Computational insights into uranium complexes supported by redox-active α-diimine ligands

The electronic structures of two uranium compounds supported by redox-active α-diimine ligands, ( ^MesDAB ^Me)2U(THF) (1) and Cp2 U( ^MesDAB ^Me) (2) ( ^MesDAB ^Me = [ArN=C(Me)C(Me)=NAr]; Ar = 2,4,6- trimethylphenyl (Mes)), have been investigated using both density functional theory and multiconfigurational selfconsistent field methods. Results from these studies have established that both uranium centers are tetravalent, that the ligands are reduced by two electrons, and that the ground states of these molecules are triplets. Energetically low-lying singlet states are accessible, and some transitions to these states are visible in the electronic absorption spectrum.