Light-driven reversible ring contraction and expansion to modulate strain, conformation, and reactivity

Chem, vol. 12, pp. 102947

Abstract

Chemists utilize cyclic constraints in molecules to control conformation, shape, and reactivity. The strain introduced in the (macro)cycles is released during reactions and drives transformations ranging from strain-promoted in vivo ligation to ring-opening metathesis polymerization. However, in each case, the ring size needs careful optimization and cannot be (re)adjusted. For remote optical modulation of strain, we designed looped diarylethene photoswitches that undergo reversible ring contraction/expansion upon electrocyclic ring closure/opening. Investigating a homologous series, we discovered that the long-wavelength absorption of the closed isomer serves as a diagnostic tool for stored molecular strain. By incorporating an internal allene reactive group in the loop, we enhanced its reactivity in a [3+2] dipolar cycloaddition with ethyl diazoacetate under visible light. Quantum chemical calculations helped rationalize the experimentally observed size-dependent photochemistry and reactivity of the macrocycles. Our approach opens opportunities for optical spatiotemporal reactivity control in life and materials science applications.

Authors 9

1. Tom Bösking Aachen DWI - Leibniz Institute for Interactive Materials Institute of Technical and Macromolecular Chemistry

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany

   Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany

2. Denise Schwarz Aachen Institute of Physical Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, Melatener Str. 20, 52074 Aachen, Germany

3. Daniel Aßenmacher Aachen DWI - Leibniz Institute for Interactive Materials Institute of Technical and Macromolecular Chemistry

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany

   Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany

4. Oliver Fiukowski Aachen DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials

   Affiliation as printed

   DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany

5. Michael Pohl Aachen DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials

   Affiliation as printed

   DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany

6. Mike Pauls Aachen Institute of Physical Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, Melatener Str. 20, 52074 Aachen, Germany

7. Christoph Bannwarth corresponding Aachen Institute of Physical Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, Melatener Str. 20, 52074 Aachen, Germany

8. Dušan Kolarski corresponding Aachen DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials · Max Planck Institute for Multidisciplinary Sciences

   Affiliation as printed

   DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany

   Max Planck Institute for Multidisciplinary Sciences, NanoBioPhotonics, Am Faßberg 11, 37077 Göttingen, Germany

9. Stefan Hecht corresponding Aachen DWI - Leibniz Institute for Interactive Materials Institute of Technical and Macromolecular Chemistry

   Humboldt-Universität zu Berlin · DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Center for the Science of Materials Berlin, Humboldt-Universität zu Berlin, Zum Großen Windkanal 2, 12489 Berlin, Germany

   DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany

   Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany

   Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany