Imaging of Nearly Uniform Os₅C Clusters Dispersed on MgO Powder

Abstract

Os 5 C(CO) 14 ] 2was synthesized in 65% yield on the surface of MgO by treatment of adsorbed [Os 3 (CO) 12 ] in CO. High-resolution transmission electron microscopy (HRTEM) indicated that the nanoclusters were nearly monodisperse and in the size range consistent with [Os 5 C(CO) 14 ] 2-. The supported [Os 5 C(CO) 14 ] 2was decarbonylated in helium, giving supported nanoclusters that are well approximated as Os 5 C, as shown by HRTEM and EXAFS data. Decarbonylation in H 2 gave larger clusters of osmium, as shown by HRTEM.

Metal clusters on supports: synthesis, structure, reactivity, and catalytic properties

“…5 and 6, but, significantly, the images of pentaosmium clusters (Fig. 8) 51 and of decaosmium clusters (Fig. 7) 87 demonstrate high degrees of uniformity of the clusters.…”

“…With these methods, researchers have been able to synthesize supported clusters of various nuclearities, including osmium carbonyls (tri-, 22,24,46,47 tetra-, 48,49 penta-, 50,51 and decaosmium) 42,43 prepared from Os 3 (CO) 12 and ruthenium carbonyls 52,53 prepared from Ru 3 (CO) 12 and even from RuCl 3 .…”

Triosmium Clusters on a Support: Determination of Structure by X‐ray Absorption Spectroscopy and High‐Resolution Microscopy

“…[2,[16][17] Determination of the structures of the metal frames in supported metal clusters has benefited from recent advances in transmission electron microscopy (TEM); now, even the smallest metal clusters can be imaged. [16,18,19] The most informative images of metal clusters have been obtained with high-resolution scanning transmission electron microscopy (STEM). [6,[20][21][22][23][24] Recent advances in STEM instruments and image analysis methods [25][26][27] have allowed determination of Abstract: The structures of small, robust metal clusters on a solid support were determined by a combination of spectroscopic and microscopic methods: extended X-ray absorption fine structure (EXAFS) spectroscopy, scanning transmission electron microscopy (STEM), and aberration-corrected STEM.…”

Supported Metal Cluster Catalysts

“…A few supported metal clusters have been imaged by TEM, with sharp images having been obtained for clusters on MgO that were inferred to be predominantly [Os 5 C(CO) 14 ] 2− and Os 5 C formed by its decarbonylation [24]. The image of Fig.…”