Gas-phase reactions of niobium(1+) and tantalum(1+) with alkanes and alkenes. Carbon-hydrogen bond activation and ligand-coupling mechanisms

The Platinum Hydrido-Methyl Complex: A Frozen Reaction Intermediate?

“…The three peaks remaining in spectrum a correspond to complexes of the three most abundant isotopes of Pt + (194, 195, and 196 amu) with methane, CH 4 . After an additional reaction delay of 3 s, a similar triplet shifted by four units to a higher mass is observed, corresponding to ligand exchange of CD 4 for CH 4 . The same result was obtained, regardless of the specific Pt + Ar m cluster which was used to produce the methane complex.…”

“…As can be seen in Table 2, there is again a fairly strong isotopic effect, with the exchange of perdeuteriomethane for methane, reaction 5 proceeding about a factor of 3 faster than the reverse process, reaction 4. From the rate constant data of Table 2, one can extract the value of the equilibrium constant K ) k (5) /k (4) , and applying the Arrhenius equation compute the difference in the Gibbs free enthalpy:…”

Reactions of Nbn+ (n = 1−15) with Propene and 1-Butene: Product Distribution as a Function of Cluster Size

“…Ligand coupling may be more facile in the reactions with 1-butene than with propene due to the Diels-Alder type mechanism, which has been discussed for the reactions of Nb + . [20][21][22] Ligand coupling mechanisms are also expected in some of the further reaction steps following the fast reactions. The fast reactions stop when all of the reactive sites on the metal clusters have been bonded to the ligands.…”

Concepts of metal-mediated methane functionalization. An intersection of experiment and theory

“…Not surprisingly, methane activation by bare ("naked") transition-metal cations M + has been at the focus of a number of fundamental gas-phase ion studies [7,8]. While several electronically excited ions were reported to dehydrogenate methane (Reaction 1) and to form metal-carbene complexes M(CH 2 ) + [9,10], thermalized ground-state monoatomic 3d-and 4d-transition-metal cations do not react with methane [7,[11][12][13][14][15]. …”