Based on the above data, we propose that the increased activity of POM-PtCl and POM-PtI compared to the non-covalently linked references is due to enhanced electrostatic attraction between the cationic PS and the anionic POMcatalyst. This could enable aggregation and charge-transfer in solution. To test this hypothesis, we performed a combined experimental and theoretical study which explores the interactions between PS and POM-PtX. Due to the higher reactivity, the study used POM-PtI as model.