| Sumario: | Luminescent Ce(III) complexes, Ce[N(SiMe)] (1) and [(MeSi)NC(RN)]Ce[N(SiMe)] (R = Pr, Pr; R = Cy, 1-Cy), with C and C solution symmetries display absorptive 4f → 5d electronic transitions in the visible region. Emission bands are observed at 553, 518, and 523 nm for 1, Pr, and 1-Cy with lifetimes of 24, 67, and 61 ns, respectively. Time-dependent density functional theory (TD-DFT) studies on 1 and Pr revealed the ²A excited states corresponded to singly occupied 5dz2 orbitals. The strongly reducing metalloradical character of 1, Pr, and 1-Cy in their ²A excited states afforded photochemical halogen atom abstraction reactions from sp³ and sp² C-X (X = Cl, Br, I) bonds for the first time with a lanthanide cation. The dehalogenation reactions could be turned over with catalytic amounts of photosensitizers by coupling salt metathesis and reduction to the photopromoted atom abstraction reactions.
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