DUAL EMISSION OF 2-AMINO-4-METHYLPYRIMIDINE: A THEORETICAL STUDY
| Autor: | Mark B. Bushuev, Viktor P. Krivopalov, Elena B. Nikolaenkova, Katerina A. Vinogradova, Nikita A. Shekhovtsov |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Photoluminescence Absorption spectroscopy Relaxation (NMR) 010402 general chemistry 010403 inorganic & nuclear chemistry 01 natural sciences Fluorescence 0104 chemical sciences Inorganic Chemistry Crystallography Excited state Materials Chemistry Molecule Emission spectrum Singlet state Physical and Theoretical Chemistry |
| Zdroj: | Journal of Structural Chemistry. 61:1521-1529 |
| ISSN: | 1573-8779 0022-4766 |
| DOI: | 10.1134/s0022476620100042 |
| Popis: | DFT and TD-DFT calculations at the B3LYP/LANL2DZ level of theory are performed in order to explain the origins of dual fluorescence and uncover the relaxation pathways of 2-amino-4-methylpyrimidine (L). The computations are in good agreement with experimental data. A high-energy emission band in the photoluminescence spectrum of 2-amino-4-methylpyrimidine (λmax = 350 nm) is related to the fluorescence of monomer L. Comparison of calculated and experimental IR and absorption spectra reveals that in the solid state L molecules form supramolecular {N–H···N}n hydrogen bonded associates. The formation of such associates favors the excited state double proton transfer (ESDPT). Calculated 2D potential energy curves for the ground and first singlet excited states of dimeric associates L2 indicate the presence of two stable forms, L2-amino and L2-imino. The low-energy band in the emission spectrum of 2-amino-4-methylpyrimidine (λmax = 445 nm) is probably associated with the fluorescence of the L2-imino form. Both fluorescence bands have a mixed π–π*, n–π* character as is evidenced by frontier orbitals involved in S1–S0 transitions. |
| Databáze: | OpenAIRE |
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