REACTIVITY AND COORDINATION STUDIES OF DIPHOSPHACYCLOBUTADIENE SANDWICH ANIONS Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften DR. RER. NAT. am Institut für Anorganische Chemie der Fakultät für Chemie und Pharmazie der Universität Regensburg vorgelegt von CHRISTIAN RÖDL aus Vilsbiburg Regensburg 2019 Der experimentelle Teil der vorliegenden Arbeit wurde von Januar 2015 bis November 2018 unter Anleitung von Prof. Dr. Robert Wolf am Institut für Anorganische Chemie der Universität Regensburg angefertigt. Diese Arbeit wurde angeleitet von: Prof. Dr. Robert Wolf Promotionsgesuch eingereicht am: 02.05.2019 Tag der mündlichen Prüfung: 03.07.2019 Promotionsausschuss: Vorsitz: Prof. Dr. Alkwin Slenczka Erstgutachter: Prof. Dr. Robert Wolf Zweitgutachter: Prof. Dr. Manfred Scheer Dritter Prüfer: Prof. Dr. Frank-Michael Matysik PROLOGUE PROLOGUE This thesis reports on the synthesis and characterization of mono-, di-, and oligonuclear cobalt complexes with diphosphacyclobutadiene and diphosphacyclobutene ligands. Chapter 1 reviews the chemistry of transition metal phosphaalkyne and diphosphacyclobutadiene complexes. Besides the synthesis and structural motifs of diphosphacyclobutadiene complexes, this chapter also deals with the coordination properties of such species. In chapters 2 and 3, the functionalization of the diphosphacyclobutadiene ligand is discussed. Chapters 4 and 5 describe coordination studies, which have resulted in the synthesis and characterization of numerous new di- and oligonuclear complexes with diphosphacyclobutadiene ligands. Chapter 6 reports on the thermal properties as well as the potential application of complexes with diphosphacyclobutadienes and other phosphorus containing ligands in atomic layer deposition. The final chapter 7 summarizes the results of this thesis and gives a brief outlook. TABLE OF CONTENTS TABLE OF CONTENTS 1 THE CHEMISTRY OF PHOSPHAALKYNE AND DIPHOSPHACYCLOBUTADIENE COMPLEXES ................................................................................................................ 1 1.1 Introduction .............................................................................................................................. 1 1.1.1 Historical Development of Phosphaalkyne Chemistry ............................................................... 1 1.1.2 The Coordination Chemistry of Phosphaalkynes ....................................................................... 2 1.2 Transition Metal-Mediated Oligomerization ............................................................................. 3 1.2.1 Dimerization and Trimerization .................................................................................................. 3 1.2.2 Access to further Phosphaorganometallic Ligands by Phosphaalkyne Oligomerization ............ 6 1.2.3 Coordination Compounds and Metal Aggregates ...................................................................... 7 1.3 Conclusion .............................................................................................................................. 10 1.4 References .............................................................................................................................. 12 2 FUNCTIONALIZATION OF 1,3-DIPHOSPHACYCLOBUTADIENE COBALT COMPLEXES VIA SI‒P BOND INSERTION ........................................................................................ 15 2.1 Introduction ............................................................................................................................ 17 2.2 Results and Discussion ............................................................................................................ 19 2.2.1 Synthesis and Structural and Spectroscopic Characterization of Silylated 1,3-Diphosphacyclobutadiene Complexes ............................................................................... 19 2.2.2 Functionalization Reactions by Insertion into the Phosphorus-Silicon Bond ........................... 22 2.3 Conclusion .............................................................................................................................. 28 2.4 Supporting Information .......................................................................................................... 29 2.4.1 General Procedures .................................................................................................................. 29 2.4.2 Synthesis and Characterization ................................................................................................ 29 2.4.3 31P{1H} NMR Spectra of 6−8 ...................................................................................................... 38 2.4.4 UV/Vis and IR Spectroscopy ..................................................................................................... 40 2.4.5 X-ray Crystallography ............................................................................................................... 46 2.5 References .............................................................................................................................. 52 3 1,3-DIPHOSPHACYCLOBUTENE COBALT COMPLEXES ................................................ 55 TABLE OF CONTENTS 3.1 Introduction ........................................................................................................................... 57 3.2 Results and Discussion ............................................................................................................ 59 3.2.1 Reaction of [Co(P2C2tBu2)H] with Lithium Organyls ................................................................. 59 3.2.2 Reaction of [Co(P2C2tBu2)H] with Grignard Reagents ............................................................... 65 3.2.3 Computational Studies ............................................................................................................. 65 3.2.4 Synthesis of 5 by Trimethylsilylation of 1 ................................................................................. 67 3.3 Conclusion .............................................................................................................................. 69 3.4 Supporting Information .......................................................................................................... 70 3.4.1 General Procedures .................................................................................................................. 70 3.4.2 Synthesis and Characterization ................................................................................................ 70 3.4.3 Reaction of [Co(P2C2tBu2)2H] with Grignard Reagents ............................................................. 73 3.4.4 31P{1H} NMR Spectra of 1-3, and 5 ............................................................................................ 74 3.4.5 Variable Temperature and 2D Correlation NMR Spectroscopy ................................................ 78 3.4.6 Cyclic Voltammetry ................................................................................................................... 84 3.4.7 X-ray Crystallography................................................................................................................ 85 3.4.8 Theoretical Investigations ........................................................................................................ 88 3.5 References .............................................................................................................................. 91 4 FLEXIDENTATE COORDINATION BEHAVIOR AND CHEMICAL NON-INNOCENCE OF A BIS(1,3-DIPHOSPHACYCLOBUTADIENE) SANDWICH ANION .................................... 95 4.1 Introduction ........................................................................................................................... 97 4.2 Results and Discussion .......................................................................................................... 100 4.2.1 Reaction of [K(thf)2{Co(P2C2tBu2)2}] with [Ni2Cp3]BF4 ............................................................. 100 4.2.2 Reaction of [K(thf)2{Co(P2C2tBu2)2}] with [Cp*RuCl]4 .............................................................. 104 4.2.3 Reaction of [K(thf)2{Co(P2C2tBu2)2}] with [RhCl(cod)]2 ............................................................ 107 4.2.5 Reaction of [K(thf)2{Co(P2C2tBu2)2}] with cis-PdCl2(PPh3)2 ...................................................... 109 4.2.6 Reaction of [K(thf)2{Co(P2C2tBu2)2}] with HgCl2 ...................................................................... 113 4.3 Conclusion ............................................................................................................................ 117 4.4 Supporting Information ........................................................................................................ 118 4.4.1 General Procedures ................................................................................................................ 118 4.4.2 Optimized Synthesis of [K(thf)1.75{Co(P2C2tBu2)2}] (A) ............................................................ 118 4.4.3 Synthesis of [CpNi{Co(P2C2tBu2)2}(thf)] (2) ............................................................................. 118 4 4 4.4.4 Synthesis of [Co(η -CpNi{1,3-P2C2tBu2-κP,κC})(η -1,3-P2C2tBu2)] (3) ...................................... 119 TABLE OF CONTENTS 4 2 4 4.4.5 Synthesis of [Co(η -CpNi{1,4-P2C2tBu2-κ P,P})(η -1,3-P2C2tBu2)] (4) .....................................