Dual photo- and redox- active molecular switches for smart surfaces Ivashenko, Oleksii

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1 University of Groningen Dual photo- and redox- active molecular switches for smart surfaces Ivashenko, Oleksii 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: 2013 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Ivashenko, O. (2013). Dual photo- and redox- active molecular switches for smart surfaces Groningen: s.n. 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): For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date:

2 Dual photo- and redox- active molecular switches for smart surfaces Oleksii Ivashenko

3 This work was performed within Top Research School program of the Zernike Institute for Advanced Materials under the Bonus Incentive Scheme (BIS) of the Netherlands Ministry of Education, Science, and Culture and received additional support from the 'Stichting voor Fundamenteel Onderzoek der Materie (FOM)', which is financially supported by the 'Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)'. Cover: Switching of a smart surface activated by light and redox potential. Background colours represent photochemical switching of spiropyran between the ring-closed form (yellow) and the ring-opened form (violet-blue). Printed by: Ipskamp Drukkers B.V., Enschede, The Netherlands Zernike Institute for Advanced Materials PhD-thesis series ISSN: ISBN: (printed version) ISBN: (electronic version) ii

4 RIJKSUNIVERSITEIT GRONINGEN Dual photo- and redox- active molecular switches for smart surfaces Proefschrift ter verkrijging van het doctoraat in de Wiskunde en Natuurwetenschappen aan de Rijksuniversiteit Groningen op gezag van de Rector Magnificus, dr. E. Sterken, in het openbaar te verdedigen op vrijdag 24 mei 2013 om 16:15 uur door Oleksii Ivashenko geboren op 6 oktober 1986 te Poltavska obl., Oekraine iii

5 Promotores: Copromotor: Beoordelingscommissie: Prof. dr. P. Rudolf Prof. dr. B.L. Feringa Dr. W.R. Browne Prof. dr. R. Raval Prof. dr. R. Janssen Prof. dr. K. Müllen iv

6 T Introduction to electrochemistry of photochromic switches on surfaces Introduction to redox-active photochromic switches Electrochemical reduction of stilbenes 3 Photochemistry of stilbenes 3 Reduction with alkali metals 3 Cyclic voltammetry of stilbenes 3 Electrochemistry of stilbene based self-assembled monolayers Electrochemical reduction of azobenzenes in solution 6 Photochemistry of azobenzenes Electrochemical reduction of azobenzenes in monolayers Electrochemistry of rotaxanes Electrochemistry of dithienylethenes in solution Electrochemistry of dithienylethenes in monolayers 16 Monolayers on indium tin oxide Electrochemistry of spiropyrans in solution 19 Photochemistry of spiropyrans in solution and in monolayers 19 Reductive ring-opening of nitrospiropyrans 20 Oxidation of spiropyrans in solution 21 Oxidation of spiropyrans encapsulated in porous materials 23 Oxidation of spiropyrans in monolayers Electrochemistry of overcrowded alkenes in solution Outlook and outline of the thesis References 28 Experimental procedures 31 High energy conformers in SAMs of a bistable electro- and photoswitchable overcrowded alkene Introduction Results and discussion 41 Photochromism and redox switching in solution and solid state 41 Surface functionalization by self-assembly of switchable molecules 42 Photochemistry of monolayers on gold and quartz 46 Cyclic voltammetry of monolayers on gold and ITO 47 UV/Vis absorption and Surface enhanced Raman spectroelectrochemistry 50 X-rays photoelectron spectroscopy and contact angles of oxidized SAMs 51 v

7 Table of contents 3.3 Conclusions Synthesis and characterization of dication 2 2+ (PF6 - ) Experimental details Acknowledgments References 55 Rapid reduction of nitroaromatic SAMs on roughened Au surfaces during XPS measurements Introduction Results and discussion 60 Solid state Raman spectrum 60 SERS of self assembled monolayers on roughened gold bead electrodes 60 XPS spectra of a film and SAMs on roughened Au beads 60 XPS spectra of a SAM on flat and roughened Au surfaces 62 Intensities of Au 4f photoemission peak of SAMs on various substrates 63 SERS of a SAM on a roughened Au surface after exposure to X-rays Conclusions Acknowledgements References 67 UV/Vis and NIR Light-Responsive Spiropyran Self-Assembled Monolayers Introduction Results and discussion 72 ATR FTIR and Raman spectra of the spiropyran form 72 Photochemical switching between SP and MC forms in the solid state 72 X-ray photoelectron spectra of self-assembled monolayers on gold 74 Photochromic response of SAMs on semitransparent gold slides 76 Photochromic response of SAMs on roughened Au beads 76 Power and exposure time dependence of the spectra of SAMs on gold 77 Conversion of the SP to the MC form in films upon exposure to NIR light 79 Photochromism of SAM measured with minimum exposure to the NIR beam Conclusions References 83 Oxidative electrochemical aryl C-C coupling of spiropyrans Introduction Results and discussion 87 Cyclic voltammogram in solution 87 vi

8 Table of contents Characterization of spiropyran dimer 88 Photochromism of dimer in solution 90 Mechanism of electrochemical dimerization of DMA 91 Preventing dimerization 91 UV/Vis absorption spectroelectrochemistry of SP-Me Conclusions Experimental procedures 94 Bulk electrolysis of spiropyran monomer References 95 Electrochemical functionality of spiropyran SAMs on gold Introduction Results 101 Cyclic voltammograms of spiropyran SAMs on Au 101 SERS spectroelectrochemistry of SAMs on roughened Au bead electrodes 102 UV/Vis absorption spectroelectrochemistry of a SAM on semitransparent Au/glass 104 X-ray photoelectron spectra of SAM on Au/mica 105 Photochromism of dimers in SAMs 107 Electrochemistry of the MC form in a SAM on Au 109 Electrochemistry of MC dimers SAMs on Au Summary and outlook for utilization of the full spiropyran functionality in SAMs on Au Conclusions Experimental details Acknowledgements References 114 Summary 117 Samenvatting 120 CV 124 List of publications 125 Acknowledgements 126 vii

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10 Dedicated to my grandparents

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