Doctoral Dissertation Template
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UNIVERSITY OF OKLAHOMA GRADUATE COLLEGE IMITATING NATURE: THE EFFECTS OF ASYMMETRY AND STRAIN ON COPPER AND IRON COMPLEXES WITH SCHIFF BASE LIGANDS A DISSERTATION SUBMITTED TO THE GRADUATE FACULTY in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY By ANNA MARIA JOZWIUK Norman, Oklahoma 2013 IMITATING NATURE: THE EFFECTS OF ASYMMETRY AND STRAIN ON COPPER AND IRON COMPLEXES WITH SCHIFF BASE LIGANDS A DISSERTATION APPROVED FOR THE DEPARTMENT OF CHEMISTRY AND BIOCHEMISTRY BY ______________________________ Dr. Daniel T. Glatzhofer, Chair ______________________________ Dr. Robert P. Houser ______________________________ Dr. Robert K. Thomson ______________________________ Dr. Kenneth M. Nicholas ______________________________ Dr. Ronald L. Halterman ______________________________ Dr. Lee R. Krumholz © Copyright by ANNA JOZWIUK 2013 All Rights Reserved. For my grandparents Maria and Jerzy Acknowledgements First and foremost I want to thank my main advisor, Dr. Robert Houser, for the great freedom in my projects and your faith in my independent work. At the same time you gave enough guidance and suggestions to accomplish the research projects. You managed to always make time for my cultural misunderstandings and any research related difficulties no matter how busy you were. Secondly, but certainly not less, I am thanking my current advisor, Dr. Daniel Glatzhofer, for adopting me into your group after Dr. Houser’s departure and allowing me to complete my dissertation with a reasonably sized and fitting project. You showed me how to look at problems from the organic perspective. Thanks to my committee members Dr. Nicholas, Dr. Thomson, Dr. Halterman and Dr. Krumholz, and also to the ones previously served on my committee, Dr. Cichewicz and Dr. Nanny. I would like to acknowledge the Richter-Addo and the Nicholas group for letting me use some of their instrumentation. I value the work of Dr. Powell, who did all the crystallography presented in this dissertation and Dr. Foster who performed the mass spectrometry measurements. Very much appreciated are GC-MS measurements conducted by Dr. Smith for Chapter 4. Dr. Warhausen’s help with the spectro-electro chemical measurements is also greatly appreciated. Thanks to my former group members Zhaodong, Audrey, especially Mike and Adam for your great friendship and support in the group. Sachin, thank you for allowing me to have a smooth start in the new group and for an encouraging atmosphere in the final steps of our dissertations! I also want to thank my current group members for accepting me into the group and for a warm transition. iv Further I want to thank the staff at the Chemistry Department, in particular our glass blower Jim and Chad & Carl from the electronic shop. Without their support, part of my projects could not have been realized. I am thankful for my roommates, Mike and Whitney, for giving me a second home and being my family in the US. I am extremely grateful for the dedication and support from my parents, without whom it would have not been possible to accomplish this goal of graduating with a Ph. D. I also want to thank my grandparents who always believed in me. Thanks to my brother, Peter, for his spiritual support during my entire chemistry career. Last but not least, thanks to the department of aviation for allowing me to enroll in flight classes and providing some respite from chemistry, especially during difficult times and transition to the new group. Chip, you were a great flight instructor and I am very thankful for your hard work with me and faith to accomplish my goal to earn my license. v Table of Contents Acknowledgements ......................................................................................................... iv Table of Contents ............................................................................................................ vi List of Tables .................................................................................................................... x List of Figures .................................................................................................................. xi List of Schemes ............................................................................................................. xix Abbreviations ................................................................................................................. xx Abstract ........................................................................................................................ xxiv CHAPTER 1 Introduction ................................................................................................ 1 1.1 Bioinorganic Chemistry ........................................................................................ 2 1.2 Bioinorganic Modeling ......................................................................................... 8 1.3 Previous Studies ................................................................................................. 14 1.4 Project Goals ...................................................................................................... 19 1.4 References .......................................................................................................... 21 CHAPTER 2 Unsupported, Asymmetric (Hydr)oxo-bridged Diiron Complexes .......... 27 2.1 Background ......................................................................................................... 28 2.1.1 Proteins with Diiron Cores ........................................................................ 28 2.1.2 Model Complexes for Diiron Sites ............................................................ 38 2.2 Introduction ........................................................................................................ 48 2.3 Syntheses ............................................................................................................ 52 2.4 Solid State Structures ......................................................................................... 55 vi 2.4.1 X-ray Crystal Structures ............................................................................ 55 2.4.2 Hydrogen Bonding Pocket ........................................................................ 65 2.5 Chemical Reduction of [(FeL)2(µ-OH)]BPh4 ..................................................... 69 2.6 Electrochemistry ................................................................................................. 75 2.7 Spectroscopic Properties of Complexes ............................................................. 80 2.8 Characterization of [(FeL)2] and Its Lability Towards Dioxygen ...................... 82 2.9 Conclusion .......................................................................................................... 84 2.10 Experimental ..................................................................................................... 85 2.10.1 General .................................................................................................... 85 2.10.2 Synthesis of [(FeL)2(µ-OH)]BPh4 via Alternate Route ........................... 86 2.10.3 Titration of [(FeL)2(µ-OH)]BPh4 with Cobaltocene ............................... 87 2.10.4 Synthesis of [(FeL)2(µ-O)]: Reaction of [(FeL)2(µ-OH)]BPh4 with Cobaltocene ............................................................................................ 87 2.10.5 Synthesis of [(FeL)2] ............................................................................... 88 2.10.6 Reactivity of the Diferrous Complex ...................................................... 89 NO2 2.10.7 [(FeL )2(µ-OH)]ClO4 ........................................................................... 89 2.10.8 X-ray Crystal Structure Determination ................................................... 90 2.11 References ........................................................................................................ 93 CHAPTER 3 Copper(II) Complexes of Symmetric and Asymmetric Bis(imine) Ligands: Tuning the Cu(I)/Cu(II) Redox Couple ............................................. 103 3.1 Background ....................................................................................................... 104 3.2 Introduction ...................................................................................................... 114 vii 3.3 Ligands ............................................................................................................. 117 3.3.1 Syntheses of Ligands ............................................................................... 117 3.3.2 Confomers of the Hexahydropyrimidine Molecule ................................. 124 3.4 Synthesis of the Copper Complexes ................................................................. 128 3.5 X-ray Crystal Structures ................................................................................... 131 3.6 Spectroscopic Characterization ........................................................................ 138 3.7 Electrochemical Studies ................................................................................... 140 3.8 Conclusion ........................................................................................................ 144 3.9 Experimental ..................................................................................................... 146 3.9.1 General Procedures .................................................................................. 146 3.9.2 Synthesis of HL2