Two-photon absorption of oxindole-based push–pull molecular motors

Ainoa Guinart, Daniel Doellerer, Daisy R.S. Pooler, John Y. de Boer, Sandra Doria, Laura Bussotti, Mariangela Di Donato*, Ben L. Feringa*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Future applications of light-driven molecular motors in bio-based systems and soft materials require their operation with benign, low-energy light irradiation. Here we report four rotary molecular motors based on oxindole units which can be driven by near-infrared light. By installing an electron-withdrawing CN group on the oxindole lower half, in direct conjugation through the alkene axle to the electron-donating OMe substituent on the upper half, our design establishes a rigid push–pull system which red-shifts the absorption maximum further into the visible region. We also show that the induced nonlinearity to the system increases their two-photon absorption cross section, and the operation of oxindole based molecular motors with 800 nm light for the very first time. The motors prepared in this work show improved performance compared to previous oxindole based motors, e.g. visible light addressability up to 530 nm and 1.5-fold increase in quantum yields in both directions, whilst retaining their desirable qualities of easy synthesis and fast rotation speed.

Original languageEnglish
Article number115649
Number of pages9
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume453
Early online date13-Apr-2024
DOIs
Publication statusE-pub ahead of print - 13-Apr-2024

Keywords

  • Molecular motors
  • Two photon absorption
  • Push–pull
  • Oxindole

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