Solvent Induced Helix Folding of Defined Indolenine Squaraine Oligomers

Please always quote using this URN: urn:nbn:de:bvb:20-opus-256869
  • A protecting group strategy was employed to synthesise a series of indolenine squaraine dye oligomers up to the nonamer. The longer oligomers show a distinct solvent dependence of the absorption spectra, that is, either a strong blue shift or a strong red shift of the lowest energy bands in the near infrared spectral region. This behaviour is explained by exciton coupling theory as being due to H- or J-type coupling of transition moments. The H-type coupling is a consequence of a helix folding in solvents with a small Hansen dispersity index.A protecting group strategy was employed to synthesise a series of indolenine squaraine dye oligomers up to the nonamer. The longer oligomers show a distinct solvent dependence of the absorption spectra, that is, either a strong blue shift or a strong red shift of the lowest energy bands in the near infrared spectral region. This behaviour is explained by exciton coupling theory as being due to H- or J-type coupling of transition moments. The H-type coupling is a consequence of a helix folding in solvents with a small Hansen dispersity index. DOSY NMR, small angle neutron scattering (SANS), quantum chemical and force field calculations agree upon a helix structure with an unusually large pitch and open voids that are filled with solvent molecules, thereby forming a kind of clathrate. The thermodynamic parameters of the folding process were determined by temperature dependent optical absorption spectra.show moreshow less

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Metadaten
Author: Arthur Turkin, Marco Holzapfel, Mohit Agarwal, David Fischermeier, Roland Mitric, Ralf Schweins, Franziska Gröhns, Christoph LambertORCiD
URN:urn:nbn:de:bvb:20-opus-256869
Document Type:Journal article
Faculties:Fakultät für Chemie und Pharmazie / Institut für Organische Chemie
Fakultät für Chemie und Pharmazie / Institut für Physikalische und Theoretische Chemie
Language:English
Parent Title (English):Chemistry—A European Journal
Year of Completion:2021
Volume:27
Issue:32
Pagenumber:8380–8389
Source:Chemistry—A European Journal 2021, 27(32):8380–8389. DOI: 10.1002/chem.202101063
DOI:https://doi.org/10.1002/chem.202101063
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 547 Organische Chemie
Tag:UV/Vis spectroscopy; dye chemistry; solvent effects; superstructure; supramolecular folding
Release Date:2022/03/08
EU-Project number / Contract (GA) number:654000
OpenAIRE:OpenAIRE
Licence (German):License LogoCC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International