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Metal Catalyzed Group 14 and 15 Bond Forming Reactions: Heterodehydrocoupling and Hydrophosphination Michael Cibuzar University of Vermont

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University of Vermont ScholarWorks @ UVM Graduate College Dissertations and Theses Dissertations and Theses 2019 Metal Catalyzed Group 14 And 15 Bond Forming Reactions: Heterodehydrocoupling And Hydrophosphination Michael Cibuzar University of Vermont Follow this and additional works at: https://scholarworks.uvm.edu/graddis Part of the Inorganic Chemistry Commons Recommended Citation Cibuzar, Michael, "Metal Catalyzed Group 14 And 15 Bond Forming Reactions: Heterodehydrocoupling And Hydrophosphination" (2019). Graduate College Dissertations and Theses. 1023. https://scholarworks.uvm.edu/graddis/1023 This Dissertation is brought to you for free and open access by the Dissertations and Theses at ScholarWorks @ UVM. It has been accepted for inclusion in Graduate College Dissertations and Theses by an authorized administrator of ScholarWorks @ UVM. For more information, please contact [email protected]. METAL CATALYZED GROUP 14 AND 15 BOND FORMING REACTIONS: HETERODEHYDROCOUPLING AND HYDROPHOSPHINATION A Dissertation Presented by Michael Patrick Cibuzar to The Faculty of the Graduate College of The University of Vermont In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Specializing in Chemistry May, 2019 Defense Date: March 21, 2019 Dissertation Examination Committee: Rory Waterman, Ph.D., Advisor John M. Hughes, Ph.D., Chairperson Matthew D. Liptak, Ph.D. Adam C. Whalley, Ph.D. Cynthia J. Forehand, Ph.D., Dean of the Graduate College ABSTRACT Investigation of catalytic main-group bond forming reactions is the basis of this dissertation. Coupling of group 14 and 15 elements by several different methods has been achieved. The influence of Si–N heterodehydrocoupling on the promotion of α-silylene elimination was realized. Efficient Si–N heterodehydrocoupling by a simple, earth abundant lanthanide catalyst was demonstrated. Significant advances in hydrophosphination by commercially available catalysts was achieved by photo- activation of a precious metal catalyst. 3– Exploration of (N3N)ZrNMe2 (N3N = N(CH2CH2NSiMe3)3 ) as a catalyst for the cross-dehydrocoupling or heterodehydrocoupling of silanes and amines suggested silylene reactivity. Further studies of the catalysis and stoichiometric modeling reactions hint at α-silylene elimination as the pivotal mechanistic step, which expands the 3p elements known to engage in this catalysis and provides a new strategy for the catalytic generation of low-valent fragments. In addition, silane dehydrocoupling by group 1 and 2 metal bis(trimethylsilyl)amide complexes was investigated. Catalytic silane redistribution was observed, which was previously unknown for d0 metal catalysts. La[N(SiMe3)2]3THF2 is an effective pre-catalyst for the heterodehydrocoupling of silanes and amines. Coupling of primary and secondary amines with aryl silanes was achieved with a loading of 0.8 mol % of La[N(SiMe3)2]3THF2. With primary amines, generation of tertiary and sometimes quaternary silamines was facile, often requiring only n a few hours to reach completion, including new silamines Ph3Si( PrNH) and i Ph3Si( PrNH). Secondary amines were also available for heterodehydrocoupling, though they generally required longer reaction times and, in some instances, higher reaction temperatures. By utilizing a diamine, dehydropolymerization was achieved. The resulting polymer was studied by MS and TGA. This work expands upon the utility of f-block complexes in heterodehydrocoupling catalysis. Stoichiometric and catalytic P–E bond forming reactions were explored with ruthenium complexes. Hydrophosphination of primary phosphines and activated alkenes was achieved with 0.1 mol % bis(cyclopentadienylruthenium dicarbonyl) dimer, [CpRu(CO)2]2. Photo-activation of [CpRu(CO)2]2 was achieved with a commercially available UV-A 9W lamp. Preliminary results indicate that secondary phosphines as well as internal alkynes may be viable substrates with this catalyst. Attempts to synthesize ruthenium phosphinidene complexes for stoichiometric P–E formation have been met with synthetic challenges. Ongoing efforts to synthesize a ruthenium phosphinidene are discussed. The work in this dissertation has expanded the utility of metal-catalyzed main- group bond forming reactions. A potential avenue for catalytic generation low-valent silicon fragments has been discovered. Rapid Si–N heterodehydrocoupling by an easily obtained catalyst has been demonstrated. Hydrophosphination with primary phosphines has been achieved with a commercially available photocatalyst catalyst, requiring only low intensity UV light. CITATIONS Material from this dissertation has been published in the following form: Cibuzar, M. P., Waterman, R.. (2018). Si–N Heterodehydrocoupling with a Lanthanide Compound. Organometallics, 23, 4395-4401. Erickson, K. A., Cibuzar, M. P., Waterman, R.. (2018). Catalytic N–Si coupling as a vehicle for silane dehydrocoupling via alpha-silylene elimination. Dalton Trans. 47, 2138-2142. ii ACKNOWLEDGEMENTS I would like to thank the NSF for funding throughout my graduate studies. I would like to thank two people at the University of Minnesota who were instrumental in starting this journey. First, I would like to thank Dr. Aaron Massari for his willingness to take a chance on me. Second, a big shout out to Dr. Ian Tonks. His passion for organometallic chemistry is infectious and inspiring. I couldn’t have asked for a better chemistry role model. I had the pleasure of working with some wonderful people in the Waterman group. A big thanks to Justin for being a great role model. After getting back from some meetings with Rory and not having a clue what he was talking about, without Justin’s help digesting the chemistry and deciphering Rory’s chicken scratches, I’d still be lost. No one has made me feel like this group is a family like Brandon. Thank you for always being my drinking buddy and my number two. Lastly, I had the pleasure of spending nine months with James. That time was my happiest in all my time at UVM. One cannot ask for a better friend. To my coworkers that don’t see their names here, I love you and thank you for being a part of my journey. A big shout out to Michelle, Teruki, Scott, Cam, Trevor and all my volleyball friends. Thank you for taking my mind off tough days at work, making me laugh and kicking butt on the court. You guys were so often the highlight of my week. iii Thanks to Manhattan’s Pizza Pub for sustaining me most Friday afternoons. I will greatly miss Matt and Philly Friday. I’d like to thank Hemi Sawant for always putting life in perspective for me. I couldn’t ask for a more generous friend. I have had the pleasure of having two great scientists in Matt ‘Matty Ice’ Liptak and (Adam) Whalley on my committee. I looked forward to asking for help from you guys. Thank you for all the help you’ve given and your contributions to my success. I cannot thank Rory enough for not only helping me to become a better scientist, but also making me a better person. You were the reason I came to UVM, and I’ve never regretted that decision. Thank you for everything that you’ve done. Dad, you are my inspiration. If I amount to half the man you are, I’ll be doing amazing. Mom, thank you for always reminding me to love. I hope to make you both proud. Erin, I would like to thank you everything you’ve done for me. I’m not sure how I would have lived the past few years without you. Besides the insufferable gremlin cat you brought into our home, you’ve made my life better in every way. I love you, and I can’t wait to start the next chapter of my life with you. iv TABLE OF CONTENTS CITATIONS ....................................................................................................................... ii ACKNOWLEDGEMENTS ............................................................................................... iii LIST OF FIGURES ......................................................................................................... viii LIST OF TABLES ............................................................................................................ xii CHAPTER 1: INTRODUCTION ....................................................................................... 1 1.1. Goals of this thesis ................................................................................................. 1 1.2. Si–N Coupling ....................................................................................................... 2 1.3. P–C coupling by hydrophosphination ................................................................. 11 1.4. References............................................................................................................ 13 CHAPTER 2: EXPLORING α-SILYLENE ELIMINATION WITH ZIRCONIUM AND ALKALI-BASED CATALYSTS ........................................................................... 22 2.1. Introduction.......................................................................................................... 22 2.2. Si–N heterodehydrocoupling and α-silylene elimination .................................... 31 2.3. Dehydrocoupling by group 1 and 2 metal compounds ........................................ 45 2.4. Enhancing reactivity using N-heterocyclic carbenes ........................................... 50 2.5. Future direction .................................................................................................... 52 2.6. Conclusion ........................................................................................................... 53
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  • Ethane / Nitrous Oxide Mixtures As a Green Propellant to Substitute Hydrazine: Validation of Reaction Mechanism C

