Mechanistic investigation of catalytic organometallic reactions using ESI MS by Jingwei Luo M.Sc., Queen’s University, 2009 M.Sc., Minzu University of China, 2007 B.Sc., Minzu University of China, 2004 A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY in the Department of Chemistry © Jingwei Luo, 2014 University of Victoria All rights reserved. This dissertation may not be reproduced in whole or in part, by photocopy or other means, without the permission of the author. ii Supervisory Committee Mechanistic investigation of catalytic organometallic reactions using ESI MS by Jingwei Luo M.Sc., Queen’s University, 2009 M.Sc., Minzu University of China, 2007 B.Sc., Minzu University of China, 2004 Supervisory Committee Dr. J. Scott McIndoe, Department of Chemistry Supervisor Dr. Lisa Rosenberg, Department of Chemistry Departmental Member Dr. Frank van Veggel, Department of Chemistry Department Member Dr. Laurence Coogan, Department of Earth and Ocean Science Outside Member iii Abstract Supervisory Committee Dr. J. Scott McIndoe, Department of Chemistry Supervisor Dr. Lisa Rosenberg, Department of Chemistry Departmental Member Dr. Frank van Veggel, Department of Chemistry Department Member Dr. Laurence Coogan, Department of Earth and Ocean Science Outside Member Electrospray ionization mass spectrometry (ESI-MS) has been applied to the real time study of air-sensitive homogenous organometallic catalytic reactions due to its soft ionization properties. Therefore, fragile molecules and complexes in these reactions were characterized. The kinetic studies of these reactions have also been done by following the relative abundance of different species including starting material(s), products, by-product(s) as well as intermediates. Based on the results, reaction pathways and mechanisms were proposed and numerical models were built to accurately mimic the reactions under specific condition. In order to make the reactions detectable by ESI-MS, many charged ESI-MS friendly substrates were synthesized as tracking tags, including 1-allyl-1-(prop-2-yn-1-yl)piperidin-1-ium hexafluorophosphate(V), 1-allyl-1-(prop-2-yn-1-yl)pyrrolidin-1-ium hexafluorophosphate(V), (4-ethynylbenzyl)triphenylphosphonium hexafluorophosphate(V), hex-5-yn-1- yltriphenylphosphonium hexafluorophosphate(V) etc. The method for continuously monitoring water- and oxygen-sensitive reactions in real time named pressurized sample infusion (PSI) was developed, optimized and applied throughout all the projects in the thesis. These techniques were applied to detailed studies of the intramolecular Pauson-Khand reaction (PKR) with Co2CO8 under different temperatures. The kinetic study results gave the entropy and iv enthalpy of the reaction and evidence suggested that the ligand dissociation step was the rate- determining step of the reaction. Hydrogenation of alkynes with Wilkinson’s catalyst and Weller’s catalyst were also studied using PSI. The behaviour of starting materials and products were tracked, then various reactions were carried out by using different temperatures and concentrations. Furthermore, competition reaction and kinetic isotope effect study, mechanisms were proposed based on experimental results, numerical models were built, and rate constants for each step were estimated. Different Si-H activation reactions were studied including hydrolysis of silanes, hydrosilation, dehydrocoupling of silanes, alcoholysis of silane and silane redistribution by using (3- (methylsilyl)propyl)triphenylphosphonium hexafluorophosphate(V). A variety of collaborative projects were also carried out including hydroacylation, fast-activating Pd catalyst precursor, catalyst analysis for Cu-mediated fluorination, CdSe - NiDHLA analysis, Ru catalyzed propargylic amination reaction, Zn catalyzed lactide polymerization, and Fe4S4 clusters. v Table of Contents Supervisory Committee .................................................................................................................. ii Abstract .......................................................................................................................................... iii Table of Contents ............................................................................................................................ v List of Tables ................................................................................................................................ vii List of Schemes ............................................................................................................................ viii List of Figures ................................................................................................................................ ix List of Abbreviations ................................................................................................................... xvi List of Structures ........................................................................................................................ xviii Acknowledgments....................................................................................................................... xxii Dedication .................................................................................................................................. xxiii 1. Literature Review........................................................................................................................ 1 1.1 Organometallic catalysis ................................................................................................. 1 1.2 Traditional methods for analysis of organometallic reactions ........................................ 4 1.2.1 NMR Spectroscopy ..................................................................................................... 5 1.2.2 UV/Vis Spectroscopy................................................................................................ 11 1.2.3 IR Spectroscopy ........................................................................................................ 13 1.2.4 Mass Spectrometry.................................................................................................... 16 2. Techniques and methodologies ................................................................................................. 25 2.1 Introduction ................................................................................................................... 25 2.2 Electrospray Ionization Mass Spectrometry ................................................................. 26 2.3 Quadrupole –Time of Flight (Q-TOF) .......................................................................... 29 2.4 Continuous reaction monitoring with ESI-MS ............................................................. 33 3. Methodological innovations...................................................................................................... 37 3.1 Numerical modeling...................................................................................................... 37 3.2 Powersim model design ................................................................................................ 41 3.3 Handling air and moisture sensitive reactions .............................................................. 46 3.4 PSI-ESI-MS optimization ............................................................................................. 48 3.4.1 PSI-ESI-MS filter...................................................................................................... 48 3.4.2 PSI-ESI-MS dilution system ..................................................................................... 50 3.4.3 PSI glassware ............................................................................................................ 51 4. The Pauson-Khand Reaction ..................................................................................................... 54 4.1 Introduction ................................................................................................................... 54 4.2 Selected studies ............................................................................................................. 56 4.3 Challenges of ESI-MS for Pauson-Khand studies ........................................................ 57 4.4 Advantages of ESI-MS for the Pauson-Khand Reaction studies .................................. 58 4.5 Results and Discussion ................................................................................................. 59 4.5.1 Design of charged substrate ...................................................................................... 59 4.5.2 Synthesis of cobalt complexes .................................................................................. 60 4.5.3 Previous gas phase reaction ...................................................................................... 62 4.5.4 Intramolecular Pauson-Khand reaction ..................................................................... 63 4.6 Conclusion .................................................................................................................... 68 4.7 Experimental ................................................................................................................. 68 5. Detailed kinetic analysis of rhodium-catalyzed alkyne hydrogenation .................................... 75 5.1 Hydrogenation of olefins by Rh (PPh3)3Cl ..................................................................