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Cis-trans isomerisation of substituted aromatic imines a comparative experimental and theoretical study

  • The cis-trans isomerisation of N-benzylideneaniline (NBA) and derivatives containing a central C=N bond has been investigated experimentally and theoretically. Eight different NBA molecules in three different solvents were irradiated to enforce a photochemical trans (hv) -> cis isomerisation and the kinetics of the thermal backreaction cis (Delta)-> trans were determined by NMR spectroscopy measurements in the temperature range between 193 and 288 K. Theoretical calculations using density functional theory and Eyring transition-state theory were carried out for 12 different NBA species in the gas phase and three different solvents to compute thermal isomerisation rates of the thermal back reaction. While the computed absolute rates are too large, they reveal and explain experimental trends. Time-dependent density functional theory provides optical spectra for vertical transitions and excitation energy differences between trans and cis forms. Together with isomerisation rates, the latter can be used to identify "optimal switches" withThe cis-trans isomerisation of N-benzylideneaniline (NBA) and derivatives containing a central C=N bond has been investigated experimentally and theoretically. Eight different NBA molecules in three different solvents were irradiated to enforce a photochemical trans (hv) -> cis isomerisation and the kinetics of the thermal backreaction cis (Delta)-> trans were determined by NMR spectroscopy measurements in the temperature range between 193 and 288 K. Theoretical calculations using density functional theory and Eyring transition-state theory were carried out for 12 different NBA species in the gas phase and three different solvents to compute thermal isomerisation rates of the thermal back reaction. While the computed absolute rates are too large, they reveal and explain experimental trends. Time-dependent density functional theory provides optical spectra for vertical transitions and excitation energy differences between trans and cis forms. Together with isomerisation rates, the latter can be used to identify "optimal switches" with good photochromicity and reasonable thermal stability.show moreshow less

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Metadaten
Author:Ying Luo, Manuel Utecht, Jadranka Dokic, Sergey Korchak, Hans-Martin Vieth, Rainer Haag, Peter SaalfrankORCiDGND
DOI:https://doi.org/10.1002/cphc.201100179
ISSN:1439-4235 (print)
Parent Title (English):ChemPhysChem : a European journal of chemical physics and physical chemistry
Publisher:Wiley-VCH
Place of publication:Weinheim
Document Type:Article
Language:English
Year of first Publication:2011
Year of Completion:2011
Release Date:2017/03/26
Tag:density functional calculations; imines; isomerization; photochemistry; thermochemistry
Volume:12
Issue:12
Pagenumber:11
First Page:2311
Last Page:2321
Funder:Deutsche Forschungsgemeinschaft [SFB 658, C2, B7]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie
Peer Review:Referiert