The Preparation and Characterization of Tungsten and Molybdenum Sulfide Fluorides

THE PREPARATION AND CHARACTERIZATION OF TUNGSTEN AND MOLYBDENUM SULFIDE FLUORIDES JARED NIEBOER B.Sc., University of Lethbridge, 2005 A Thesis Submitted to the School of Graduate Studies of the University of Lethbridge in Partial Fulfillment of Requirements for the Degree MASTER OF SCIENCE Department of Chemistry and Biochemistry University of Lethbridge LETHBRIDGE, ALBERTA, CANADA © Jared Nieboer, 2007 ABSTRACT + + + + Silanethiolate salts of K(18-crown-6) , N(CH3)4 , Cs , K were synthesized and characterized by vibrational and NMR spectroscopy. The [N(CH3)4][SSi(CH3)3] salt was used to prepare the new [N(CH3)4][WSF5] salt directly from WF6. Alternatively, [N(CH3)4][WSF5] was prepared by the reaction of WSF4 with [N(CH3)4][F]. Pure WSF4 was prepared via a facile new route and was fully characterized by Raman, infrared, and 19F NMR spectroscopy, and an improved crystal structure. The Lewis-acid properties of WSF4 were studied in reactions with pyridine, yielding the new 19 WSF4·C5H5N adduct, which was studied by Raman and F NMR spectroscopy. A 2:1 - stoichiometry of WSF4 and [N(CH3)4][F] yielded W2S2F9 in solution. The novel - 19 W2SOF9 anion was characterized in solution by F NMR spectroscopy. Molybdenum sulfide tetrafluoride was synthesized and unambiguously characterized by Raman, infrared, and 19F NMR spectroscopy and single-crystal X-ray diffraction. - - The experimental characterization of WSF4, MoSF4, WSF5 , and SSi(CH3)3 was supplemented by density functional theory calculations. ii ACKNOWLEDGEMENTS I would like to thank Prof. Michael Gerken for giving me the chance to work on an interesting and exciting research project. His patience, guidance, experience, enthusiasm, support and confidence in me were invaluable throughout my years of study. I appreciate having had the opportunity to share in his excitement for understanding fundamental chemistry. I would like to thank the other members of my committee René T. Boeré and Steve Patitsas for their interest and investment of time into helping me further my research. I would like to thank Prof. René T. Boeré for his patience, advice and for his instruction in the areas of X-ray crystallography and for introducing me to the value of density functional theory calculations. I would like to thank Prof. Steve Patitsas for many years ago encouraging me to get involved in research, which opened up a world of interesting topics and my life immensely. I thank Anwar Abo-Amer and Kati Schmuck for their company and their assistance during the course of my research. I would also like to thank the members of the Boeré Lab, Tracy Roemmele, Twyla Gietz, Maria Ksiaczek, Xin Yu for always keeping life interesting and David Franz and Marc Slingerland for their friendship throughout the my research time. I am grateful to have received the Keith and Hope Ferguson Memorial scholarship, which helped me cover so many costs associated with the pursuit of a graduate degree. I would like to acknowledge the Alberta Ministry of Education and the Department of Chemistry and the University of Lethbridge for their financial support. Finally, I thank my wife and parents for their constant support that helped me achieve my goal. iii TABLE OF CONTENTS Introduction ....................................................................................................................... 1 1.1 Introduction ....................................................................................................... 1 1.2 Tungsten and Molybdenum Fluorides ............................................................ 1 1.3 Tungsten and Molybdenum Oxide Fluorides ................................................. 4 1.4 Tungsten and Molybdenum Sulfide Fluorides ............................................... 8 1.5 Goal of Present Research ............................................................................... 14 References ........................................................................................................ 15 Chapter 2: Experimental Section .................................................................................. 18 2.1 Standard Techniques ...................................................................................... 18 2.2 Preparation and Purification of Starting Materials .................................... 23 2.2.1 Purification of HF, CH3CN, SO2ClF, THF Solvents and ((CH3)3Si)2S ........ 23 2.2.2 Purification of MoF6, WF6, SbF3 and SbF5................................................... 23 2.2.3 Drying of [N(CH3)4][F], CsF, KF, Sb2S3, Sb2S5 ........................................... 25 2.3 Synthesis of Silanethiolate Salts ..................................................................... 25 2.3.1 Preparation of [N(CH3)4][SSi(CH3)3] ........................................................... 