Institution: | 1. University of Tyumen, Volodarskogo Str.6, 625003 Tyumen, Russian Federation;2. 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;3. Institut für Anorganische Chemie, J.-W.-Goethe-Universität, 60323 Frankfurt am Main, Germany;4. Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Cracow, Poland;5. Independent Researcher, Respubliki Str. 14, 625003 Tyumen, Russian Federation;6. 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;7. 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. |
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 1 – 4 . 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 1 – 3 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. |