Arene Fragments Research Articles

Molecular and crystal structures of ruthenium and osmium arene clusters

The molecular and crystal structures of a number of ruthenium and osmium clusters of nuclearity between three and six containing arene fragments such as C6H6, C6H3Me3, C6H4Me2 and C6H5Me have been investigated. Attention has been focused on the relationship between the terminal (η6-coordination) and face-capping (μ3:η2:η2:η2-coordination) bonding modes. Empirical packing potential energy calculations have been employed to investigate the intermolecular organization in the crystal. It has been shown that the arene fragments in mono-arene clusters form ribbons, while in bis-arene clusters graphitic-like interactions throughout the crystal are established. The factors controlling the ease of arene reorientational motion in the solid state has also been investigated in relation to the shape, size and geometry of the molecules and of their interlocking modes.

Molecular organization and dynamic behaviour of arene cluster complexes in the solid state. Crystal structures of [Os4H2(CO)10(η6-C6H5Me)], [Os4H2(CO)10(η6-C6H4Me2)] and [Ru6C(CO)14(η6-C6H3Me3-1,3,5)

The molecular organization in crystals of the tetranuclear arene clusters [Os4H2(CO)10(η6-arene)](arene = C6H6, C6H5Me, C6H4Me2-o or -m) and of the hexanuclear species [Ru6C(CO)14(η6-C6H5Me)], [Ru6C(CO)14(η6-C6H3Me3-1,3,5)] and [Ru6C(CO)11(µ3-η2 : η2 : η2-C6H6)(η6-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(η6-C6H5Me)] and [Os4H2(CO)10(η6-C6H4Me2)] have been determined by X-ray diffraction and that of [Ru6C(CO)14(η6-C6H3Me3-1,3,5)] redetermined.

Synthetic studies with iron carbonyl complexes. Fragmentation of β-alcoholic tricarbonyl(diene)iron(0) complexes in the mass spectrometer; use to distinguish positional isomers

Comparison is made between the mass spectra of two isomeric tricarbonyl(cyclohexadiene)iron(0) complexes bearing 2-methyl-2-hydroxypropyl side-chains at either the 5- exo- or the 2-position. Both demonstrate a McLafferty rearrangement mechanism for an arene fragment bearing a coordinated atom of iron, but only the former shows a major competing pathway, since this involves a methylene group α to the point of attachment of the side-chain. The spectra of a variety of related complexes are discussed and a 1,3-shift of the residual C 6H 5Fe group is proposed.