Metallkomplexe von Farbstoffen. VI. Phosphan-Nickel-, Palladium- und Platin-Komplexe sowie Pentamethyl-cyclopentadienyl-Rhodium- und Iridium-Komplexe von Bis(2-hydroxyaryl)azo-Farbstoffen

Metal Complexes of Dyes. Phosphine-Nickel, Palladium, Platinum Complexes and Pentamethylcyclopentadienyl Rhodium and Iridium Complexes of 2,2′-Dihydroxyazoarenes The terdentate dianions of 2,2′-dihydroxyazobenzene (L¹H), 1-(2-hydroxy-4-nitrophenylazo)-2-naphthol (L²H), 1-(2-hydroxy-5-nitrophenylazo)-2-naphthol (L³H) and 1-phenyl-3-methyl-4-(2-hydroxy-5-nitrophenylazo)-5-pyrazolone (L⁴H) form with chloro bridged complexes (R₃P)MCl₂]₂ (M = Pd, Pt; R = Ph, nBu), (n⁵-C₅Me₅)MCl₂]₂ (M = Rh, Ir) and with (nBu₃P)₂NiCl₂ the metal dye complexes (R₃P)ML (M = Ni, Pd, Pt) and (C₅Me₅)ML (M = Rh, Ir). The structures of (Ph₃P)PtL¹ and (nBu₃P)PdL³ have been determined by X-ray diffraction. For the complexes (n⁵-C₅Me₅)ML (M = Rh, Ir) with asymmetric metal centers two diastereoisomers are detected by nmr spectroscopy which points to the ?hydrazone”? form of the azo ligand with a pyramidalized N-atom.