Synthesis of Re tricarbonyl complexes with various sulfur- and oxygen-donating ligands: crystal structures of two Re dinuclear structures bridged by S atoms.

The synthesis and characterization of two dinuclear complexes, namely fac-hexacarbonyl-1κC,2κC-(pyridine-1κN)[μ-2,2'-sulfanediyldi(ethanethiolato)-1κS,S:2κS,S,S]dirhenium(I), [Re(CHS)(CHN)(CO)], (1), and tetraethylammonium fac-tris(μ-2-methoxybenzenethiolato-κS:S)bis[tricarbonylrhenium(I)], (CHN)[Re(CHOS)(CO)], (2), together with two mononuclear complexes, namely (2,2'-bithiophene-5-carboxylic acid-κS,S')bromidotricarbonylrhenium(I), (3), and bromidotricarbonyl(methyl benzo[b]thiophene-2-carboxylate-κO,S)rhenium(I), (4), are reported. Crystals of (1) and (2) were characterized by X-ray diffraction. The crystal structure of (1) revealed two Re-S-Re bridges. The thioether S atom only bonds to one of the Re metal centres, while the geometry of the second Re metal centre is completed by a pyridine ligand. The structure of (2) is characterized by three S-atom bridges and an Re...Re nonbonding distance of 3.4879 (5) Å, which is shorter than the distance found for (1) [3.7996 (6)/3.7963 (6) Å], but still clearly a nonbonding distance. Complex (1) is stabilized by six intermolecular hydrogen-bond interactions and an O...O interaction, while (2) is stabilized by two intermolecular hydrogen-bond interactions and two O...π interactions.