Site Selectivity of Peptoids as Azobenzene Scaffold for Molecular Solar Thermal Energy Storage

Benjamin Tassignon; Zhihang Wang; Agostino Galanti; Julien De Winter; Paolo Samorì; Jérôme Cornil; Kasper Moth-Poulsen; Pascal Gerbaux

doi:10.1002/chem.202303168

Site Selectivity of Peptoids as Azobenzene Scaffold for Molecular Solar Thermal Energy Storage

Chemistry. 2023 Dec 14;29(70):e202303168. doi: 10.1002/chem.202303168. Epub 2023 Oct 25.

Authors

Benjamin Tassignon^{1

2}, Zhihang Wang^{3

4}, Agostino Galanti⁵, Julien De Winter¹, Paolo Samorì⁵, Jérôme Cornil², Kasper Moth-Poulsen^{3

6

7

8}, Pascal Gerbaux¹

Affiliations

¹ Organic Synthesis and Mass Spectrometry Laboratory (S2MOs), Chemistry Department, Materials Research Institute, University of Mons, Place du Parc 23, 7000, Mons, Belgium.
² Laboratory for Chemistry of Novel Materials, Chemistry Department, Materials Research Institute, University of Mons, Place du Parc 23, 7000, Mons, Belgium.
³ Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigârden, 4, 41296, Gothenburg, Sweden.
⁴ Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Rd, Cambridge, CB3 0FS, UK.
⁵ University of Strasbourg, CNRS, ISIS UMR 7006, 8 Allée Gaspard Monge, F-67000, Strasbourg, France.
⁶ The Institute of Materials Science of Barcelona ICMAB-CSIC, Bellaterra, 08193, Barcelona, Spain.
⁷ Catalan Institution for Research & Advanced Studies ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain.
⁸ Department of Chemical Engineering, Universitat Politècnica de Catalunya, EEBE, Eduard Maristany 10-14, 08019, Barcelona, Spain.

PMID: 37796081
DOI: 10.1002/chem.202303168

Abstract

Storing solar energy is a key challenge in modern science. MOlecular Solar Thermal (MOST) systems, in particular those based on azobenzene switches, have received great interest in the last decades. The energy storage properties of azobenzene (t_1/2 <4 days; ΔH~270 kJ/kg) must be improved for future applications. Herein, we introduce peptoids as programmable supramolecular scaffolds to improve the energy storage properties of azobenzene-based MOST systems. We demonstrate with 3-unit peptoids bearing a single azobenzene chromophore that dynamics of the MOST systems can be tuned depending on the anchoring position of the photochromic unit on the macromolecular backbone. We measured a remarkable increase of the half-life of the metastable form up to 14 days at 20 °C for a specific anchoring site, significantly higher than the isolated azobenzene moiety, thus opening new perspectives for MOST development. We also highlight that liquid chromatography coupled to mass spectrometry does not only enable to monitor the different stereoisomers during the photoisomerization process as traditionally done, but also allows to determine the thermal back-isomerization kinetics.

Keywords: MOST; azobenzene; peptoid; photoswitch; solar energy storage.