Nuclearity effects in supported, single-site Fe(II) hydrogenation pre-catalysts

Dimeric and monomeric supported single-site Fe(ii) pre-catalysts on SiO2 have been prepared via organometallic grafting and characterized with advanced spectroscopic techniques. Manipulation of the surface hydroxyl concentration on the support influences monomer/dimer formation. While both pre-catalysts are highly active in liquid-phase hydrogenation, the dimeric pre-catalyst is approximate to 3x faster than the monomer. Preliminary XAS experiments on the H-2-activated samples suggest the active species are isolated Fe(ii) sites.