Polynuclear clusters of fused-ring hydrocarbons. The synthesis and X-ray structure of [Os 4 H(CO) 9 (µ 3 -η 2 -η 2 -η 5 -C 13 H 15 )](C 13 H 15 = 1,3-diethylindenyl)

The reaction between [Os3(CO)12] and 1,3-diethylindene yields [Os4H(CO)9(µ3-η2-η2-η5-C13H15)], the structure of which is shown by X-ray crystallography to consist of a distorted tetrahedral metal framework with one triangular face coordinated by the indenyl such that the six membered ring is in the µ3-η2-η2-η2 face capping mode whilst the five membered ring is η5-bound to one of the Os atoms.