SYNTHESIS AND FUNCTIONALIZATION OF 1,4-POLYKETONES AND ENANTIOSELECTIVE POLYESTER CATALYST DEVELOPMENT USING MOLECULAR LEGO SCAFFOLDS A Dissertation Submitted to the Temple University Graduate Board In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY by Evan M. Samples May 2019 Examining Committee Members: Graham E. Dobereiner, Ph.D, Dissertation Supervisor, Temple University Ann M. Valentine, Ph.D., Temple University Stephanie L. Wunder, Ph.D., Temple University Deanna L. Zubris, Ph.D., External Member, Villanova University © Copyright 2019 by Evan M. Samples All Rights Reserved ii ABSTRACT Objectives of the present study are aimed towards improving upon alternating copolymerization techniques for polyketones and aliphatic polyesters, and the majority of this work focused on post-polymerization modifications to alternating polyketones. These materials are currently understudied in the literature, but the aptly spaced, repeating carbonyl functionality creates an easily functionalized material. Complementary work described herein relates to efforts currently underway to prepare highly enantioselective catalysts for the alternating copolymerization of epoxides with cyclic anhydrides. Aliphatic polyesters currently suffer from a lack of chemical diversity, and, with greener chemistries on the forefront of research efforts, polyesters made from environmentally benign and/or renewable materials are desirable. Additional limitations of aliphatic polyesters include difficulty obtaining stereoregular polyesters. In collaboration with the Schafmeister laboratory we are developing catalysts for the alternating copolymerization of polyesters to address these limitations. The model catalysts are carefully designed scaffolds of spiroligomers encasing a Lewis acidic transition metal at its center ([spiro]MX). The spiroligomer bulk around the metal center imparts significant chirality onto the catalyst thereby controlling which enantiomer of a given monomer is polymerized leading to stereoregular polyesters. Additionally, the use of more than one monomer increases the available chemical space with which to create novel polyesters. To date, three [spiro]MX catalysts have been prepared all of which are catalytically active for poly(propylene maleate) synthesis. iii A core objective of this work is the study of functionalization methods to create novel materials from inexpensive polyketones. The chemical modifications performed on polyketones to date have been limited, and the utility of the functionalized materials often goes unmentioned. Efforts to functionalize polyketones in this study were aimed at creating electrically conducting polymeric materials which would be used as hole transport materials in photovoltaic devices. Polyketones were decorated with pendant (tri)arylamine functionality creating several novel polymeric materials, and electrochemical experiments supported the formation of radical cations at the triarylamine nitrogen of the pendants. Further, the functionalization of the polyketones provided enhanced ultraviolet stability of the functionalized polymers. Concurrent to the functionalization of polyketones, we investigated the effects Lewis acids had on the synthesis of the polyketone itself. Through previous research conducted in the Dobereiner laboratory we know that a Lewis acid will interact with carbonyls of molecules during catalytic reactions. The addition of Lewis acids to the synthesis of the polyketones is thought to have similar interactions altering the polymerization. This study explored the bulk properties of the polyketone synthesized in the presence of several Lewis acids. As a result of this study specific polymer properties (e.g. molecular weight) could be targeted through careful selection of the Lewis acid and the amount added during polymerization. iv DEDICATION This dissertation is dedicated to my parents Ron and Judy Samples and to my sisters Emily and Sarah for their unwavering love and support. v ACKNOWLEDGMENTS After graduating from college, I never expected to go to graduate school for a PhD, and I definitely did not expect to find myself in an organometallic laboratory. Working with Dr. Graham Dobereiner has been a great experience from start to finish. Graham has taught me so much about chemistry, and I am grateful to have him as a mentor and a friend. It has been a great experience building up a research lab over the years and watching the group grow from just Derek and I to a full-fledged research group. Thanks to Dr. Ann Valentine for serving on my committee and providing scholarly advice during my time at Temple. Thank you to Dr. Stephanie Wunder for serving as a member on my advisory committee, and for being an invaluable resource for polymer chemistry. I would like to thank Dr. Deanna Zubris for serving as an external committee member, and for offering valuable research insight during my first years of graduate studies. Dr. Bradford Wayland has been an enthusiastic teacher and mentor during my inorganic chemistry studies and I have learned much from him. I would also like to thank Dr. Charles Debrosse for his spectroscopic expertise and maintenance of the NMR facilities. Dr. Debrosse was always willing to help with NMR experiments and spectral analyses. My colleagues and labmates (past and present) in the Dobereiner lab have provided a great work environment. Dr. Kushan Weerasiri and Alan Shaffer were great labmates who were always helpful when I needed a different view of my chemistry. Additional gratitude is due to Alexa Wallace and Jeremy Schuck for being such hard working undergraduates that I have had the pleasure of mentoring through the years. The vi chemistry department at Temple University is very collaborative, and so I must thank Dr. Kallie Willets, Dr. Padmanabh Joshi, and Dr. Drew Wilson of the Willets laboratory for their electrochemical expertise which played a significant role during my research. I have made many friends at Temple who have made the years fly by. Specifically, I want to acknowledge Derek Wozniak, Lauren Martin, Dr. Brenden Derstine, Dr. Christiana Teijaro, Dr. Colleen Keohane, Dr. Andrew Steele, and Alex Koval for all the happy hours, Wednesday wings, journal club shenanigans, and road trips we have had together. Not only are these people great friends, but they are incredibly helpful and supportive. Mostly, I need to acknowledge and thank my amazing family. My mother and father have been hugely supportive during my college career and further in my graduate studies. They have always pushed me to be my best and have always been enthusiastic about my research even when they do not understand it. In addition, my sisters are incredibly smart and funny. They always have rock solid advice for me in any situation, and I know that I can count on them for anything. vii TABLE OF CONTENTS Page ABSTRACT ..................................................................................................................... III DEDICATION................................................................................................................... V ACKNOWLEDGMENTS .............................................................................................. VI LIST OF TABLES ............................................................................................................ X LIST OF FIGURES ........................................................................................................ XI CHAPTER 1 INTRODUCTION ......................................................................................1 1.1 Statement of Dissertation Objectives .................................................................1 1.2 Background to Polyketones ...............................................................................2 1.3 Mechanism of Polyketone Formation with Cationic Palladium Species ...........4 1.4 Post-polymerization Functionalization of Polyketones .....................................7 1.5 Alternating Copolymers and Stereo-control ....................................................11 1.6 Background to Aliphatic Polyesters.................................................................14 1.7 Summary ..........................................................................................................17 1.8 References Cited ..............................................................................................19 CHAPTER 2 POLYKETONE FUNCTIONALIZATION FOR HOLE TRANSPORT ...................................................................................................................25 2.1 Introduction ......................................................................................................25 2.2 Results and Discussion ....................................................................................29 2.2.1 Polyketone Synthesis ...........................................................................29 2.2.2 Functionalization of Polyketone ..........................................................31 2.2.2.1 Reductive Amination .......................................31 2.2.2.2 Paal-Knorr Cyclization of 1,4-polyketone .......34 2.2.3 Properties of Functionalized Polyketones ............................................41 2.2.3.1 Azobenzene-derived Polyketone .....................41 2.2.3.2 Triarylamine-functionalized Polyketones ........46 2.2.3.3 Substituted Pyrrole Model Compounds ...........58 2.3 Conclusion .......................................................................................................65