Preparation and characterization of [Re(bpy)(CO)(3)L][SbF6] (L=phosphine, phosphite)

A series of rhenium complexes [fac-Re(bpy)(CO)(3)L][SbF6] (bpy = 2,2'-bipyridine, L = P(Bu-n)(3), PEt3, PPh3, P(OMe)Ph-2, P(O'Pr)(3), P(OEt)(3), P(OMe)(3), P(OPh)(3)) has been prepared and characterized by the IR, UV-vis, H-1 NMR, P-31 NMR, X-ray photoelectron spectroscopy and electrochemical techniques. Variations in the electronic properties, i.e. CO stretching, metal-to-ligand charge transfer transition, and P-31 NMR chemical shifts were interpreted on the basis of the electron-acceptor strength of L. However, the redox potential corresponding to [Re(bpy)(CO)(3)L](+)/[Re(bpy(-))(CO)(3)L] showed 'V-character type' changes after the increase in the electron-acceptor strength of L. Variation of the P(2p) binding energy of the phosphorus atom indicated that the electronic structure of the coordinated phosphorus atom was strongly influenced by the electronic properties of the directly attached substituents.