TY - JOUR

T1 - Intramolecular interactions and optical properties of indole-containing alkaloids extracted from Arundo donax L.

AU - Zhalolov, Ikbol

AU - Urmonov, Dadahon

AU - Ibragimov, Alidjan

AU - Benassi, Enrico

N1 - Computational resources were kindly provided by the HPCC at Nazarbayev University.

PY - 2024/6/1

Y1 - 2024/6/1

N2 - Three optically active natural alkaloids were computationally investigated. The electronic ground state was found to be characterised by numerous intramolecular interactions, among which a hydrogen bond. These interactions are responsible for the different rate constants of the kinetics of conversion from one atropisomer to the other. The complex molecular electrostatic potential reveals a strong polar nature of these compounds, which strengthens when the electronic excited states are populated. The absorption spectra were interpreted and the intramolecular charge transfer nature of the Sn ← S0 transitions was revealed. The ECD spectra for the different atropisomers of these compounds indicate that the assignment proposed in the literature for 1 should be revised. The geometry of the excited state shows dramatic changes with respect to the ground state; some intramolecular interactions get lost. The fluorescence spectrum, proposed for the first time, shows de-excitation energies in the blue-green region (488 nm to 518 nm). Internal Conversion and intramolecular Electronic Energy Transfer may be fluorescence quenching channels.

AB - Three optically active natural alkaloids were computationally investigated. The electronic ground state was found to be characterised by numerous intramolecular interactions, among which a hydrogen bond. These interactions are responsible for the different rate constants of the kinetics of conversion from one atropisomer to the other. The complex molecular electrostatic potential reveals a strong polar nature of these compounds, which strengthens when the electronic excited states are populated. The absorption spectra were interpreted and the intramolecular charge transfer nature of the Sn ← S0 transitions was revealed. The ECD spectra for the different atropisomers of these compounds indicate that the assignment proposed in the literature for 1 should be revised. The geometry of the excited state shows dramatic changes with respect to the ground state; some intramolecular interactions get lost. The fluorescence spectrum, proposed for the first time, shows de-excitation energies in the blue-green region (488 nm to 518 nm). Internal Conversion and intramolecular Electronic Energy Transfer may be fluorescence quenching channels.

KW - Alkaloids

KW - Arundo donax L.

KW - Atropisomers

KW - Indole derivatives

KW - Intramolecular electronic energy transfer

KW - Molecular topology

KW - Optical and chiro-optical properties

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85185402897&origin=inward&txGid=bacf64b7dc54d3109cdc883bc84f99bc

UR - https://www.mendeley.com/catalogue/d7f8ed7c-f59a-3731-a1ab-f052ec464495/

U2 - 10.1016/j.jphotochem.2024.115524

DO - 10.1016/j.jphotochem.2024.115524

M3 - Article

VL - 451

JO - Journal of Photochemistry and Photobiology A: Chemistry

JF - Journal of Photochemistry and Photobiology A: Chemistry

SN - 1010-6030

M1 - 115524

ER -