QUEENSLAND UNIVERSITY OF TECHNOLOGY FACULTY OF SCIENCE SCHOOL OF CHEMISTRY AND PHYSICS SUBMITTED IN FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy Chemiluminescent Self-Reporting Macromolecular Transformation Fabian R. Bloesser MSc Chemistry 2021 “We scholars like to think science has all the answers, but in the end it’s just a bunch of unprovable nonsense.” Sorcerio, in Matt Groening’s Disenchantment, S1E3 Statement of Original Authorship The work contained in this thesis has not been previously submitted to meet require- ments for an award at this or any other higher education institution. To the best of my knowledge and belief, the thesis contains no material previously published or written by another person except where due reference is made. 21 June 2021 QUT Verified Signature ...................................................................... (Fabian R. Bloesser) Abstract Self-reporting systems play a major role in the detection and localisation of damages and mechanical stress in materials, the formation and reversion of networks, the detection of drug release as well as the presence of toxins in cells. While a change in colour or fluorescence have been the detection mode of choice in the past, chemiluminescence (CL) systems have attracted increasing interest in the past years, as CL provides a high sensitivity, allows for real-time monitoring and quantification, and does usually not require sophisticated equipment. Therefore, the current study focuses on the development of self-reporting CL systems for the quantification of bond formation and as a tool for on-line kinetic analysis where conventional analyses fail at providing valuable information. The para-fluoro – thiol reaction (PFTR) has recently been reported as an efficient tool for the formation of precision networks.1 While the PFTR forms relatively stable C-S bonds, it also releases a fluoride ion for every bond formed, which can be detected via CL using silyl-protected phenolic dioxetanes.2 Chapter 3 presents a preliminary study of the PFTR investigating its self-propagating properties. A pentafluorobenzyl (PFB) linker was reacted with a set of three structurally different thiols in three solvents of different polarity. It was found that both acidity of the thiol as well as solvent polarity do not only play an important role in the kinetic and efficiency of the reaction, but also that - depending on the exact thiol-solvent combination - the reaction proceeds quantitatively within only a few moments when understoichiometric amounts of base were used. In fact, the fluoride being released during the PFTR is sufficiently basic to deprotonate another thiol, thus propagating the PFTR. The fluoride itself, however, thus formed HF and was removed from the reaction system. These findings pathed the way for an in-depth study of the quantification of network bonds during PFTR via CL in Chapter 4. With the results of the first chapter at hand, the second part of the PhD program addresses the quantification of PFTR events via CL. Therefore, in a first step, a suitable PFB-trilinker was reacted with three different thiols at various concentrations. The fluoride that was released during the PFTR proved capable of cleaving the silyl-ether of a CL probe, thus triggering the emission of light. The integrated emission of all three thiols correlated linearly with the concentration of thiol used, i.e. with the expected conversion, as well as with the conversion as determined by 1H nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography (LC). Moreover, the emission was coherent with the emission of pure TBAF solutions at identical concentrations. Next, a 2000 g·mol-1 polyethylene glycol thiol (PEG-SH) was employed for formation of a three-arm star-polymer. Again, the total CL emission was recorded and, this time, the conversion vi was back-calculated based on the emission. Here too, the fluoride concentration as determined from CL was in good agreement with the conversion according to 1H NMR and LC. In a last step, PFTR of two bis-thiols was employed for the formation of two distinct networks. The supernatant solutions after network formation were subsequently analysed via CL read-out to obtain the absolute number of PFTR events and therefore network junctions. Critically, the presented method exhibits high sensitivity of down to 5·10-9 mol of fluoride and circumvents the necessity of degrading the networks. The last project of the present thesis employs the CL of phenyl oxalates (POs) to track the unfolding of single-chain nanoparticles (SCNPs). A set of linear polymer chains bearing photo-active ortho-methylbenzaldehyde (o-MBA) moieties as well as fluorophore moieties was synthesised. The o-MBA units were subsequently crosslinked intramolec- ularly using a previously reported bis-maleimide-PO linker3 and characterised via 1H NMR, diffusion-ordered NMR spectroscopy (DOSY) and size exclusion chromatogra- phy (SEC) to prove successful folding into SCNPs. Addition of hydrogen peroxide (H2O2) allowed for the targeted