Two complexes derived from the reaction of M3(CO)12 clusters (M = Ru,Os) with the 9‐(triphenylphosphonio)fluorenide ylide: tricarbonyl[9‐(triphenylphosphonio)fluorenylidene]ruthenium and nonacarbonyl‐μ3‐fluorenylidene‐μ2‐hydrido‐triangulo‐triosmium(III)

Tricarbonyl9‐(triphenylphosphonio)fluorenylidene]ruthenium, Ru(C₃₁H₂₁P)(CO)₃], (I), is mononuclear, consisting of a single Ru centre, to which three carbonyl units and a chelating μ₃‐9‐(triphenylphosphonio)fluorenide ylide bind to generate a distorted octahedral RuC₆ core. Nonacarbonyl‐μ₃‐fluorenylidene‐μ₂‐hydrido‐triangulo‐triosmium(III), Os₃H(C₁₃H₇)(CO)₉], (II), is trinuclear and presents a triangular triosmium core, nine carbonyl ligands and one fluorenylidene ligand. Two of the Os^III centres present a highly distorted hexacoordinated Os(Os₂C₄) core and are in turn bridged by a hydride ligand. The remaining Os^III cation is octacoordinated, with an Os(Os₂C₆) nucleus. The crystal structures of both compounds are the result of nondirectional forces, much resembling the packing of weakly interacting quasi‐spherical units, viz. the molecules themselves in (I) and centrosymmetric π–π‐bonded dimers in (II).