Synthesis of a terminal Ce(iv) oxo complex by photolysis of a Ce(iii) nitrate complex† †Electronic supplementary information (ESI) available: Further experimental details, figures, spectral, electrochemical, and crystallographic data for 1–4. CCDC 1569781–1569784. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc03715e Click here for additional data file. Click here for additional data file.

ion. To test the thermodynamic favourability of the proposed 1e reduction to form 4, we investigated its electrochemistry by cyclic voltammetry. The cyclic voltammogram of 4 in THF reveals a redox feature centred at 0.53 V at 200 mV s 1 (vs. Fc/Fc; see Fig. S23 in ESI†). This feature is marked by a large difference between the potentials of the oxidation and reduction peaks (i.e., 0.72 V at 200 mV s ), suggestive of an ECE-type process. While the potential of this feature is comparable to those previously reported for cerium complexes with similar ligand frameworks, including [Ce(F)(NR2)3] ( 0.56 V), [Ce(Cl)(NR2)3] ( 0.30 V) and [Ce(Br)(NR2)3] ( 0.31 V), its electrochemical irreversibility suggests that [Ce(OSiMe3)(NR2)3] is not particularly stable. Therefore, complex 4 may not be formed via a straightforward 1e reduction of a [Ce(OSiMe3)(NR2)3] intermediate. Instead, the cyclic voltammetry data may be evidence for a concerted $SiMe3 abstraction by 2 to form 4. A similar $SiMe3 abstraction by the uranyl fragment has been reported by Arnold and coworkers.