Synthesis and Spectroscopic and Computational Characterization of the Chalcogenido-Substituted Analogues of the Uranyl Ion, [OUE]²⁺ (E = S, Se)

Addition of E (E = 0.125S8, Se) to [Cp*2Co]­[U­(O)­(NR2)3] (R = SiMe3) in THF results in the isolation of the chalcogen-substituted uranyl analogues [Cp*2Co]­[U­(O)­(E)­(NR2)3] [E = S (1), Se (2)] in good yields. Similarly, addition of 1 equiv of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) to [Cp*2Co]­[U­(O)­(NR2)3] affords the uranyl complex [Cp*2Co]­[UO2(NR2)3] (3). All of the complexes were fully characterized, including analysis by X-ray crystallography. They were also analyzed by density functional theory calculations to probe the changes in the U–E bond as group 16 is descended.