TY - JOUR

T1 - Photochemical protonation of an azahelicene in 1,2-dichloroethane

AU - Tamozhnikova, Veronica S.

AU - Grivin, Vjacheslav P.

AU - Tsentalovich, Yuri P.

AU - Yu. Balakhonov, Roman

AU - Mekeda, Igor S.

AU - Shirinian, Valerii Z.

AU - Glebov, Evgeni M.

N1 - Сведения о финансировании Финансирующий спонсор Номер финансирования Акроним Russian Science Foundation 23–13-00226

PY - 2025/2/1

Y1 - 2025/2/1

N2 - Heterocyclic analogues of phenanthridine are an important class of nitrogen-containing compounds with promising optical properties including high quantum yield of luminescence, high molar absorption coefficients and sensitivity to solvent medium. The luminescent properties of phenanthridine and its derivatives can be changed by introducing appropriate substituents into various positions of the phenanthridine framework. Recently developed luminescent azahelicenes of furoquinoline series demonstrate strong acidochromic effect both on absorption and emission spectra. One of the features of these compounds is the photochemical formation of a protonated form in chlorine-containing solvents under UV irradiation. In this work we perform a mechanistic study of 3-methoxy-6-(4-methoxyphenyl)naphtho[1′,2′:4,5]furo[2,3-c]quinoline (compound 1) in 1,2-dichloroethane (1,2-DCE) by means of stationary and laser flash photolysis. In addition to the triplet state formation observed in typical organic solvents photoexcitation in 1,2-DCE was found to result in an electron transfer from the excited compound 1 to a solvent molecule. Reactions of resulting intermediates lead to the formation of the protonated azahelicene. The quantitative mechanism of photoprotonation is put forward.

AB - Heterocyclic analogues of phenanthridine are an important class of nitrogen-containing compounds with promising optical properties including high quantum yield of luminescence, high molar absorption coefficients and sensitivity to solvent medium. The luminescent properties of phenanthridine and its derivatives can be changed by introducing appropriate substituents into various positions of the phenanthridine framework. Recently developed luminescent azahelicenes of furoquinoline series demonstrate strong acidochromic effect both on absorption and emission spectra. One of the features of these compounds is the photochemical formation of a protonated form in chlorine-containing solvents under UV irradiation. In this work we perform a mechanistic study of 3-methoxy-6-(4-methoxyphenyl)naphtho[1′,2′:4,5]furo[2,3-c]quinoline (compound 1) in 1,2-dichloroethane (1,2-DCE) by means of stationary and laser flash photolysis. In addition to the triplet state formation observed in typical organic solvents photoexcitation in 1,2-DCE was found to result in an electron transfer from the excited compound 1 to a solvent molecule. Reactions of resulting intermediates lead to the formation of the protonated azahelicene. The quantitative mechanism of photoprotonation is put forward.

KW - 1, 2-Dichloroethane

KW - Azahelicenes

KW - Intersystem crossing

KW - Laser flash photolysis

KW - Luminescence

KW - Photochemistry

KW - Photophysics

KW - Photoprotonation

KW - T-T absorption

KW - Time correlated photon counting

UR - https://www.mendeley.com/catalogue/79891c60-1522-3c60-9185-ad9ea5dac31e/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85207026279&origin=inward&txGid=581a5d29818f8f1c458a64b2b20f5430

U2 - 10.1016/j.jphotochem.2024.116106

DO - 10.1016/j.jphotochem.2024.116106

M3 - Article

VL - 459

JO - Journal of Photochemistry and Photobiology A: Chemistry

JF - Journal of Photochemistry and Photobiology A: Chemistry

SN - 1010-6030

M1 - 116106

ER -