Supported metal oxides are important catalysts for selective oxidation processes, such as alkene epoxidation with H 2 O 2 . The reactivity of these catalysts is dependent on both identity and oxide structure. The dependence of the latter on synthesis method can confound attempts at comparative studies across the periodic table. Here, SiO 2 -supported metal oxide catalysts of Ti(IV), Zr(IV), Hf(IV), V(V), Nb(V) and Ta(V) (all of Groups IV and V) were synthesized by grafting a series of related calixarene coordination complexes at surface densities less than ~0.25 nm -2 . Select catalysts were investigated by solid state NMR, UV-visible, and Xray absorption near edge spectroscopies. As-synthesized and calcined materials were examined for the epoxidation of cyclohexene and styrene (1.0 M) with H 2 O 2 (0.10 M) at 45°C and 65°C.Nb catalysts emerge as high-performing materials, with calcined Nb-SiO 2 proceeding at a cyclohexene turnover frequency of 2.4 min -1 (>2x faster than Ti-SiO 2 ) and with ~85% selectivity towards direct (non-radical) epoxidation pathways. As-synthesized Zr, Hf and Ta catalysts have improved direct pathway selectivities compared to their calcined versions, particularly evident for Ta-SiO 2 . Finally, when the materials are synthesized from these precursors, but not simple metal chlorides, the direct pathway reaction rate correlates with Pauling electronegativities of the metals, demonstrating clear periodic trends in intrinsic Lewis acid catalytic behavior.