The effect of substituent position and solvent on thermal Z‒E isomerization of dihydroquinolylazotetrazole dyes: kinetic, thermodynamic, and spectral approaches

The effect of substituent position and solvent on thermal Z‒E isomerization of dihydroquinolylazotetrazole dyes: kinetic, thermodynamic, and spectral approaches Full article

Journal

Photochemical and Photobiological Sciences
ISSN: 1474-9092 , E-ISSN: 1474-905X

Output data

Year: 2024, Volume: 23, Number: 1, Pages: 177-187 Pages count : 11 DOI: 10.1007/s43630-023-00511-4

Authors

Golovina Galina V. ¹ , Egorov Anton E. ¹ , Khodot Evgenii N. ² , Kostyukov Alexey A. ¹ , Timokhina Elena N. ¹ , Astakhova Tatiana Yu. ¹ , Nekipelova Tatiana D. ¹

Affiliations

1	Emanuel Institute of Biochemical Physics RAS, Kosygin Str. 4, Moscow, 119334, Russia
2	Zelinsky Institute of Organic Chemistry RAS, Leninskii Pr. 47, Moscow, 119991, Russia

Kinetic and thermodynamic parameters have been investigated for the thermal Z‒E isomerization of dihydroquinolylazotetrazole dyes with alkyl substituents (Me, t-Bu, and Adm) at positions 1 (dyes 2) and 2 (dyes 3) of the tetrazole moiety in two solvents of different polarity, acetonitrile (MeCN) and toluene. The experimental results show crucial dependence of these parameters on a substituent position in the tetrazole moiety and on a solvent. For dyes 2, Eact and ΔH‡ are lower in MeCN than in toluene that results in a high increase in the lifetimes of the Z isomers: from milliseconds in MeCN to minutes in toluene. For dyes 3, the difference in Eact and ΔH‡ in the two solvents is opposite: Eact and ΔH‡ are by more than 20 kJ mol−1 higher in MeCN, nevertheless, the rate constants for 3 in toluene are comparable with those in MeCN at the ambient temperature and the difference in the behavior is determined by the value of negative entropy of activation. Quantum-chemical calculations of the thermal Z‒E isomerization show the possibility of the process to occur via crossing from the S0 to the thermally induced T1 state. The contribution of this path is highest for 3 in toluene. The analysis of the absorption spectra demonstrates that for the E isomers, the n‒π* and π‒π* transitions are within the long-wavelength absorption band and their positions relative each other are opposite in the solvents: the n‒π* transition is blue-shifted relative to the π‒π* transition in MeCN and is red-shifted in toluene.

Golovina G.V. , Egorov A.E. , Khodot E.N. , Kostyukov A.A. , Timokhina E.N. , Astakhova T.Y. , Nekipelova T.D.
The effect of substituent position and solvent on thermal Z‒E isomerization of dihydroquinolylazotetrazole dyes: kinetic, thermodynamic, and spectral approaches
Photochemical and Photobiological Sciences. 2024. V.23. N1. P.177-187. DOI: 10.1007/s43630-023-00511-4 WOS Scopus OpenAlex

Web of science:	WOS:001118775800002
Scopus:	2-s2.0-85178957284
OpenAlex:	W4389510008

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