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Matrix Isolation and Quantum-Chemical Study of Molecules Containing Transition Metals in High Oxidation States

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Matrix Isolation and Quantum-Chemical Study of Molecules Containing Transition Metals in High Oxidation States Matrix Isolation and Quantum-chemical Study of Molecules containing Transition Metals in High Oxidation States Inauguraldissertation zur Erlangung des akademischen Grades eines Doctor rerum naturalium (Dr. rer. nat.) der Fakult¨at fur¨ Chemie und Pharmazie der Albert-Ludwigs-Universit¨at Freiburg i. Br. vorgelegt von Tobias Schl¨oder aus Bonn 2013 Dekan: Prof. Dr. Bernhard Breit Vorsitzender des Promotionsausschusses: Prof. Dr. Thorsten Koslowski Betreuer der Arbeit: Dr. Sebastian Riedel Referent: Dr. Sebastian Riedel Korreferent: Prof. Dr. Ingo Krossing Datum der mundlichen¨ Prufung:¨ 30. April 2013 Die vorliegende Arbeit wurde im Zeitraum von Januar 2010 bis April 2013 am Institut fur¨ Anorganische Chemie der Albert-Ludwigs-Universit¨at Freiburg unter Anleitung von Dr. Sebastian Riedel angefertigt. Bei ihm m¨ochte ich mich fur¨ die interessante Themenstellung, das Interes- se am Fortschritt der Arbeit, seine große Hilfsbereitschaft bei quantenchemischen und experimentellen Fragen, sowie die nette Betreuung im Allgemeinen bedanken. Prof. Ingo Krossing danke ich fur¨ die Ubernahme¨ des Korreferates, die ebenfalls gute Betreuung sowie die Aufnahme in seinen Arbeitskreis. Außerdem bedanke ich mich bei allen weiteren Personen, die zum Gelingen dieser Arbeit beigetragen haben: Heike Haller, Felix Brosi, Robin Bruckner¨ und Thomas Vent-Schmidt sowie allen Mit- gliedern der Arbeitskreise Krossing, Knapp, Kurz, Hillebrecht und R¨ohr fur¨ die angenehme Arbeitsatmosph¨are und den fachlichen Austausch, "meinen" Mitarbeiterpraktikanten und Bachelorstudenten Andreas Sch¨oppach, Patrick Muller,¨ Thomas Vent-Schmidt, Marc J¨ager und Benjamin Freyh fur¨ die Mitarbeit an verschiedenen Projekten, Prof. Lester Andrews fur¨ die interessanten Kooperationsprojekte sowie seine große Hilfe beim L¨osen von experimentellen Problemen und schließlich Vera Bruksch und Brigitte J¨orger fur¨ das unkomplizierte Erledigen von organisatorischen und burokratischen¨ Aufgaben. Ganz besonderer Dank gilt weiterhin den Mitarbeitern der Feinmechanischen Werkstatt des chemischen Laboratoriums, insbesondere Reinhard Tomm, Christian Roll und Markus Melder, welche am Aufbau der neuen Matrixanlage wesentlich beteiligt waren und ohne deren Beitrag der experimentelle Teil dieser Arbeit nicht m¨oglich gewesen w¨are. Prof. Harald Hillebrecht und der Deutschen Forschungsgemeinschaft danke ich fur¨ finan- zielle Unterstutzung.¨ Table of Contents List of Tables XI List of Figures XIII List of Abbreviations XV 1 Introduction 1 2 Background 3 2.1 Stabilisation of high oxidation states . .3 2.2 Internal reduction reactions . .4 2.3 Assignment of oxidation states . .5 2.4 The highest oxidation states of the transition metals . .6 2.5 Transition metal hexafluorides . .7 3 Methods 9 3.1 The matrix isolation technique . .9 3.1.1 Generation of the matrix sample . .9 3.1.2 Matrix IR spectroscopy . 10 3.1.3 Matrix host materials . 10 3.1.4 Reactions in the matrix . 11 V VI TABLE OF CONTENTS 3.2 Quantum-chemical description of molecules containing high-valent transition metals ...................................... 11 3.2.1 Electron correlation . 12 3.2.2 Relativistic effects . 16 3.2.3 Assignment of oxidation states . 19 4 Setup of the new matrix isolation apparatus 21 4.1 Cold head and cold window . 21 4.2 Thematrixchamber .............................. 22 4.3 The high vacuum system . 23 4.4 Laser ablation of metals . 23 4.5 The spectrometer . 24 5 Fluorides of the 3d transition metals 25 5.1 Chromiumfluorides............................... 26 5.1.1 Structures................................ 27 5.1.2 Thermochemistry . 30 5.1.3 Vibrational frequencies . 31 5.1.4 Matrix isolation experiments . 33 5.1.5 Summary ................................ 38 5.2 Manganese fluorides . 39 5.2.1 Structures................................ 39 5.2.2 Thermochemistry . 42 5.2.3 Vibrational frequencies . 43 5.2.4 Summary ................................ 44 5.3 Ironfluorides .................................. 44 5.3.1 Structures................................ 45 5.3.2 Thermochemistry . 47 TABLE OF CONTENTS VII 5.3.3 Matrix isolation experiments . 48 5.3.4 Vibrational frequencies . 51 5.3.5 Summary ................................ 53 5.4 Cobalt fluorides . 53 5.4.1 Structures................................ 54 5.4.2 Thermochemistry . 55 5.4.3 Vibrational frequencies . 56 5.4.4 Summary ................................ 57 5.5 Conclusion and outlook . 58 5.6 Experimental and computational details . 59 5.6.1 Matrix isolation experiments . 59 5.6.2 Quantum-chemical calculations . 59 6 Oxides of Rh, Ir and Au 61 6.1 Rhodiumtetroxide ............................... 61 6.1.1 Matrix isolation experiments . 