Electrostatic nature of catalytic effects resulting from Si>Al substitutions in ZMS-5 zeolite

Catalytic activity changes resulting from Si>Al substitution modelled by corresponding ab initio cluster calculations have been compared with analogous perturbational values obtained from an atomic multipole expansion. Preliminary results indicate the dominant electrostatic nature of the long-range catalytic effects in cluster models of substituted zeolites. This opens the possibility to dissect catalytic effects in modified zeolites into additive increments derived directly from an atomic multipole representation of the molecular charge redistribution. Such an approach may be potentially useful in the rational design of optimal catalysts of extensive size.