Synthesis and characterization of dinuclear platinum group metal complexes of a hexadentate ligand α,α′-bis(bis-(2-(diphenylphosphino)ethyl)amino)-m-xylene

Article abstract of DOI:10.1016/0277-5387(95)00300-H

A number of dinuclear complexes of platinum group metal ions with a hexadentate ligand, α,α′-bis(bis-(2-(diphenylphosphino)ethyl)amino)-m-xylene (L), were synthesized. The reaction of [MCl_n(COD)], (n = 1, x = 2 when M = Rh^I and Ir^I and n = 2, x = 1 when M = Pd^II and Pt^II) with the ligand L resulted in the formation of square planar dinuclear complexes of the composition [M₂LCl₂]ⁿ⁺ (n = 0 for Rh^I and Ir^I and n = 2 for Pd^II and Pt^II). The reaction of [Pt Cl₂(COD)] with L under different experimental conditions yielded a tetranuclear complex, [Pt₄L₂Cl₄]Cl₄. The reaction of [M₂LCl₂] (M = Rh^I, Ir^I) with CO gas at ambient temperature resulted in the formation of the pentacoordinate CO adduct, [M₂LCl₂(CO)₂], with trigonal bipyramidal geometry. The reaction of [RhCl(CO)(AsPh₃)₂] and [IrCl(CO)(PPh₃)₂] with L gave complexes of the same composition as that of the CO adduct, [M₂LCl₂(CO)₂], with two isomeric forms in the case of iridium. The reaction of [Rh₂LCl₂] with AgClO₄ in acetonitrile resulted in the complete displacement of chloride, with the formation of [Rh₂L(NCCH₃)₂](ClO₄)₂. A complex of the composition [Rh₂L(PPh₃)₂](BPh₄)₂ was obtained when [RhCl(COD)]₂ was reacted with L in the presence of PPh₃ in equimolar ratio followed by addition of NaBPh₄. The reaction of hydrated iridium trichloride gave a dinuclear octahedral complex of Ir^III of composition [Ir₂LCl₆]. The geometry of the complexes was established by ³¹P{¹H} NMR spectral data.