Tetravalent cerium pseudohalide complexes supported by the Kläui tripodal ligand [Co(η-CH){P(O)(OEt)}].

Cerium(iv) pseudohalide complexes supported by the Kläui tripodal ligand [Co(η-CH){P(O)(OEt)}] (L) have been synthesized and structurally characterized. The treatment of [Ce(L)Cl] (1) with 2 equivalents of [AgX] in acetonitrile afforded [Ce(L)X] [X = NCS (2), N (3), F (4)]. The reaction of 1 with [AgCN] in dichloromethane at -40 °C led to formation of a bimetallic Ce/Ag cyanide complex that decomposed in solution at room temperature. In the presence of BPh, 1 reacted with [AgCN] to yield the cyanoborate complex [Ce(L)(NCBPh)] (6) that is stable in solution. The chlorination of [Ce(L)(NO)] with PhICl afforded [Ce(L)(NO)Cl] (7) that reacted with [AgCN] to yield the heterometallic Ce/Ag cyanide complex [{Ce(L)(NO)}{μ-Ag(CN)}][AgCl] (8). The reaction of [Ce(L)Cl] with [AgN] afforded the tetranuclear Ce oxo azido cluster [Ce(L)(μ-O)(μ-O)(μ-N)] (9). The structures of complexes 2, 3, 6 and 9 have been established by X-ray crystallography.