Unexpected fragmentations of triphosphaferrocene – formation of supramolecular assemblies containing the (1,2,4-P3C2Mes2)− ligand

Abstract

While reacting the sterically demanding triphosphaferrocene [Cp*Fe(η⁵-P₃C₂Mes₂)] (1) with Cu(I) halides, the sandwich complex undergoes an unprecedented fragmentation into decamethylferrocene, FeX₂ (X = Cl, Br, I) and [P₃C₂Mes₂]⁻ units. Subsequently, these phospholyl ligands act as versatile, negatively charged building blocks for the formation of supramolecular aggregates representing the monomeric, dimeric and polymeric (1D and 2D) coordination compounds [(P₃C₂Mes₂)₂{Cu₇(CH₃CN)₇(μ₄-X)(μ₃-X)₂(μ-X)}{Cu₂(μ₂-X)₂X}{Cu(CH₃CN)(μ₂-X)}]₂·6CH₃CN (2·6CH₃CN: X = Cl, 3·6CH₃CN: X = Br), [(P₃C₂Mes₂)₂{Cu(CH₃CN)}₆(μ-Br)₂(μ₃-Br)₂{Cu(CH₃CN)₂Br}₂]·CH₃CN (4a·CH₃CN), [(P₃C₂Mes₂)₄{Cu₅(CH₃CN)₅(μ₂-Br)}{Cu(CH₃CN)₂CuBr₂}₂{Cu(CH₃CN)₂}]_n⁺[CuBr₂]_n⁻·2CH₃CN (5·2CH₃CN), [(P₃C₂Mes₂){Cu(CH₃CN)(μ-I)}₄{Cu(CH₃CN)₃}]·0.5C₇H₈·2.5CH₃CN (6·0.5C₇H₈·2.5CH₃CN), [(P₃C₂Mes₂)Cu₇(CH₃CN)₄(μ₄-I)₂(μ₃-I)₂(μ-I)₂]_x·2C₇H₈ (7·2C₇H₈), [(P₃C₂Mes₂){Cu(CH₃CN)₃}₂{Cu(μ-I)}₆]·0.5CH₂Cl₂·3CH₃CN (8·0.5CH₂Cl₂·3CH₃CN) and [Cp*Fe(CH₃CN)₃]_n⁺[(P₃C₂Mes₂)₂{Cu(CH₃CN)₂}{Cu(μ-I)}₆]_n⁻·0.6CH₂Cl₂ (9·0.6CH₂Cl₂) with rather non-typical structural motifs within the large varieties of copper halide chemistry. Besides the X-ray structural analyses the obtained assemblies were also characterized in solution in which they undergo fragmentation and re-aggregation processes.