Abstract
New mono- and binuclear complexes of the Mo(η
3-C
3H
5)(CO)
2 fragment, containing bipyridyl ligands (2,2′-bpy, 4,4′-Me
2-2,2′-bpy) as chelates, and mono- (4-CNpy, 4-Mepy, NCMe, Br) or bidentate nitrogen ligands (4,4′-bpy, bipyridylethylene, pyrazine) as terminal or bridging ligands, respectively, were prepared. The binuclear complex [{Mo(η
3-C
3H
5)(CO)
2(2,2′-bpy)}
2(μ-4,4′-bpy)][PF
6]
2 (
2) was shown by X-ray diffraction to assemble in the crystal forming large channels with a rectangular section. A longer bridge, such as bipyridylethylene, led to a different structure (
3). 4-CNpy behaved as monodentate ligand (
4), coordinating through the pyridine nitrogen as a terminal ligand. NMR spectroscopy studies showed that the complexes exhibited a fluxional behavior in solution, the
endo and
exo forms of the more symmetrical equatorial isomers being usually present and interconverting in solution. The solid state structures of the complexes revealed a preference for the more symmetrical equatorial isomer, with the two chelate ligands in
trans positions in the binuclear species. The rings tended to become parallel in the organized crystal.
Several mono- and binuclear bipyridyl complexes of the Mo(η
3-C
3H
5)(CO)
2 fragment were prepared and most of them structurally characterized. One of the two isomers shown here for 4,4′-Me
2-2,2′-bpy and NCMe or Br ligands is observed in the crystal structures. An arrangement with open channels is found for the binuclear derivative of 2,2′-bpy with a 4,4′-bpy bridge.