The confinement effect on the adsorption and reaction mechanism of unsaturated aliphatic, aromatic and heterocyclic compounds on H-ZSM-5 zeolite has been investigated by the four ONIOM methods (MP2:M06-2X), (MP2:B3LYP), (MP2:HF), and (MP2:UFF). The H-ZSM-5 'nanoreactor' porous intersection, where chemical reactions take place, is represented by a quantum cluster of 34 tetrahedral units. Ethene, benzene, ethylbenzene, and pyridine are chosen to represent reactions of various adsorbates of aliphatic, aromatic and heterocyclic compounds. Among the four combined methods, (MP2:M06-2X) outperforms the others. The results confirm that the method that takes weak interactions, especially the van der Waals interaction, into account is essential for describing the confinement effect from the zeolite framework. The effects of the infinite zeolitic framework on the cluster model are also included by a set of point charges generated by the embedded ONIOM model. The energies for the adsorption of ethene, benzene, ethylbenzene, and pyridine on H-ZSM-5 from an embedded ONIOM(MP2:M06-2X) calculation are predicted to be -14.0, -19.8, -24.7, and -48.4 kcal/mol, respectively, which are very close to available experimental observations. The adsorption energy of pyridine agrees well with the experiment data of -47.6 kcal/mol. We also applied the same computational methodology on the systematic investigation of the H/H exchange reaction of benzene and ethylbenzene with the acidic H-ZSM-5 zeolite. The H/H exchange reaction was found to take place in a single concerted step. The calculated apparent activation energies for benzene and ethylbenzene are 12.6 and 4.9 kcal/mol, which can be compared to the experimental estimates of 11.0 and 6.9 kcal/mol, respectively. The confinement effect of the extended zeolite framework has been clearly demonstrated not only to stabilize the adsorption complexes but also to improve their corresponding activation energies to approach the experimental benchmark.

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and its interactions with propylene were investigated by density-functional (B3LYP/6-31G(d,p)) and ONIOM (B3LYP/6-31G(d,p): UFF) calculations. For comparison, the carbonyl-ene reaction of propylene and formaldehyde was also studied with Cu + alone as a catalyst. It was found that the metal-organic framework leads to an energy barrier of the reaction ∆E act of 24.1 kcal/mol. This compares to values of ∆E act of 34.4 kcal/mol for the uncatalyzed system and 6.4 kcal/mol if the reaction takes place with the Cu + alone. The carbonyl-ene reaction of propylene using HCHO@MOF-11 takes place in a single concerted reaction step. The ∆E act value for MOF-11 is similar to that obtained for the zeolite catalyzed reaction (∆E act ) 25.