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

The synthesis and characterization of two dinuclear complexes, namely fac-hexacarbonyl-1κ3 C,2κ3 C-(pyridine-1κN)[μ-2,2'-sulfanediyldi(ethanethiolato)-1κ2 S1 ,S3 :2κ3 S1 ,S2 ,S3 ]dirhenium(I), [Re2 (C4 H8 S3 )(C5 H5 N)(CO)6 ], (1), and tetraethylammonium fac-tris(μ-2-methoxybenzenethiolato-κ2 S:S)bis[tricarbonylrhenium(I)], (C8 H20 N)[Re2 (C7 H7 OS)3 (CO)6 ], (2), together with two mononuclear complexes, namely (2,2'-bithiophene-5-carboxylic acid-κ2 S,S')bromidotricarbonylrhenium(I), (3), and bromidotricarbonyl(methyl benzo[b]thiophene-2-carboxylate-κ2 O,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 ReI metal centres, while the geometry of the second ReI 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.