Tetra-μ(3)-hydroxido-tetra-kis-[tricarbonyl-rhenium(I)] pyridine tetra-solvate

Crystal structure of fac-hexacarbonylbisμ2-(3-carboxy-3′-carboxylato-2,2′-bipyridine)-κ3N,N′:O-dirhenium(I) tetrahydrate, C30H22N4O18Re2

C30H22N4O18Re2, monoclinic, P21/c (no. 14), a = 10.167(7) Å, b = 17.57(1) Å, c = 19.95(1) Å, β = 98.75(1)°, V = 3522(9) Å3, Z = 4, Rgt(F) = 0.0275, wRref(F2) = 0.0633, T = 100(2) K.

Distorted octahedral environments in tricarbonylrhenium(I) complexes of 5-[2-(2,4,6-trimethylphenyl)diazen-1-yl]quinolin-8-olate and 5,7-bis[2-(2-methylphenyl)diazen-1-yl]quinolin-8-olate

The Re(I) centres of two Re(I)-tricarbonyl complexes, viz. tricarbonyl(pyridine-κN){5-[2-(2,4,6-trimethylphenyl)diazen-1-yl]quinolin-8-olato-κ(2)N(1),O}rhenium(I), [Re(C23H21N4O)(CO)3], (I), and {5,7-bis[2-(2-methylphenyl)diazen-1-yl]quinolin-8-olato-κ(2)N(1),O}tricarbonyl(pyridine-κN)rhenium(I), [Re(C28H23N6O)(CO)3], (II), are facially surrounded by three carbonyl ligands, a pyridine ligand and either a 5-[2-(2,4,6-trimethylphenyl)diazen-1-yl]quinolin-8-olate [in (I)] or a 5,7-bis[2-(2-methylphenyl)diazen-1-yl]quinolin-8-olate [in (II)] ligand, in a slightly distorted octahedral environment. The crystal structure of (I) is stabilized by two intermolecular C-H···O interactions and that of (II) is stabilized by three intermolecular C-H···O hydrogen-bonding interactions.

(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)

In the title compound, [Re₂(CH₃O)₂(CO)₆(C₄H₆N₃O)], 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 octa­hedral geometry around each Re^I atom. The bridging methanolato and methoxo ligands are bent out of the Re₂O₂ 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 Re₂N₂C 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 mol­ecules pack in a head-to-head and tail-to-tail fashion when viewed along the c axis, in alternating columns.