Volume 26, Issue 57 p. 12987-12995
Full Paper

Resonance Assisted Hydrogen Bonding Phenomenon Unveiled through Both Experiments and Theory: A New Family of Ethyl N-Salicylideneglycinate Dyes

Dinara S. Shapenova

Dinara S. Shapenova

University of Tyumen, Volodarskogo Str.6, 625003 Tyumen, Russian Federation

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Alexey A. Shiryaev

Alexey A. Shiryaev

University of Tyumen, Volodarskogo Str.6, 625003 Tyumen, Russian Federation

West-Siberian Interregional Scientific and Educational Center, Russian Federation

Innovation Center for Chemical and Pharmaceutical Technologies, Ural Federal University named after the First President of Russia B.N. Eltsin, Mira Str. 19, 620002 Ekaterinburg, Russian Federation

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Michael Bolte

Michael Bolte

Institut für Anorganische Chemie, J.-W.-Goethe-Universität, 60323 Frankfurt am Main, Germany

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Mercedes Kukułka

Mercedes Kukułka

Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Cracow, Poland

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Dariusz W. Szczepanik

Dariusz W. Szczepanik

Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Cracow, Poland

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James Hooper

James Hooper

Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Cracow, Poland

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Maria G. Babashkina

Maria G. Babashkina

Independent Researcher, Respubliki Str. 14, 625003 Tyumen, Russian Federation

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Ghodrat Mahmoudi

Ghodrat Mahmoudi

Department of Chemistry, Faculty of Science, University of Maragheh, P.O. Box 55181–83111, Maragheh, Iran

Correction added on May 30, 2022, after first online publication: Author affiliations updated; an incorrect affiliation to the Institute of Condensed Matter and Nanosciences, Universite catholique de Louvain for Maria G. Babashkina and Damir A. Safin has been removed.

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Mariusz P. Mitoraj

Corresponding Author

Mariusz P. Mitoraj

Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Cracow, Poland

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Damir A. Safin

Corresponding Author

Damir A. Safin

University of Tyumen, Volodarskogo Str.6, 625003 Tyumen, Russian Federation

West-Siberian Interregional Scientific and Educational Center, Russian Federation

Innovation Center for Chemical and Pharmaceutical Technologies, Ural Federal University named after the First President of Russia B.N. Eltsin, Mira Str. 19, 620002 Ekaterinburg, Russian Federation

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First published: 19 May 2020
Citations: 18

Graphical Abstract

Photoluminescence and thermochromic properties of ethyl N-salicylideneglycinate dyes differing in donor–acceptor properties are driven by the well-established, in general chemistry, concept of π-electrons delocalization, that is, resonance assisted hydrogen bonding (RAHB), which is unveiled and deeply understood on the grounds of both experiment and theory.

Abstract

Extensive experimental and theoretical investigations are reported on the nature of resonance-assisted hydrogen bonding phenomenon (RAHB) and its influence on photophysical properties of the newly designed dyes differing in donor–acceptor properties, namely ethyl N-salicylideneglycinate (1), ethyl N-(5-methoxysalicylidene)glycinate (2), ethyl N-(5-bromosalicylidene)glycinate (3) and ethyl N-(5-nitrosalicylidene)glycinate (4). All compounds are thermochromic in the solid state and they contain a typical intramolecular O−H⋅⋅⋅N hydrogen bond formed between the hydroxyl hydrogen atom and the imine nitrogen atom, yielding the enol form in the solid state. It is unveiled, that the magnitude of RAHB effect fine tunes the strength of the O−H⋅⋅⋅N bonding and accordingly the relative populations of the enol, cis-keto and trans-keto forms leading to variation of the photophysical properties of 14. It is determined, that the electron-withdrawing NO2 in 4 amplifies the most RAHB effect causing the breaking of the O−H⋅⋅⋅N hydrogen bond and accordingly formation of the dominant cis-keto isomer in both the solid state and EtOH. To this end, the UV/Vis spectra of 13 in EtOH revealed the exclusive presence of the enol form, while the prevalent contribution of the cis-keto form was found for 4. Furthermore, only compound 4 is emissive in the solid state in ambient condition due to dual emission arising from the cis-keto* and trans-keto* forms, while 2 was found to be highly emissive in EtOH. It is revealed qualitatively and quantitatively, based on the ETS-NOCV charge and energy decomposition scheme and the EDDB population-based method, that RAHB is strongly a non-local phenomenon based on electrons pumping or sucking through both the π- and σ-channels, which accordingly exerts chemical bonding changes at both the phenyl ring and predominantly a distant O−H⋅⋅⋅N area.

Conflict of interest

The authors declare no conflict of interest.