One Step Closer to Structural Models for HDS Catalysts: Thienyl-Oxo Complexes of Re(V)

Article abstract of DOI:10.1021/ic00125a022

The present investigation focuses on thiophene derivatives of oxometal centers with low d-electron counts. Treatment of a THF slurry of ReOCl3(PPh3)2 with thienyllithium reagents afforded Li(THF)nReO(thienyl)4 wherethienyl is 2-C4H3S, 2-MeC4H2, 2-C8H5S (benzothienyl), and 2-C12H7S (dibenzothienyl). In contrast to the previously reported low-valent derivatives these species are reactive toward protic and oxidizing reagents. Electrochemical studies demonstrate that these Re(V) complexes undergo oxidation at mild potentials. Crystallographic analyses of Li(THF)3ReO(C4H3S)4 and Li(THF)4ReO(C8H5S)4 indicate a square pyramidal Re center with the four thienyl ligands tilted in a pinwheel arrangement. Studies on Re(2-C4H3S)(CO)5 reveal that it is stable toward hydrolysis.