CH Activation by a Heavy Metal Cation: Production of H2 from the Reaction of Acetylene with C4H4-Os(+) in Gas phase

Abstract

While first-row transition metal cations, notably Fe(+), catalyze the gas-phase conversion of acetylene to benzene, a distinct path is chosen in systems with Os, Ir, and Rh cations. Rather than losing the metal cation M(+) from the benzene–M(+) complex, as is observed for the Fe(+) system, the heavy metal ions activate CH bonds. The landmark system C4H4-Os(+) reacts with acetylene to produce C6H4-Os(+) and dihydrogen. Following our work on isomers of the form C2nH2n-Fe(+), we show by DFT modeling that the CH bonds of the metalla-7-cycle structure, C6H6-Os(+), are activated and define the gas-phase reaction path by which H2 is produced. The landmark structures on the network of reaction paths can be used as a basis for the discussion of reactions in which a single Os atom on an inert surface can assist reactions of hydrocarbons.

Cryogenic Photoelectron Spectroscopic and Theoretical Study of the Electronic and Geometric Structures of Undercoordinated Osmium Chloride Anions OsCln– (n = 3–5)

“…The transition metal osmium (Os), one of the rarest metals found in the Earth’s crust, exhibits exceptional physical properties and is recognized as the densest known metallic element . As a transition metal, Os can form coordination compounds with a variety of ligands, leading to a wide range of applications across numerous fields, including the development of novel catalysts, − materials with specific magnetic properties, , and new medicinal agents in bioinorganic chemistry. − Coordination compounds such as OsCl 6 2– and C 4 H 4 –Os­(+) have demonstrated utility in chemical reduction processes, catalyzing the conversion of H 2 O to H 2 and acetylene to hydrogen as well as facilitating the conversion of carbonyl compounds to alcohols. ,− In all cases, the reactivity of transition metal–ligand compounds is heavily influenced by the electronic configurations of the central transition metal atom, metal–ligand bond properties, and the number of coordinate bonds.…”