Crystal structure and reactivity of [Ru{C6H4(NH)2-1,2}-(PPh3)3] with π-acid ligands

Abstract

The structure of the compound [Ru{C₆H₄(NH)₂-1,2}(PPh₃)₃]1 has been established from X-ray analysis by direct and Fourier methods and refined by full-matrix least squares to R= 0.071 for 3288 observed reflections: monoclinic, space group P2₁/n, a= 18.70(1), b= 13.171(6), c= 23.06(2)Å, β 99.86(6)° and Z= 4. This complex reacts with an excess of ethylene or styrene and with P(OMe)₃(molar ratio 1 : 1) in hot toluene to yield the complexes [Ru{C₆H₄(NH)₂-1,2}L(PPh₃)₂][L = C₂H₄3, CH₂CHPh 4 or P(OMe)₃, 5]. With a slight excess of the diphosphines (Ph₂P)₂X [X = CH₂(dppm), C₂H₄(dppe), 1,2-C₆H₄(dppbz), cis-C₂H₂(dppen) and C₃H₆(dppp)], refluxed in toluene, the complexes [Ru{C₆H₄(NH)₂-1,2}](PPh₃)(di-phosphine)]6–10 were obtained as dark purple crystalline solids. An excess of PMe₃ in hot toluene solutions of compound 1 afforded brown prismatic crystals of [Ru{C₆H₄(NH)₂-1,2}](PMe₃)₃]11, whereas with PEt₃ under the same conditions only partial substitution products are obtained, [Ru{C₆H₄(NH)₂-1,2}](PEt₃)(PPh₃)₂]12 and [Ru{C₆H₄(NH)₂-1,2}(PEt₃)₂(PPh₂)]13. When toluene solutions of [Ru{C₆H₄(NH)₂-1,2}](CO)(PPh₃)₂]2 were boiled with diphosphines the complexes [Ru{C₆H₄(NH)₂-1,2}(CO)(diphosphine)][dppe 14, dppbz 15, dppen 16, dppp 17 or dppb (X = C₄H₈)18] were isolated. The complex [Ru{C₆H₄(NH)₂-1,2}](CO)₂(PPh₃)]19 was also detected as a reaction product of carbonylation of toluene solutions of 1. All complexes have been characterized by elemental analysis and by IR and NMR spectroscopy.