The activation and transformations of acenaphthylene by osmium carbonyl cluster complexes

The reaction of Os3(CO)10(NCMe)2 (1) with an excess of acenaphthylene at room temperature provided the complex Os3(CO)10(μ-H)(μ–η2-C12H7) (2). Compound 2 contains a σ–π coordinated acenaphthyl ligand bridging an edge of the cluster. Compound 2 was converted to the complex Os3(CO)9(μ-H)2(μ3–η2-C12H6) (3) when heated to reflux in a cyclohexane solution. Compound 3 contains a triply bridging acenaphthyne ligand. Compound 3 reacts with acenaphthylene again at 160 °C to yield four new cluster complexes: Os4(CO)12(μ4–η2:η2-C12H6) (4); Os2(CO)6(μ–η4-C24H12) (5); Os3(CO)9(μ-H)(μ3–η4-C24H13) (6); and Os2(CO)5(μ–η4-C24H12)(η2-C12H8) (7). All compounds were characterized crystallographically. Compound 4 is a butterfly cluster of four osmium atoms bridged by a single acenaphthyne ligand. Compounds 5 and 7 are dinuclear osmium clusters containing metallacycles formed by the coupling of two equivalents of acenaphthyne. Compound 6 is a triosmium cluster formed by the coupling of an acenaphthyne ligand to an acenapthyl group that is coordinated to the cluster through a combination of σ and π-bonding.