Synthesis and Characterization of Two Uranyl-Aryl "Ate" Complexes.

Reaction of [UO2 Cl2 (THF)3 ] with 3 equivalents of LiC6 Cl5 in Et2 O resulted in the formation of first uranyl aryl complex [Li(Et2 O)2 (THF)][UO2 (C6 Cl5 )3 ] ([Li][1]) in good yields. Subsequent dissolution of [Li][1] in THF resulted in conversion into [Li(THF)4 ][UO2 (C6 Cl5 )3 (THF)] ([Li][2]), also in good yields. DFT calculations reveal that the U-C bonds in [Li][1] and [Li][2] exhibit appreciable covalency. Additionally, the 13 C NMR chemical shifts for their Cipso environments are strongly affected by spin-orbit coupling-a consequence of 5f orbital participation in the U-C bonds.