Multielectron chemistry with a redox active uranium complex

Dennis P Cladis, Purdue University

Abstract

The synthesis and reactivity of uranium complexes supported by the redox active pyridine diimine {PDI = 2,6-bis-[2,4,6-trimethylphenyl N=C(Me)] 2 pyridine} ligand are reported. The tetravalent uranium complex Cp*U(PDI)(THF) (1, Cp* = 1,2,3,4,5-pentamethylcyclopentadienide; THF = tetrahydrofuran) contains a triply reduced PDI ligand, which was confirmed by the molecular structure and spectral characterization. Magnetism studies yielded a magnetic moment of 2.3 &mgr;eff. By taking advantage of the electrons stored in the redox active ligand, the ability of 1 to facilitate mononuclear, multielectron chemistry was explored. 1 was treated with pyridine-N-oxide to form the hexavalent uranyl complex, Cp*U(O)2(PDI) (2), with a singly reduced PDI ligand. The bond distances obtained by X-ray crystallography support the assignment of the U(VI) oxidation state. Additionally, the treatment of 1 with azobenzene forms a pentavalent trans bis imido complex Cp*U(=NPh)2(PDI) (3). In contrast to 2, 3 contains one f-electron and a neutral PDI ligand, supported by the 1H NMR spectrum and the bond distances in the molecular structure. The functionalization of 2 and 3 was attempted with trimethyl silyl and carbonyl containing molecules. The results of these experiments and the full characterization of 1, 2, and 3 are presented.

Degree

M.S.

Advisors

Bart, Purdue University.

Subject Area

Chemistry|Inorganic chemistry

COinS