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Published on: November 29, 2018
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Orthogonal Photoswitching with Norbornadiene
Martin Drøhse Kilde1, Line Broløs1, Mads Mansø1
1Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|May 21, 2020
Summary
This study demonstrates orthogonal photoswitching using the norbornadiene/quadricyclane (NBD/QC) system. Metal ion complexation allows for wavelength-controlled, sequential photoisomerization, enabling tunable multi-state systems.
Area of Science:
- Supramolecular Chemistry
- Photochemistry
- Materials Science
Background:
- Orthogonal photoswitching offers precise control over multiple functions via selective photoisomerization.
- The norbornadiene/quadricyclane (NBD/QC) system is a known photo/thermo-switch.
- Controlling the sequence of photoisomerization in such systems remains a challenge.
Purpose of the Study:
- To demonstrate orthogonal photoswitching using the NBD/QC system.
- To investigate the effect of metal ion coordination on NBD/QC optical and switching properties.
- To develop a multi-state system with tunable photoisomerization sequences.
Main Methods:
- Synthesis of pyridyl-ligated NBD/QC derivatives.
- Coordination of metal ions (PdII, AgI, PbII) to the ligands.
- Spectroscopic analysis (UV-Vis absorption) to study optical properties.
- Photoisomerization studies under varying irradiation wavelengths.
Main Results:
- Metal ion chelation, particularly with PdII, significantly alters NBD/QC optical and switching properties.
- A four-state system was achieved by mixing PdII complex with its free ligand.
- Orthogonal photoisomerization, controllable by irradiation wavelength, was demonstrated for complexed and uncomplexed NBD/QC species.
- Complexation with AgI and PbII also resulted in red-shifted NBD absorptions.
Conclusions:
- Metal ion coordination provides a powerful strategy to modulate the photoswitching behavior of NBD/QC systems.
- The developed system enables wavelength-selective and orthogonally controllable photoisomerization.
- This work opens avenues for designing sophisticated multi-state molecular switches and functional materials.
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