25 2.3.2 Preparation of [K(18-crown-6)][SSi(CH3)3] ................................................. 26 2.3.3 Preparation of Cs[SSi(CH3)3] ....................................................................... 26 2.3.4 Preparation of K[SSi(CH3)3] ......................................................................... 27 2.4 Synthesis and Reactions of WSF4 .................................................................. 29 2.4.1 Synthesis of WSF4 in HF .............................................................................. 29 2.4.2 Reaction of WF6 with H2S in CFCl3 ............................................................. 29 2.5 Lewis-Acid Chemistry of WSF4 ..................................................................... 30 2.5.1 Reaction of WSF4 with Pyridine ................................................................... 30 2.5.2 Production of [N(CH3)4][WSF5] ................................................................... 30 2.5.3 Production of [N(CH3)4][WSF5] from WSF4 ................................................ 31 iv 2.6 Preparation of MoSF4 ..................................................................................... 31 2.6.1 Synthesis of MoSF4....................................................................................... 31 2.6.2 Attempted Preparation of MoSF4 from MoF6 with ((CH3)3Si)2S in CH3CN 32 2.6.3 Attempted Preparation of MoSF4 from MoF6 and H2S in CFCl3 ................. 32 2.6.4 Synthesis of MoF5 ......................................................................................... 33 2.6.5 Reaction of MoF5 with [N(CH3)4][SSi(CH3)3] ............................................. 33 - 2.7 Attempted Preparation of MoSF5 ................................................................. 33 2.7.1 Reaction of MoF6 with [N(CH3)4][SSi(CH3)3] in CH3CN ........................... 33 2.6.2 Reaction of MoSF4 with [N(CH3)4]F in CH3CN .......................................... 33 2.8 NMR Spectroscopy ......................................................................................... 34 2.9 Raman Spectroscopy ...................................................................................... 34 2.10 Infrared Spectroscopy .................................................................................... 34 2.11 Single Crystal X-ray Diffraction .................................................................... 35 2.11.1 Crystal Growth .............................................................................................. 35 2.11.2 Low-Temperature Crystal Mounting ............................................................ 35 2.11.3 Collection and Reduction of X-ray Data ...................................................... 36 2.11.4 Solution and Refinement of Structures ......................................................... 36 2.12 Computational Results ................................................................................... 38 References ........................................................................................................ 39 Chapter 3: Synthesis and Characterization of Silanethiolate Salts ........................... 40 3.1 Introduction ..................................................................................................... 40 3.2 Results and Discussion .................................................................................... 41 3.2.1 Preparation of Trimethylsilanethiolate Salts ................................................. 41 3.2.2 Vibrational Spectroscopy of Trimethylsilanethiolate Salts .......................... 42 3.2.3 Density Functional Theory Calculations of Silanethiolate Salts .................. 53 3.2.4 NMR Spectroscopy of Silanethiolate Salts ................................................... 56 3.2 Summary .......................................................................................................... 58 References ....................................................................................................... 59 v Chapter 4: Synthesis and Characterization of WSF4 .................................................. 60 4.1 Introduction ..................................................................................................... 60 4.2 Results and Discussion .................................................................................... 60 4.2.1 Synthesis of WSF4 ........................................................................................ 60 4.2.2 X-ray Crystal Structure of WSF4 .................................................................. 63 4.2.3 NMR Spectroscopy of WSF4 ........................................................................ 68 4.2.4 Vibrational Spectroscopy of WSF4 ..............................................................

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