Tungstosilicic acid readily undergoes salt metathesis with a Mn(1,4,7-trimethyl-1,4,7-triazacyclononane) complex to form a Mn-tungstosilicic salt. This compound, being insoluble in all common solvents, was used as a heterogeneous catalyst in oxidation reactions with H2O2 as an oxidising agent. Its catalytic performance was directly compared to the homogeneous Mn-catalyst counterpart. Despite leaching of manganese into the solution, all evidences suggest, that the reaction is taking place at the solid surface rather than in solution. The catalytic selectivity of both Mn-complexes was comparable, but the activity of the Mn-tungstosilicic salt was lower than the homogeneous counterpart.