University of Groningen
Donor-Acceptor Stenhouse Adducts
Lerch, Michael Markus
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date: 2018
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Lerch, M. M. (2018). Donor-Acceptor Stenhouse Adducts. Rijksuniversiteit Groningen.
Copyright
Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum.
iii
Donor–Acceptor Stenhouse Adducts
First edition, June 2018
The work described in this thesis was carried out at the Stratingh Institute for Chemistry, University of Groningen, Groningen, The Netherlands.
This work was financially supported by the Netherlands Organization for Scientific Research (NWO-CW; TOP Grant NWO) and Laserlab-Europe (LENS002289).
Cover art and photographs by Rita M. Lerch-Heer
Printed by Ipskamp Drukkers BV, Enschede, The Netherlands ISBN: 978-94-034-0565-0 (Printed Version)
v
Donor–Acceptor Stenhouse Adducts
PhD thesis
to obtain the degree of PhD at the University of Groningen
on the authority of the Rector Magnificus Prof. E. Sterken
and in accordance with the decision by the College of Deans. This thesis will be defended in public on
Friday 1 June 2018 at 16:15 hours
by
Michael Markus Lerch
born on 15 February 1989 in Brittnau (AG), Switzerland
Supervisors Prof. dr. B.L. Feringa Prof. dr. W.R. Browne Co-supervisor Dr. W.C. Szymański Assessment committee Prof. dr. S.R. Meech Prof. dr. S. Otto
Prof. dr. E.J.R. Sudhölter
Paranymphs D. Dunkelmann Dr. L. Pfeifer
vii
Donor–Acceptor Stenhouse Adducts
Proefschrift
ter verkrijging van de graad van doctor aan de Rijksuniversiteit Groningen
op gezag van de
rector magnificus prof. Dr. E. Sterken en volgens besluit van het College voor Promoties.
De openbare verdediging zal plaatsvinden op vrijdag 1 juni 2018 om 16:15 uur
door
Michael Markus Lerch
geboren op 15 februari 1989 te Brittnau (AG), Zwitserland
Promotores Prof. dr. B.L. Feringa Prof. dr. W.R. Browne Copromotor Dr. W.C. Szymański Beoordelingscommissie Prof. dr. S.R. Meech Prof. dr. S. Otto
Prof. dr. E.J.R. Sudhölter
Paranimfen D. Dunkelmann Dr. L. Pfeifer
ix
This work is dedicated to Rita & Erich, Thomas and Lilian and to all the giants on whose shoulders we stand, including Ben, who – with his trust and willingness to let us explore any possible untrodden paths – has enabled this work.
xi
I
Chapter 1
The (Photo)chemistry of Stenhouse Photoswitches: Guiding Principles and System Design 1
1.1 Introduction 2
1.1.1 Molecular photoswitches 2
1.1.2 Towards visible and NIR photoswitching 3
1.1.3 Donor–acceptor Stenhouse adducts 3
1.2 Synthesis 5
1.3 Photoswitching 6
1.3.1 The absorption spectrum 7
1.3.2 Solid-state structures 11
1.3.3 Photoswitching 13
1.3.4 Cyclization under exclusion of light 15 1.3.5 Kinetics of cyclization and ring-opening 15
1.3.6 Solvent effects 19
1.4 Illustrative Applications 21
1.4.1 Drug delivery 21
1.4.2 Dynamic phase-transfer for catalyst recycling 23 1.4.3 Applications in polymers and on surfaces 23
1.4.4 Liquid crystals 29 1.4.5 Wavelength-selective photoswitching 30 1.4.6 Chemosensing 36 1.5 Stenhouse Photoswitches 43 1.6 Acknowledgments 44 1.7 References 45 Chapter 2
Orthogonal Photoswitching in a Multifunctional Molecular System 51
