MOLECULAR-ORGANIZATION AND DYNAMIC BEHAVIOR OF ARENE CLUSTER COMPLEXES IN THE SOLID-STATE - CRYSTAL-STRUCTURES OF [OS4H2(CO)10(ETA-6-C6H5ME)], [OS4H2(CO)10(ETA-6-C6H4ME2)] AND [RU6C(CO)14(ETA-6-C6H3ME3-1,3,5)]

The molecular organization in crystals of the tetranuclear arene clusters [Os4H2(CO)10(eta-6-arene)] (arene = C6H6, C6H5Me, C6H4Me2-o or -m) and of the hexanuclear species [Ru6C(CO)14(eta-6-C6H5Me)], [Ru6C(CO)14(eta-6-C6H3Me3-1,3,5)] and [Ru6C(CO)11(mu-3-eta-2:eta-2:eta-2-C6H6) (eta-6-C6H6)] has been investigated by means of packing potential-energy calculations and computer graphics analysis. Attention is focused on the relationship between the shape, size and geometry of these molecules and the ease of reorientational motion of the arene fragments in the solid state. The crystal structures of [Os4H2(CO)10(eta-6-C6H5Me)] and [Os4H2(CO)10(eta-6-C6H4Me2)] have been determined by X-ray diffraction and that of [Ru6C(CO)14(eta-6-C6H3Me3-1,3,5)] redetermined.