The reaction of 2-naphthyl with 1,3-butadiene: a theoretical study

This work is devoted to a theoretical study of the 2-naphthyl + 1,3-butadiene reaction aimed at understanding the hydrogen-loss mechanism in the reactions of n-naphthyl (n=1,2) with 1,3-butadiene. All intermediates and transition states, their vibrational frequencies and zero-point vibrational energies, and the potential energy diagram were calculated at the G3(MP2,CC)//B3LYP/6-311G** theoretical level. The estimate of the reaction rate constant gives the order of 10-13 cm3 molecule-1 s-1 at temperatures below 500 K.

Density-functional calculations of the conversion of methane to methanol on platinum-decorated sheets of graphene oxide

The calculated optimum potential-energy diagram of methane conversion on (a) Pt2/GO, (b) Pt2O/GO, and (c) Pt2O2/GO sheets.

Correlation between bowl-inversion energy and bowl depth in substituted sumanenes

The correlation between the bowl-inversion energy and the bowl depth for sumanenes monosubstituted with an iodo, formyl, or nitro group was investigated experimentally and by theoretical calculations. The bowl-inversion energies of the substituted sumanenes were determined experimentally by two-dimensional NMR exchange spectroscopy measurements. Various density functional theory methods were examined for the calculation of the structure and the bowl-inversion energy of sumanene, and it was found that PBE0, ωB97XD, and M06-2X gave better fits of the experimental value than did B3LYP. The experimental value was well reproduced at these levels of theory. The bowl structures and bowl-inversion energies of monosubstituted sumanenes were therefore calculated at the ωB97XD/6-311+G(d,p) level of theory. In both the experiments and the calculations, the correlation followed the equation ΔE = acos4 θ, where a is a coefficient, ΔE is the bowl-inversion energy, and cos θ is the normalized bowl depth, indicating that the bowl inversion follows a double-well potential energy diagram.

Direct NO decomposition over stepped transition-metal surfaces

We establish the full potential energy diagram for the direct NO decomposition reaction over stepped transition-metal surfaces by combining a database of adsorption energies on stepped metal surfaces with known Brønsted-Evans-Polanyi (BEP) relations for the activation barriers of dissociation of diatomic molecules over stepped transition- and noble-metal surfaces. The potential energy diagram directly points to why Pd and Pt are the best direct NO decomposition catalysts among the 3d, 4d, and 5d metals. We analyze the NO decomposition reaction in terms of a Sabatier-Gibbs-type analysis, and we demonstrate that this type of analysis yields results that to within a surprisingly small margin of error are directly proportional to the measured direct NO decomposition over Ru, Rh, Pt, Pd, Ag, and Au. We suggest that Pd, which is a better catalyst than Pt under the employed reaction conditions, is a better catalyst only because it binds O slightly weaker compared to N than the other metals in the study.