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The widely debated reaction mechanism for the conversion of methanol to hydrocarbons over acidic zeolite H-ZSM-5 has been investigated using isotopic labeling. The mechanistic findings for H-ZSM-5 are clearly different from those previously described at a detailed level for H-beta and H-SAPO-34 catalysts. On the basis of the current set of data, we can(More)
Experimental evidence of protonation of an aromatic ring by a zeolite is hereby presented for the first time. The changes in vibrational properties and electronic transitions of the highest polymethylbenzene homologue, that is, hexamethylbenzene, were investigated after introducing the compound directly into a H-beta zeolite. Protonation of the aromatic(More)
To investigate the possible existence of a complex between the benzenium ion and ethene, computations employing B3LYP and MP2 were carried out. The two methodologies gave conflicting answers; B3LYP confirmed the existence, but according to MP2, the structure found by B3LYP transforms into an ethylbenzenium ion. Computations utilizing the CCSD and QCISD(More)
Recent experimental work on the methanol-to-hydrocarbons (MTH) reaction in zeolite H-Beta suggests that the heptamethylbenzenium (heptaMB+) cation is an important intermediate. We have carried out quantum chemical calculations to investigate intramolecular isomerization reactions and eliminations of small alkenes such as ethene, propene, and isobutene from(More)
A computational study of tert-butylbenzenium ions has been performed. Structures and energies of the various isomers and the transition states for their interconversions have been determined. The existence of a stable π-electron complex (called A1) between a tert-butyl cation and a benzene molecule has been confirmed. Other minimum points on the potential(More)
Proton affinities, stretching from small reference compounds, up to the methylbenzenes and naphthalene and anthracene, have been calculated with high accuracy computational methods, viz. W1BD, G4, G3B3, CBS-QB3, and M06-2X. Computed and the currently accepted reference proton affinities are generally in excellent accord, but there are deviations. The(More)
1. The mode-delivery-effect upon the binding of Sn(IV)-etiopurpurin dichloride (SnET2) in human plasma has been studied by ultracentrifugation, combined with absorption and fluorescence spectroscopy. SnET2 was delivered to plasma either in Cremophore EL (CRM) or in dimethyl sulfoxide (DMSO). To facilitate interpretation, optical, conductivity and(More)
A theoretical investigation of the isopropylbenzenium ion system has been carried out with structures determined with B3LYP. Energies are calculated with the high accuracy composite methods, G3 (G3B3) and CBS (CBS-QB3). The main goal has been to resolve the following issue: Are there any stable ion π-electron complexes of the type C(6)H(6)/C(3)H(7)(+) or(More)