Methane Activation by [OsC₃]⁺: Implications for Catalyst Design

Abstract

Gas-phase reactions of [OsC 3 ] + with methane at ambient temperature have been studied by using quadrupole-ion trap mass spectrometry combined with quantum chemical calculations. The comparison of [OsC 3 ] + with the product clusters revealed significant changes in cluster reactivity. In particular, with different ligands, the cluster may produce multiple products or, alternatively, just a single product. Theoretical calculations reveal the influence of electronic features such as molecular polarity index, charge and spin distribution, and HOMO−LUMO gap on the reactivity of the Os complexes. Fundamentally, it is the polarity of the clusters that leads to the cluster reactivity in the methane activation. Furthermore, reducing the local polarity of the catalyst active site may be one means of reducing the number of byproducts in the reaction.

Consecutive Reduction of Five Carbon Dioxide Molecules by Gas-Phase Niobium Carbide Cluster Anions Nb3C4–: Unusual Mechanism for Enhanced Reactivity by the Carbon Ligands

“…The study of clusters in isolated conditions, combined with quantum chemistry, is an innovative tool for uncovering the mechanisms of complex catalytic transformation processes that occur over active sites in condensed phases. , Some new insights into the ligand effect on the activation of CO 2 by transition metals have been provided through gas-phase cluster studies. , The ligands, such as B, S, H, N, CH 2 , and NH units, have been developed to study the activation and conversion of CO 2 by gas-phase clusters. − In contrast, there are few reports on the ligand effect of C atoms on the activation of CO 2 . , Most studies on metal carbide clusters investigate reactions with N 2 − and CH 4 . − Quite recently, He and coworkers reported that the noble metal-containing carbide cluster RhTaC 2 – can consecutively reduce four CO 2 molecules to CO, emphasizing the central role of multiple metal bonds in CO 2 activation …”