced by MD simulations. The Stokes shift of the photoluminescent spectra is obtained by including vibrational modes into the emission equation. The quantum chemical method AM1 in combination with MD simulations gives in most cases the best agreement with the experimental data. By comparing the emission spectra of 6- N , N -diphenyl-DPPQ with other DPPQ-derivatives one concludes that the molecular fragment diphenyl-amin [(C 6 H 5 ) 2 N–] is likely subjected to strong conformational changes in solvents. The large difference between the excited- and state-dipole moments indicates on a strong electron transfer effect being common for all DPPQ derivatives. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect