Molecular Hydrogen Complexes. Preparation and Reactivity of New Ruthenium(II) and Osmium (II) Derivatives and a Comparison along the Iron Triad

Molecular hydrogen complexes [MH(η2-H2)P4]BF4[M = Ru, Os; P = PhP(OEt)2, P(OEt)3, P(OMe)3] were prepared by allowing the MH2P4hydrides to react with HBF4·Et20 at −80 °C in ethanol or diethyl ether. Their characterization by variable-temperature 1H and 31P NMR data, T1, measurements, and JHDvalues is reported. The influence of the phosphite ligand and the central metal (Fe, Ru, Os) on the properties of the complexes is also discussed. Monohydrido complexes of the type [MHLP4]BPh4[L = CO, 4-CH3C6H4NC, 4-CH3C6H4CN; P = PhP(OEt)2, P(OEt)3] were obtained by substitution of dihydrogen with the appropriate ligand. The reactions of arenediazonium cations with the molecular hydrogen and dihydride RuH2P4complexes were examined, and the syntheses of pentacoordinate [Ru(ArN=NH)P4](BPh4)2and [Ru(ArN2)P4]BPh4complexes and octahedral [RuH-(ArN=NH)P4]BPh4and [Ru(ArN=NH)2P4](BPh4)2derivatives were achieved. The characterization of the complexes by IR and 1H and 31P NMR spectra is reported. © 1990, American Chemical Society. All rights reserved.