62 6.1.2 Structures................................ 62 6.1.3 Thermochemistry . 65 6.1.4 Vibrational frequencies . 65 6.1.5 Summary ................................ 68 6.2 The iridium tetroxide cation . 68 6.2.1 Structures................................ 68 6.2.2 Thermochemistry . 70 6.2.3 Vibrational frequencies . 71 6.2.4 Summary ................................ 71 6.3 Thegolddioxidecation............................. 73 6.3.1 Structures................................ 73 VIII TABLE OF CONTENTS 6.3.2 Thermochemistry . 76 6.3.3 Vibrational frequencies . 77 6.3.4 Summary ................................ 79 6.4 Conclusion and outlook . 79 6.5 Computational details . 80 7 Oxide fluorides of Hg, Au, U and Th 81 7.1 Mercuryoxidefluorides............................. 82 7.1.1 Matrix isolation experiments . 82 7.1.2 Structures................................ 83 7.1.3 Thermochemistry . 85 7.1.4 Vibrational frequencies . 85 7.1.5 Summary ................................ 85 7.2 Goldoxidefluorides............................... 87 7.2.1 Structures................................ 87 7.2.2 Thermochemistry . 90 7.2.3 Vibrational frequencies . 91 7.2.4 Summary ................................ 92 7.3 Thorium and uranium oxide difluoride . 92 7.3.1 Matrix isolation experiments . 93 7.3.2 Structures and bonding . 93 7.3.3 Vibrational frequencies . 97 7.3.4 Summary ................................ 97 7.4 Conclusion and outlook . 97 7.5 Computational details . 98 8 Conclusion 101 TABLE OF CONTENTS IX Appendix 103 A Technicaldrawings ............................... 103 X TABLE OF CONTENTS List of Tables 5.1 Structural parameters of molecular chromium fluorides . 28 5.2 Calculated thermochemistry of CrF6 and CrF5 ................ 30 5.3 Wavenumbers of the Cr{F stretching modes of molecular chromium fluorides 31 5.4 Isotopic shifts of selected Cr{F stretching modes of CrF4, CrF5 and CrF6 . 32 5.5 Observed bands after the reaction of chromium atoms with F2 ....... 34 5.6 Structural parameters of molecular manganese fluorides . 41 5.7 Calculated thermochemistry of molecular manganese fluorides . 42 5.8 Wavenumbers of the Mn{F stretching modes of molecular manganese fluorides 43 5.9 Structural parameters of molecular iron fluorides . 46 5.10 CV correlation effects on the calculated bond lengths of FeF2, FeF3 and FeF4 46 5.11 Calculated thermochemistry of molecular iron fluorides . 47 5.12 Wavenumbers of the Fe{F stretching modes of molecular iron fluorides . 51 5.13 CV correlation effects on the calculated wavenumbers of FeF2, FeF3 and FeF4 52 5.14 Isotopic shifts of selected Fe{F stretching modes of molecular iron fluorides 52 5.15 Structural parameters of molecular cobalt fluorides . 55 5.16 Calculated thermochemistry of molecular cobalt fluorides . 56 5.17 Wavenumbers of the Co{F stretching modes of molecular cobalt fluorides . 57 6.1 Structural parameters of molecular rhodium oxides . 64 6.2 Calculated thermochemistry of RhO4 and RhO2 ............... 65 XI XII LIST OF TABLES 6.3 Selected wavenumbers of molecular rhodium oxides . 66 6.4 Isotopic shifts of selected modes of molecular rhodium oxides . 67 + 6.5 Structural parameters of different [IrO4] isomers and their argon complexes 69 + 6.6 Calculated thermochemistry of [IrO4] and its argon complexes . 70 + 6.7 Calculated argon complexation energies of the different [IrO4] isomers . 71 + 6.8 Selected wavenumbers of different [IrO4] isomers . 72 + 6.9 Selected wavenumbers of the argon complexes of the different [IrO4] isomers 72 + 6.10 Structural parameters of different [AuO2] isomers and their argon complexes 74 6.11 Calculated energy differences between different electronic states of [OAuO]+ 75 1 + 6.12 Calculated thermochemistry of [Au(η -O2)] and its argon complexes . 76 + 6.13 Calculated argon complexation energies of the different [AuO2] isomers . 77 + 6.14 Selected wavenumbers of different [AuO2] isomers . 78 + 6.15 Selected wavenumbers of the argon complexes of the different [AuO2] isomers 78 7.1 Structural parameters of molecular mercury oxide fluorides . 84 7.2 Calculated thermochemistry of molecular mercury oxide fluorides . 85 7.3 Wavenumbers of the stretching modes of molecular mercury oxide fluorides 86 7.4 Isotopic shifts of selected stretching modes of FHgOF and OHgF . 86 7.5 Structural parameters of molecular gold oxide fluorides . 89 7.6 Calculated thermochemistry of molecular gold oxide fluorides . 90 7.7 Calculated argon complexation energies of AuF, AuO and AuOF . 90 7.8 Wavenumbers of the stretching modes of molecular gold oxide fluorides . 91 7.9 Structural parameters of ThOF2 and UOF2 ................. 94 7.10 NBO analysis of the U{O and Th{O bonds in UOF2 and ThOF2 ...... 96 7.11 Wavenumbers of the stretching modes of ThOF2 and UOF2 ......... 97 List of Figures 2.1 The highest oxidation states of the transition metals in homoleptic fluoride andoxidecomplexes ..............................6 3.1 Schematic
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