Solvent Induced Helix Folding of Defined Indolenine Squaraine Oligomers

Turkin A, Holzapfel M, Agarwal M, Fischermeier D, Mitric R, Schweins R, Gröhn F, Lambert C (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Chemistry - A European Journal Wiley

DOI: 10.1002/chem.202101063

Abstract

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.

Authors with CRIS profile

Mohit Agarwal Interdisziplinäres Zentrum für Molekulare Materialien Franziska Gröhn Professur für Molekulare Nanostrukturen

Involved external institutions

Julius-Maximilians-Universität Würzburg DE Germany (DE) Institute Laue-Langevin (ILL) FR France (FR)

How to cite

APA:

Turkin, A., Holzapfel, M., Agarwal, M., Fischermeier, D., Mitric, R., Schweins, R.,... Lambert, C. (2021). Solvent Induced Helix Folding of Defined Indolenine Squaraine Oligomers. Chemistry - A European Journal. https://doi.org/10.1002/chem.202101063

MLA:

Turkin, Arthur, et al. "Solvent Induced Helix Folding of Defined Indolenine Squaraine Oligomers." Chemistry - A European Journal (2021).

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