Heterolytic cleavage of dihydrogen (HCD) in metal nanoparticle catalysis

Abstract

Supports, ligands and additives can promote heterolytic H2 splitting by a cooperative mechanism with metal nanoparticles.

Heterolytic Dissociation of H2 in Heterogeneous Catalysis

“…On the other hand, extensive efforts have been devoted to diminishing or blocking the metal–metal pairs by creating an oxide or organic overlayer to steer the relative kinetic significance of different reaction pathways and consequently product selectivity (Figure ). − It is worth noting that the heterolytic H 2 dissociation on metal nanoparticles has been summarized in a comprehensive review by Cano et al…”

Design of gold catalysts for activation of H2 and H-donor molecules: transfer hydrogenation and CO2 hydrogenation

“…The resulting H 2 -ion pair can be used, for instance, to selectively hydrogenate the CO moiety. 60 The number of examples of processes comprising heterolytic cleavage of H 2 is growing fast, not only in gold catalysts, as recently reviewed by van Leeuwen et al 61 and Zheng et al 8 The application of the free ligand on a large scale might be limited by the high cost and additional product purification steps. Therefore, a fully heterogeneous catalyst composed of gold embedded in N-doped carbon (Au@N-doped carbon/TiO 2 ) that mimics the ligand on the gold surface was developed for the hydrogenation of alkynes 51 and aldehydes.…”

Air-Stable Ni Catalysts Prepared by Liquid-Phase Reduction Using Hydrosilanes for Reactions with Hydrogen

“…Siloxide (R 3 SiO) ligands are known to form weak interactions between metal and oxygen due to back-bonding of oxygen p orbitals with Si–C σ* orbitals, which polarizes the M–OSi bonds . Based on previous reports in which the heterolytic cleavage of H 2 could be accomplished by neighboring metal oxides or surface organic compounds with basic sites, , the negatively charged oxygen of the organosiloxy group would enable the heterolytic cleavage of H 2 on positively charged nickel ions. Although the organosiloxy group may contribute to the reduction of surface Ni oxides, the heterolytic cleavage of H 2 would not affect the catalytic hydrogenation of unsaturated compounds because the tendency of the functional groups to be easily hydrogenated is similar to that of the reported nickel catalyst. − As mentioned above, Si–H bonds are necessary for the reduction of Ni­(acac) 2 .…”