Treatment of (PPN)3[P3(NH)3O6] (PPN = (PPh3)2N+) with [(η6-C6H6)RuCl(μ-Cl)]2 in CH2Cl2 at room temperature gives the anionic ruthenium-trimetaphosphimato complex (PPN)[(η6-C6H6)-Ru{P3(NH)3O6}] (1) in 83% yield. By similar reactions the Cp∗Rh (Cp∗ = η5-C5Me5) complex (PPN)[Cp∗Rh{P3(NH)3O6}] (3) and the Cp∗Ir complex (PPN)[Cp∗Ir{P3(NH)3O6}] (4) are synthesized from [Cp∗MCl(μ-Cl)]2 (M = Rh, Ir) in high yields. X-ray diffraction studies of 1•0.5CH2Cl2, 3•CH2Cl2 and 4•CH2Cl2 have shown that these complexes adopt a three-legged piano-stool structure in the solid state, where the three axial oxygen atoms of the trimetaphosphimato ligand occupy the fac positions. The structure of 1•0.5CH2Cl2 has been compared in detail with that of the corresponding cyclotriphosphato complex (PPN)[(η6-C6H6)Ru(P3O9)] (2). The electrochemical behavior of these complexes is also described.【査読有】