A silica-tethered version of the oxorhenium(V) dithiolate oxidation catalyst [-S(CH2)(3)S-]Re(O)(Me)(PPh3) was prepared and characterized by solid state C-13 and P-31 NMR spectroscopy. This tethered Complex (SiO2-RTA)Re(O)(Me)(PPh3) (Fig. 2) catalyzes the selective oxidation of methyl(p-tolyl)sulfide (MTS), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-Me2DBT)) to their corresponding sulfoxides and sulfones by tert-butylhydroperoxide (TBHP) and can be recycled at least four times without loss in activity. Although the rate of oxidation catalyzed by the immobilized catalyst is about a factor of three times lower than the homogeneous analog [-S(CH2)(3)S-]Re(O)(Me)(PPh3), the supported catalyst is much more long-lived achieving approximately 3000 turnovers in the oxidation of DBT at 100 degrees C. The immobilized catalyst effectively catalyzes the oxidation of DBT and the hindered 4,6-Me2DBT to their sulfoxides or sulfores in simulated petroleum feedstocks. (c) 2005 Elsevier B.V. All rights reserved.