degradation of the PO-linker and the subsequent emission of light, which was recorded as a function of time. The SCNPs were then analysed via the methods mention above to confirm complete unfolding. The time-dependant emission data was subsequently employed for a parameter estimation using the PREDICI® soft- ware package. Hence, the presented method allows for on-line analysis of the SCNP unfolding and provides a qualitative assessment of the mechanism of SCNP unfolding. In conclusion, the present doctoral thesis established advanced optical read-out and characterisation methods for the in-depth analysis of chemical reaction system, such as quantification of reaction events or kinetic analysis, via state-of-the-art chemilumi- nescence systems. vii Contents Contents Abstract . vi Contents . viii Publications Included in the Present PhD Research Program . .x Additional Publications During the Candidature . .x Acknowledgements . xii List of Abbreviations . xiii 1 Motivation1 2 Introduction2 2.1 Networks . .4 2.1.1 Network Characterisation . .7 2.1.2 para-Fluoro – Thiol Reaction . 10 2.2 Single-Chain Nanoparticles . 14 2.2.1 Photo-Induced Chemistry as an Efficient Ligation Method . 16 2.2.2 Analysis of Single-Chain Nanoparticles . 20 2.3 Self-Reporting Systems . 24 2.4 Chemiluminescence . 26 2.4.1 1,2-Dioxetanes . 28 2.4.2 Peroxyoxalates . 32 2.4.3 Luminol . 39 3 Self-Propagated para-Fluoro – Thiol Reaction 40 3.1 Abstract . 40 3.2 Introduction . 41 3.3 Results and Discussion . 42 3.4 Conclusion . 49 4 Chemiluminescent Read-Out of para-Fluoro – Thiol Reaction Events 50 4.1 Abstract . 50 4.2 Introduction . 51 4.3 Results and Discussion . 52 4.4 Conclusion . 58 5 Chemiluminescent Unfolding of Single-Chain Nanoparticles 60 5.1 Abstract . 60 viii CONTENTS 5.2 Introduction . 61 5.3 Results and Discussion . 62 5.4 Conclusion . 68 6 General Discussion 69 6.1 Summary and Key Outcomes . 69 6.2 Conclusion and Future Perspective . 72 7 References 82 8 Appendix 104 8.1 Statements of Contribution . 106 8.2 Supporting Information for Chapter 3 . 110 8.3 Supporting Information for Chapter 4 . 121 8.4 Supporting Information for Chapter 5 . 145 List of Figures . 174 List of Schemes . 181 List of Tables . 184 ix Publications Included in the Present PhD Research Program Publications Included in the Present PhD Research Program Section 2.4.2: All Eyes on Visible Light Peroxyoxalate Chemiluminescence Read-Out Systems L. Delafresnaye, F. R. Bloesser, K. B. Kockler, C. W. Schmitt, I. M. Irshadeen, C. Barner-Kowollik, Chem. Eur. J. 2020,26, 114-127. Chapter 3: Self-Propagated para-Fluoro – Thiol Reaction F. R. Bloesser, F. Cavalli, C. Barner-Kowollik, L. Barner, Chem. Eur. J. 2019, 25, 10049-10053. Chapter 4: Chemiluminescent Read-Out of para-Fluoro – Thiol Reaction Events F. R. Bloesser, F. Cavalli, Sarah L. Walden, L. Barner, C. Barner-Kowollik, Chem. Commun. 2020, 56, 14996-14999. Chapter 5: Chemiluminescent Self-Reported Unfolding of Single-Chain Nanoparticles F. R. Bloesser, Sarah L. Walden, Ishrath M. Irshadeen, Lewis C. Chambers, C. Barner- Kowollik, 2020, Chem. Commun. 2021, 57, 5203-5206. The Statements of Contribution signed by all co-authors are attached to the Appendix. Additional Publications During the Candidature [1] Light-fueled dynamic covalent crosslinking of single polymer chains in non-equilibrium states Kodura, D.; Houck, H. A.; Bloesser, F. R.; Goldmann, A. S.; Du Prez, F. E.; Frisch, H.; Barner-Kowollik, C. Chem. Sci. 2021, Advance Article. [2] 2D Fabrication of Responsive Soft Matter Materials from a Single Photoresist Michalek, L.; Bialas, S.; Walden, S.; Bloesser, F.R.; Frisch, H.; Barner-Kowollik, C. Adv. Funct. Mater. 2020, 30, 2005328. x CONTENTS [3] Wavelength Selective Folding of Single Polymer Chains with Different Colors of Visible Light Frisch, H.; Kodura, D.; Bloesser, F. R.; Michalek, L.; Barner-Kowollik, C. Macromol. Rapid Commun. 2020, 41, 1900414. (Special Issue dedicated to 100 Years of Macromolecular Hypothesis, journal cover) [4] Mapping the Compaction of Discrete Polymer Chains by Size-Exclusion Chro- matography Coupled to High Resolution Mass Spectrometry Nitsche, T.; Steinkoenig, J.; De Bruycker, K.; Bloesser, F. R.; Blanksby, S. J.; Blinco, J. P.; Barner-Kowollik, C. Macromolecules 2019, 52, 2597-2606. [5] Controlling Chain Coupling and Single Chain Ligation by Two Colours of Visible Light Frisch, H.; Bloesser, F. R.; Barner-Kowollik, C. Angew. Chem. Int. Ed. 2019, 58, 3604-3609. [6] Fatty Acid-Derived Aliphatic Long Chain Polyethers by a Combination of Catalytic Ester Reduction and ADMET or Thiol-Ene Polymerization Dannecker, P-D.; Biermann, U.; Sink, A.; Bloesser, F.R.; Metzger, J.O.; Meier, M.A.R. Macromol. Chem. Phys. 2018, 1800440. [7] A Combined Photochemical and Multi-Component Reaction Approach to Precision Oligomers Konrad, W.; Bloesser, F. R.; Wetzel, K. S.; Boukis, A. C.; Meier, M. A. R.; Barner- Kowollik, C. Chem. Eur. J. 2018, 24, 3413-3419. [8] Photochemistry in Confined Environments for Single Chain Nanoparticle Design Frisch, H:, Menzel, J.