title: (μ(1)-Methano-lato-κ(1)O)-μ(1)-methoxo-κ(1)O-(μ(2)-2-amino-1-methyl-5H-imidazol-4-one-κ(2)N:N')-hexa-carbonyl-dirhenium(I).
abstract: In the title compound, [Re(2)(CH(3)O)(2)(CO)(6)(C(4)H(6)N(3)O)], the two Re(I) atoms are linked by a methoxo and methanolato bridge, as well as by a creatinine ligand that coordinates in a bidentate fashion. Three fac-carbonyl ligands occupy the rest of the slightly distorted octa-hedral geometry around each Re(I) atom. The bridging methanolato and methoxo ligands are bent out of the Re(2)O(2) plane by 49.2 (4) and 47.8 (3)° respectively. This is normally associated with a methanolato-bridging-type coordination rather that the more planar methoxo-type bridging. Furthermore, the creatinine bridging molecule is very slightly distorted from the Re(2)N(2)C plane, indicating that the pyrazolo N atom bonded to the Rh(I) atom is not protonated. Charge balance can thus only be attained if one assumes a positional disorder for the methanolato/methoxo H atom. All attempts to locate disordered protons around these O atoms were unsuccessful. Four hydrogen bonds, one N-H⋯O and three C-H⋯O, are observed in the structure. The mol-ecules pack in a head-to-head and tail-to-tail fashion when viewed along the c axis, in alternating columns.
authors.affiliation: Department of Chemistry, University of the Free State, PO Box 339, Bloemfontein, 9301,  South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Schutte
authors.forename: H G
authors.initials: HG
authors.lastname: Visser
authors.forename: A
authors.initials: A
authors.lastname: Roodt