Abstract
Probing and determining the intermediates formed during catalytic reactions in heterogeneous catalysis are strong challenges. Using (13)C labelling and two dimensional (13)C-(13)C through-bond NMR correlations, we directly reveal the structures of a range of carbenium ion species formed during the conversion of methanol to olefins on acidic H-ZSM-5 zeolite by mapping the carbon-carbon bond connectivities. Additionally, we use (13)C-(27)Al and (29)Si-(13)C through-space NMR experiments to probe the interactions between the confined carbon species (including carbenium ions) and the framework of the zeolite, which quantitatively provide an estimate for the carbon-aluminium and carbon-silicon distances, respectively.