Pt+-mediated activation of methane: theory and experiment

Gas-phase activation of methane by ligated transition-metal cations

“…With the increased knowledge gathered in recent years, both experimentally and theoretically, some mechanistic guidelines for the interpretation of the primary, intramolecular KIEs associated with the C-H(D) bond activation of methane can be provided, however. For the platinum species listed in the left side of Table 1, the KIEs are generally quite low, which is consistent with the view that for platinum not the activation step itself, but the release of the products is rate-determining (5,27,79). In contrast, a sizable KIE occurs in the case of the nickel(II) fluoride cation NiF ϩ , which is consistent with the view that this reaction proceeds as a -bond metathesis in which C-H(D) bond cleavage and H(D)-F bond formation contribute to the rate-determining step (40).…”

Potential energy surfaces and mechanisms for activation of ethane by gas-phase Pt+: A density functional study

“…The calculated relative energies for all stationary points are archived and compared. Our calculations indicate that the energies obtained for all stationary points in the doublet state are evidently lower than those in the quartet state, as seen in the systems concerning Pt + -catalyzed activation of methane [38,39,49]. Thus, there is no spin crossing involved in the title reactions, and only the mechanism of doublet state was investigated here.…”

“…The ionization energy of Pt is calculated to be 8.74 eV, being very close to the experimental value of 9.0 eV [37]. The dissociation energy for the Pt + -CH 2 ( 2 A 1 ), which is a very important quantity for a description of this title reaction, is calculated to be 118.0 kcal/ mol, showing good agreement with the experimental value of 114.6 ± 1 kcal/mol [38]. In addition, the calculated dissociation energies for the complexes Pt + -CH( 2 A 1 ), Pt + -CH 3 ( 1 A 1 ), Pt + -H( 1 P + ), and Pt + -C( 2 P + ), which agree fairly well with the experimental values [39], are given in Table 1.…”

Activated Methane on Small Cationic Platinum Clusters

“…[7] In the case of small ionic clusters reacting with CH 4 under single collision conditions, Pt n [C,2H] + complexes were found to be the favored products. [8][9][10] There have been a number of computational studies of the interactions of platinum clusters [11][12][13] and surfaces [5,14,15] with methane, primarily using density functional theory (DFT).…”