Exciting Novel Polyaspartates: Design, Synthesis, and Photo-Responsive Behavior in Solution and Lyotropic Liquid Crystalline Phase Upon Irradiation with Visible Light.

Autor: Hossain R; Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Straße 16, 64287, Darmstadt, Germany., Thiele CM; Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Straße 16, 64287, Darmstadt, Germany.
Jazyk: angličtina
Zdroj: Macromolecular rapid communications [Macromol Rapid Commun] 2024 Nov; Vol. 45 (22), pp. e2400513. Date of Electronic Publication: 2024 Aug 20.
DOI: 10.1002/marc.202400513
Abstrakt: Many polypeptides form stable, helical secondary structures enabling the formation of lyotropic liquid crystalline (LLC) phases. Contrary to the well-studied polyglutamate, their counterparts based on polyaspartates exhibit a much lower helix inversion barrier. Therefore, the helix sense is not solely dictated by the chirality of the amino acid used, but additionally by the nature and conformation of the polymer sidechain. In this work, polymers responsive to irradiation with visible light are designed achieving conformational transitions from helix-to-coil and helix-to-helix. The synthesis and the application as LLC mesogens of several (co-)polyaspartates bearing ortho-fluorinated azobenzene (FAB) as a photochromic group are presented. Many of the obtained polymers undergo changes in their secondary structure upon E-Z-isomerization of the FAB-containing sidechain. Of special interest are copolymers that exhibit photo-responsive helix inversion without loss of their helical secondary structure. These copolymers form stable LLC phases in helicogenic solvents, where the effect of photo-switching on the macroscopic behavior is studied by NMR spectroscopy. Especially, the irradiation of the different LLC phases of the helix inversion polymers displays a change in the LLC order experienced by the solvent. These peculiar properties are promising for future applications as photo-responsive alignment media for structure elucidation in NMR.
(© 2024 The Author(s). Macromolecular Rapid Communications published by Wiley‐VCH GmbH.)
Databáze: MEDLINE
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