Arene bridged diuranium compounds supported by amide and ketimide ligands
Chapter 1: The Intriguing Geometric and Electronic Structure of Arene-Bridged Diuranium Tetrakisamido Complexes The focus of this chapter is to characterize and contextualize the bridged arene complex ( -toluene)U2(N[t-Bu]Ar)4 (lb2-gl-toluene, Ar = 3,5-C6H3Me2). To do so, lb2-g-toluene is compared extensively with the mononuclear complexes (THF)U(N[1Ad]Ar)3 (2a-THF, THF = tetrahydrofuran), JIU(N[t-Bu]Ar)3 (la-I), IU(N['Ad]Ar)3 (2a-I), and Me3SiNU(N[1Ad]Ar)3 (2a- NSiMe3). In order to understand the properties of a unique compound such as lb2-pg-toluene, the rest of the series is based on classical uranium amide compounds. The syntheses, structures (X-ray crystal structures and solution behavior based on variable temperature, VT, NMR data), spectroscopic (X-ray absorption near-edge structure, XANES, and electronic absorption - UV- vis-NIR) and magnetic properties are discussed and interpreted with reference to results of density functional theory (DFT) calculations performed on model compounds. Reactivity studies of lb2-p-toluene are then presented and analyzed. Chapter 2: Arene Bridged Diuranium Complexes Supported by a Ketimide Ligand: Even and Odd Electron Redox Pairs The ketimide ligand NC[t-Bu]Mes (Mes = 2,4,6-C6H2Me3) employed in the present study allows for retention of three supporting ligands per uranium, giving rise to a three-legged piano stool geometry, and it also allows for incorporation of potassium ions as tight ion pairs. The generality of such a ligand is well supported by the existence of the two types of compounds M2(g-arene)U2(NC[t-Bu]Mes)6 (M2-32-g-arene, M = Na, K) and K-32-pt-arene, when the arene is naphthalene, biphenyl, trans-stilbene, or p-terphenyl
Thesis, Dissertation, English, ©2003
©2003