Controlled Redox Chemistry at Cerium within a Tripodal Nitroxide Ligand Framework

Ligand reorganization has been shown to have a profound effect on the outcome of cerium redox chemistry. Through the use of a tethered, tripodal, trianionic nitroxide ligand, [((2‐ t BuNOH)C 6 H 4 CH 2 ) 3 N] 3− (TriNO x 3− ), controlled redox chemistry at cerium was accomplished, and typically reactive complexes of tetravalent cerium were isolated. These included rare cationic complexes [Ce(TriNO x )thf][BAr F 4 ], in which Ar F =3,5‐(CF 3 ) 2 ‐C 6 H 3 , and [Ce(TriNO x )py][OTf]. A rare complete Ce–halide series, Ce(TriNO x )X, in which X=F − , Cl − , Br − , I − , was also synthesized. The solution chemistry of these complexes was explored through detailed solution‐phase electrochemistry and 1 H NMR experiments and showed a unique shift in the ratio of species with inner‐ and outer‐sphere anions with size of the anionic X − group. DFT calculations on the series of calculations corroborated the experimental findings.