Using the mechanical bond to tune the performance of a thermally activated delayed fluorescence emitter**

Pachaiyappan Rajamalli, Federica Rizzi, Wenbo Li, Michael A. Jinks, Abhishek Kumar Gupta, Beth A. Laidlaw, Ifor D.W. Samuel*, Thomas J. Penfold*, Stephen M. Goldup*, Eli Zysman-Colman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)
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We report the characterization of rotaxanes based on a carbazole-benzophenone thermally activated delayed fluorescence luminophore. We find that the mechanical bond leads to an improvement in key photophysical properties of the emitter, notably an increase in photoluminescence quantum yield and a decrease in the energy difference between singlet and triplet states, as well as fine tuning of the emission wavelength, a feat that is difficult to achieve when using covalently bound substituents. Computational simulations, supported by X-ray crystallography, suggest that this tuning of properties occurs due to weak interactions between the axle and the macrocycle that are enforced by the mechanical bond. This work highlights the benefits of using the mechanical bond to refine existing luminophores, providing a new avenue for emitter optimization that can ultimately increase the performance of these molecules.

Original languageEnglish
Pages (from-to)12066-12073
Number of pages8
JournalAngewandte Chemie - International Edition
Issue number21
Early online date5 Mar 2021
Publication statusPublished - 17 May 2021

Bibliographical note

Funding Information:
P.R. acknowledges support from a Marie Skłodowska‐Curie Individual Fellowship (MCIF; No. 749557). E.Z.‐C. thanks the Leverhulme trust for support (RPG‐2016‐047). T.J.P. acknowledges the EPSRC (EP/P012388/1, EP/T022442/1) for support. E.Z.‐C. and I.D.W..S acknowledge support from EPSRC (EP/L017008, EP/P010482/1). SMG thanks the European Research Council (Consolidator Grant Agreement no. 724987) and the Leverhulme Trust (ORPG‐2733) for funding and the Royal Society for a Wolfson Research Fellowship. W.L. acknowledges support from China Scholarship Council (201708060003). The authors thank Drs Peter Horton and Graham Tizzard of the National Crystallographic Service for assistance with X‐ray diffraction analysis. A.K.G. is thankful to the Royal Society for Newton International Fellowship NF171163. We are also grateful for financial support from the University of St Andrews Restarting Research Funding Scheme (SARRF), which is funded through the Scottish Funding Council grant reference SFC/AN/08/020.

Publisher Copyright:
© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH


  • luminescence
  • mechanical bond
  • rotaxane
  • supramolecular chemistry
  • TADF

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry


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