Multiple Interactions Between Arenes and Metal Atoms

W(.eta.5-C5H5)[C(Ph)C(CMe3)C(Ph)]Cl2: a molecule having a localized, nonplanar, fluxional metallacyclobutadiene ring

“…And only for the unsaturated cluster H2Os3(CO)10 have several different types of capping reactions been found. 3,4 We have now observed that the saturated cluster RuCo2(CO)u,5 due to the combined lability of its Coand Ru-CO ligands, is suitable for all kinds of capping. Each of the reactions involves the attachment of a four-electron µ3 ligand on top of the RuCo2 triangle with elimination of two CO ligands.…”

“…The extension of metal complex chemistry brought about by transition-metal clusters rests on two basic cluster properties: the availability of the metal-metal bonds as reactive sites2 and the possibility of substrate binding to more than one metal atom. 3 The latter situation is quite common for µ3 substrate binding, i.e., capping of metal atom triangles.4 However capping reactions, i.e., designed attachments of µ3 ligands to metal triangles, are not common since they normally require the removal of more than one terminal ligand. And only for the unsaturated cluster H2Os3(CO)10 have several different types of capping reactions been found.…”