2.1 Introduction 52
2.2 Results and Discussion 53
2.2.1 Selection of a compatible photoswitch pair 53 2.2.2 Intermolecular combination of photoswitches 55 2.2.3 Structural scope of photoswitches 59 2.2.4 Orthogonal photoswitching in an intramolecular system 62 2.2.5 Model application in modulation of phase transfer and supramolecular
interactions 66
2.3 Conclusion 72
2.4 Acknowledgments 73
Preface I
2.5 Author Contributions 73
2.6 Experimental Data 74
2.6.1 Materials and Methods 74
2.6.2 Synthesis and Characterization 74
2.6.3 Binding Studies 83
2.6.4 Photochemical Characterization of Two-Photoswitch Mixtures 84
2.6.4.1 Mixture of compound 1 + 4 84
2.6.4.2 Mixture of compound 1 + 5 85
2.6.4.3 Mixture of compound 1 + 6 86
2.7 References 87
Chapter 3
Unravelling the Photoswitching Mechanism in Donor–Acceptor Stenhouse Adducts 93
3.1 Introduction 94
3.2 Results and Discussion 95
3.3 Conclusion 102
3.4 Acknowledgements 102
3.5 Author Contributions 103
3.6 Experimental Data 103
3.6.1 Materials and Methods 103
3.7 References 103
Chapter 4
Shedding Light on the Photoisomerization Pathway of Donor–Acceptor Stenhouse Adducts 109
4.1 Introduction 110
4.2 Results and Discussion 112
4.3 Conclusion 120
4.4 Acknowledgements 120
4.5 Author Contributions 121
4.6 Experimental Data 121
4.6.1 Materials and Methods 121
4.6.2 Synthesis and Characterization 123
4.6.3 Target analysis for DASA 1 125
4.7 References 127
Chapter 5
Tailoring Photoisomerization Pathways in Donor-Acceptor Stenhouse Adducts:
The Role of the Hydroxy Group 133
5.1 Introduction 134
5.2 Results and Discussion 137
xiii
I
5.2.2 Steady state spectroscopy 137
5.2.3 Time-resolved spectroscopy 143 5.2.4 1H-NMR in situ-irradiation experiments 148 5.3 Conclusions 153 5.4 Acknowledgments 153 5.5 Author Contributions 154 5.6 Experimental Data 154
5.6.1 Materials and methods 154
5.6.2 Synthesis and characterization 156
5.6.3 Photoswitching 159
5.7 References 162
Chapter 6
Solvent Effects in the Actinic Step of Donor–Acceptor Stenhouse Adducts Photoswitching 167
6.1 Introduction 168
6.2 Results and Discussion 171
6.3 Conclusion 177
6.4 Acknowledgments 177
6.5 Author Contributions 178
6.6 Experimental Data 178
6.6.1 Materials and Methods 178
6.6.2 Solvatochromic Shifts 180 6.6.3 Time-resolved spectroscopy 182 6.6.3.1 Compound 1 182 6.6.3.2 Compound 2 184 6.6.3.3 Compound 3 186 6.6.4 FTIR-spectroscopy 187 6.7 References 189 Chapter 7 Conclusion 195 Chapter 8 Research Prospect 203 8.1 Introduction 204 8.2 Photopharmacology 204
8.3 Wavelength-selective and orthogonal photocontrol 205
8.4 Functional responsive materials 208
8.5 Out-of-equilibrium systems 208
8.6 Conclusion 209
Summary 215 Samenvatting 217 Zusammenfassung 221 Popular Summary 227 Populär-Wissenschaftliche Zusammenfassung 229 Appendix – A
Materials and Methods 1
A.1 Synthesis 1
A.2 UV/visible static and steady state measurements 2 A.3 1H-NMR in situ-irradiation measurements 2
A.4 Light sources 2
A.4.1 Fiber-coupled LEDs 3
A.4.2 Optical Filters 3
A.5 References 3 Appendix – B Short Biography 4 Appendix – C List of Publications 5 Appendix – D Acknowledgements 7
xv
