Tetravalent cerium pseudohalide complexes supported by the Kläui tripodal ligand [Co(η5-C5H5){P(O)(OEt)2}3]−

Abstract

Cerium(IV) pseudohalide complexes supported by the Kläui tripodal ligand [Co(η⁵-C₅H₅){P(O)(OEt)₂}₃]⁻ (L_OEt⁻) have been synthesized and structurally characterized. The treatment of [Ce^IV(L_OEt)₂Cl₂] (1) with 2 equivalents of [AgX] in acetonitrile afforded [Ce^IV(L_OEt)₂X₂] [X⁻ = NCS⁻ (2), N₃⁻ (3), F⁻ (4)]. The reaction of 1 with [AgCN] in dichloromethane at −40 °C led to formation of a bimetallic Ce^IV/Ag^I cyanide complex that decomposed in solution at room temperature. In the presence of BPh₃, 1 reacted with [AgCN] to yield the cyanoborate complex [Ce^IV(L_OEt)₂(NCBPh₃)₂] (6) that is stable in solution. The chlorination of [Ce^III(L_OEt)₂(NO₃)] with PhICl₂ afforded [Ce^IV(L_OEt)₂(NO₃)Cl] (7) that reacted with [AgCN] to yield the heterometallic Ce^IV/Ag^I cyanide complex [{Ce(L_OEt)₂(NO₃)}₂{μ-Ag(CN)₂}][AgCl₂] (8). The reaction of [Ce^IV(L_OEt)Cl₃] with [AgN₃] afforded the tetranuclear Ce^IV oxo azido cluster [Ce₄(L_OEt)₄(μ₄-O)(μ₂-O)₂(μ₂-N₃)₆] (9). The structures of complexes 2, 3, 6 and 9 have been established by X-ray crystallography.