    Ethane / Nitrous Oxide Mixtures As a Green Propellant to Substitute Hydrazine: Validation of Reaction Mechanism C

    Ethane / Nitrous Oxide Mixtures as a Green Propellant to Substitute Hydrazine: Validation of Reaction Mechanism C. Naumann*, C. Janzer, U. Riedel German Aerospace Center (DLR), Institute of Combustion Technology Pfaffenwaldring 38-40, 70569 Stuttgart, Germany Abstract The combustion properties of propellants like ethane / nitrous oxide mixtures that have the potential to substitute hydrazine or hydrazine / dinitrogen tetroxide in chemical propulsion systems are investigated. In support of CFD- simulations of new rocket engines powered by green propellants ignition delay times of ethane / nitrous oxide mixtures diluted with nitrogen have been measured behind reflected shock waves at atmospheric and elevated pressures, at stoichiometric and fuel-rich conditions aimed for the validation of reaction mechanism. In addition, ignition delay time measurements of ethene / nitrous oxide mixtures and ethane / O2 / N2 - mixtures with an O2:N2 ratio of 1:2 as oxidant at the same level of dilution are shown for comparison. Finally, the ignition delay time predictions of a recently published reaction mechanism by Glarborg et al. are compared with the experimental results. Introduction waves at initial pressures of pnominal = 1, 4, and 16 bar. Hydrazine and hydrazine derivatives like The results are compared to ignition delay time monomethyl hydrazine (MMH) and unsymmetrical measurements of stoichiometric C2H4 / N2O mixtures dimethyl hydrazine (UDMH) are used for spacecraft (see [6], [7], [8]). Complementary, ignition delay times propulsion applications in various technological of the corresponding oxygen based reactive mixture contexts despite their drawback of being highly toxic. C2H6 / (1/3 O2 + 2/3 N2) have been measured, too. Today, hydrazine consumption for European space Thereafter, the predictions of a recently published activities is on the order of 2-5 tons per year.