Abstract: 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 (lambda(max) = 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 center dot center dot center dot 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 L-2 indicate the presence of two stable forms, L-2-amino and L-2-imino. The low-energy band in the emission spectrum of 2-amino-4-methylpyrimidine (lambda(max) = 445 nm) is probably associated with the fluorescence of the L-2-imino form. Both fluorescence bands have a mixed pi-pi*, n-pi* character as is evidenced by frontier orbitals involved in S-1-S-0 transitions.

Cite: Shekhovtsov N.A. , Vinogradova K.A. , Nikolaenkova E.B. , Krivopalov V.P. , Bushuev M.B.
DUAL EMISSION OF 2-AMINO-4-METHYLPYRIMIDINE: A THEORETICAL STUDY
Journal of Structural Chemistry. 2020. V.61. N10. P.1521-1529. DOI: 10.1134/S0022476620100042 WOS Scopus РИНЦ

ArticleLinkType.TRANSLATED_TO_ORIGINAL: Шеховцов Н.А. , Виноградова Е.А. , Николаенкова Е.Б. , Кривопалов В.П. , Бушуев М.Б.
Двойная эмиссия 2-амино-4-метилпиримидина: теоретическое исследование
Журнал структурной химии (J STRUCT CHEM+). 2020. Т.61. №10. С.1605-1613. DOI: 10.26902/JSC_id61806 РИНЦ

Dates:

Published print:	Oct 1, 2020
Published online:	Oct 13, 2020

Identifiers:

Web of science	WOS:000598775100004
Scopus	2-s2.0-85106854873
Elibrary	46812554
OpenAlex	W3112839180

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