HYDROGEN BOND DIRECTED SELF-ASSEMBLY OF ARENES By DANIELLE ELIZABETH FAGNANI A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2018 © 2018 Danielle Elizabeth Fagnani To the forthcoming peruser ACKNOWLEDGMENTS I first thank my family for their endless cheer and support. My dad, mom, and brother each have been essential in this journey away from home. I am grateful that we can share in all these moments. My sincerest gratitude goes to my advisor, Prof. Ron Castellano. I thank him for sharing his expertise in conducting scientific research, providing a profound and joyful understanding of chemistry, and offering guidance beyond the molecules. The encouragement he provided throughout the entirety of my doctoral studies is truly appreciated beyond words. I thank all my labmates for being an excellent group of people to spend my time with in Sisler Hall and for teaching me something new every day. I thank Drs. Raghida Bou Zerdan and Davita Watkins for their everlasting mentorship and for inspiring me to be a better chemist. I thank Renan for sharing his synthetic prowess, Ashton for her optimism, Asme and Lei for being magnificent teammates, and Ania (and Cher) for always lending a helping hand and never letting a dull moment pass. I thank Dylan for providing me with a wonderful mentoring experience, and Will and Elham for their cheerful energy. I thank all my collaborators, especially Dr. Jiangeng Xue and his student Daken Starkenburg. I thank my committee members, Dr. Lisa McElwee-White, Dr. Dan Talham, Dr. Brent Sumerlin, and Dr. Anthony Brennan for their input and support over the years. Last but not least, I thank the friends I made in Gainesville for their mutual camaraderie and comedic relief. Graduate school would not have been nearly as enjoyable, nor minimally bearable, without them. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 9 LIST OF FIGURES ........................................................................................................ 10 LIST OF SCHEMES ...................................................................................................... 19 LIST OF ABBREVIATIONS ........................................................................................... 21 ABSTRACT ................................................................................................................... 24 CHAPTER 1 INTRODUCTION .................................................................................................... 26 Arenes .................................................................................................................... 26 Pi-Pi Interactions .............................................................................................. 26 Expanding the Pi-Surface .......................................................................... 30 Emergent Properties Upon Stacking ................................................................ 32 Optical Properties ...................................................................................... 32 Charge mobility .......................................................................................... 34 Redox Properties ....................................................................................... 35 Using Hydrogen Bonds to Guide Arene Assembly ................................................. 36 Examples from Nature ...................................................................................... 37 Synthetic Supramolecular Materials ................................................................. 39 In-Plane Hydrogen Bonding ....................................................................... 40 Out-of-plane Hydrogen Bonding ................................................................ 41 Motivation of Dissertation ........................................................................................ 42 2 STRUCTURE-PROPERTY INVESTIGATION OF NUCLEOBASE CONTAINING PI-CONJUGATED MATERIALS ............................................................................. 45 Introductory Remarks.............................................................................................. 45 Molecular Design .................................................................................................... 46 Synthesis ................................................................................................................ 47 Adenine and Guanine Oligomers ..................................................................... 47 Uracil Oligomer ................................................................................................. 48 Cytosine Oligomer ............................................................................................ 49 Optoelectronic Properties ....................................................................................... 50 Computations ................................................................................................... 50 Absorption ........................................................................................................ 51 Electrochemistry ............................................................................................... 53 Thermal Properties ................................................................................................. 54 5 Self-Association ...................................................................................................... 56 Hetero-Association ................................................................................................. 60 Adenine and Uracil Base-Pairing ...................................................................... 60 Guanine and Cytosine Base-Pairing ................................................................ 62 Concluding Remarks............................................................................................... 65 Experimental ........................................................................................................... 67 Synthesis .......................................................................................................... 67 Computations ................................................................................................... 69 UV-Vis Spectroscopy ....................................................................................... 70 Electrochemistry ............................................................................................... 70 Thermal Gravimetric Analysis ........................................................................... 71 Differential Scanning Calorimetry ..................................................................... 71 Binding Studies ................................................................................................ 71 3 GUANINE TERMINATED LOW ENERGY GAP PI-CONJUGATED OLIGOMERS .......................................................................................................... 73 Introductory Remarks.............................................................................................. 73 Molecular Design .................................................................................................... 77 Ditopic Design .................................................................................................. 77 Interior Chromophore Selection ........................................................................ 77 Target Molecules .............................................................................................. 78 Computations .......................................................................................................... 79 Synthesis ................................................................................................................ 80 Purification .............................................................................................................. 82 Metal-Free G-Quartet Formation ............................................................................ 85 Photophysical Properties ........................................................................................ 86 UV-Vis Absorption ............................................................................................ 86 Emission ........................................................................................................... 88 Thermal Properties ................................................................................................. 88 Concluding Remarks............................................................................................... 89 Experimental ........................................................................................................... 91 Synthesis .......................................................................................................... 91 UV-Visible Spectroscopy ................................................................................ 103 Fluorescence Spectroscopy ........................................................................... 104 4 METHYL SCAN OF GUANINE: TRANSLATING A BIO-INSPIRED MEDICINAL CHEMISTRY APPROACH TO OPTOELECTRONIC MATERIALS DISCOVERY 105 Introductory