Syntheses and crystal structures of the ruthenium carbidocarbonyl clusters [Ru5C(CO)11(µ-Br)2(η3-C3H5)(µ-η3-C3H5)], [Ru5C(CO)13I(µ-I)(µ-η2-COMe)]–, [Ru5C(CO)14(µ-Br)2] and [Ru6C(CO)16(µ-Br)]– with novel metal frameworks

Abstract

The reaction of the octahedral cluster anion [N(PPh₃)₂][Ru₆C(CO)₁₅(µ-η³-C₃H₅)] with allyl bromide at 115 °C afforded the pentanuclear cluster [Ru₅C(CO)₁₁(µ-Br)₂(η³-C₃H₅)(µ-η³-C₃H₅)] containing a square-based pyramidal geometry in which two adjacent apical-to-basal edges are cleaved and replaced by two symmetrically bridging Br atoms. One allyl ligand bridges a Ru–Ru edge of the square base in a µ-η³ fashion, while the other allyl group co-ordinates to the apical Ru atom as a simple η³ ligand. The reaction of the octahedral cluster anion [N(PPh₃)₂][Ru₆C(CO)₁₆(Me)] with methyl iodide in CH₂Cl₂ at 150°C gave the cluster [N(PPh₃)₂][Ru₅C(CO)₁₃I(µ-I)(µ-η-²-COMe)] displaying a square-based pyramidal geometry in which two opposite apical-to-basal edges are cleaved and bridged by a µ-η² acetyl group and an I atom. The complex [N(PPh₃)₂]₂[Ru₆C(CO)₁₆] reacted with benzyl bromide at 60 °C to give the novel octahedral cluster [N(PPh₃)₂][Ru₆C(CO)₁₆(µ-Br)] in which one edge of the metal framework is cleaved and symmetrically bridged by a Br atom. Further reaction with benzyl bromide at 130 °C led to [Ru₅C(CO)₁₄(µ-Br)₂], which exhibits the same metal geometry as the iodide with two Br atoms symmetrically bridging two opposite apical-to-basal edges of the square-based pyramidal geometry.