The Selective Oligomerization of Ethylene Using Chromium Diphosphine Catalysts and The Synthesis and Reactivity of Group 7 Carbonyl Derivatives Relevant to Synthesis Gas Conversion

2 Introduction 3 Results and Discussion 17 A Chromium Diphosphine System for Selective and Catalytic Ethylene Oligomerization 17 Synthesis of PNP Ligands with Ether Groups Tethered to Nitrogen 17 Preparation and Characterization of PNP Chromium Complexes 18 Catalytic Runs at 1 atm of Ethylene Using Precatalysts 21-24 24 Catalytic Runs at Higher Pressures of Ethylene 28 Role of the Ether Tether in Increasing Catalyst Stability 33 Modification of the Pendant Donor 36 Mechanistic Insight Obtained from the Product Mixture 39 Temperature Dependence 42 Investigating Catalyst Decomposition 43 Solvent Effects in the Chromium-Catalyzed Ethylene Oligomerization 49 The Effect of the co-Catalyst on Activity and Selectivity 61