Facile Formation of FePd Nanoparticles from Single-Source [1]Ferrocenophane Precursors

Mixed-metal FePd alloy nanoparticles (NPs) have been synthesized in moderate yield (ca. 55–60%) and at relatively low temperatures from single-source [1]­ferrocenophane precursors. Thermolysis of [Fe­(η5-C5H4)2­Pd­(PnBu3)2] (7) (1 h, 150 °C) and the new species [Fe­(η5-C5H4)2­Pd­{PnBu2­(CH2)4­PnBu2}] (9) (1 h, 190 °C) afforded crystalline, heterobimetallic FePd alloy NPs with diameters of ca. 4 nm (11) and 3.5 nm (12), respectively, together with mixtures of unidentified, mainly ligand-derived products. Both sets of particles were analyzed by high resolution transmission electron microscopy, which, in addition to providing particle size, determined the spacing between the lattice fringes to be 0.23 nm. Evidence for the formation of alloy nanoparticles, rather than a mixture of those comprising pure metals, was obtained by energy-dispersive X-ray analysis, which confirmed the presence of both Fe and Pd in a single particle. This assertation was further supported by wide-angle X-ray scattering of 11 and 12, which displayed broad reflections at 2θ = 40.58° and 40.09°, respectively, in good agreement with previous studies of FePd NPs. Atomic absorption spectroscopy was employed for bulk analysis of the particles and indicated that that the compositions of 11 and 12 were ca. Fe35Pd65.