Multi‐electron Oxidation of Ce(III) Complexes Facilitated by Redox‐Active Ligands

Abstract

AbstractA family of cerium complexes featuring a redox‐active ligand in different oxidation states has been synthesized, including the the iminosemiquinone (isq)1− compound, Ce(dippisq)3 (1‐Ceisq), and the amidophenolate (ap)2− species CeIII(dippap)3K3 (2‐Ceap), [CeIII(dippap)3K][K(18‐c‐6)]2 (2‐Ceap 18c6), and [CeIII(dippap)3K][K(15‐c‐5)2]2 (2‐Ceap 15c5). Treating 2‐Ceap 15c5 with dioxogen furnishes the cerium(IV) derivative [CeIV(dippap)3][K(15‐c‐5)2]2 (3‐Ceap 15c5), and an analogous synthesis can be used to generate [CeIV(dippap)3][K(crypt)]2 (3‐Ceap crypt). Similarly, addition of hexamethyldisiloxane produces an interesting bis(amidophenolate) species, [(Me3SiO)2CeIV(dippap)2][K(15‐c‐5)2]2 (4‐CeOSiMe3). Full spectroscopic and structural characterization of each derivative was performed to establish the oxidation states of both the ligands and the cerium ions.