Photochemical Spin‐State Switching of an All‐Organic Molecular System with Visible Light

J Joël Schlecht (Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, Freiburg 79104, Germany) T Thomas Lohmiller P Philipp Thielert (Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany) C Clara Douglas (Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, Freiburg 79104, Germany) M Malte Gather (Department of Chemistry and Biochemistry University of Cologne Greinstrasse 4 50939 Cologne Germany) S Sabine Richert (Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany) O Oliver Dumele (Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, Freiburg 79104, Germany)

Abstract

Abstract Controlling the spin state of a molecule using the spatiotemporal properties of visible light is of interest for spintronic devices in information technology or (bio)medical applications. We, herein, report an all‐organic visible light‐induced photochromic system than can switch from a diamagnetic (singlet) to a paramagnetic (triplet) state. This is realized by precisely tuning orbital symmetry and internal molecular strain in a [5]helicene scaffold substituted with an indanedione π‐acceptor. Irradiation with visible light at cryogenic temperatures gives a kinetically meta‐stable paramagnetic diradical state with a solvent‐dependent ground‐state multiplicity (triplet or singlet), which can be thermally switched back to its initial diamagnetic state.

Article Details

Volume / Issue Vol. 64, Issue 46
Published November 10, 2025
ISSN 1433-7851
Publisher Wiley

Journal Info

Angewandte Chemie International Edition

Wiley

ISSN: 1433-7851 Physical Sciences

Authors (7)

J

Joël Schlecht

Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, Freiburg 79104, Germany

T

Thomas Lohmiller

P

Philipp Thielert

Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany

C

Clara Douglas

Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, Freiburg 79104, Germany

M

Malte Gather

Department of Chemistry and Biochemistry University of Cologne Greinstrasse 4 50939 Cologne Germany

S

Sabine Richert

Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany

O

Oliver Dumele

Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, Freiburg 79104, Germany