Surface-mediated synthesis of H4M4(CO)12 (M = ruthenium, osmium) on hydroxylated silica

Surface-Mediated Organometallic Synthesis: High-Yield Preparations of Neutral and Anionic Osmium Carbonyl Clusters by Controlled Reduction of Silica-Supported [Os(CO)3Cl2]2and OsCl3in the Presence of Na2CO3or K2CO3

“…Synthesis of [H 4 Os 4 (CO) 12 ]. The cluster [H 4 Os 4 (CO) 12 ] may be synthesized in good yields by reaction of silica-supported [Os 3 (CO) 12 ] with H 2 (1 atm) at 100−150 °C . Here we report improved silica-mediated syntheses using a more convenient starting material such as α-[Os(CO) 3 Cl 2 ] 2 or OsCl 3 .…”

“…The purity of [Os 3 (CO) 12 ] was controlled by thin-layer chromatography, mass spectroscopy, and infrared spectroscopy . The polynuclear hydrides obtained as impurities were identified by their infrared (in CH 2 Cl 2 ) and 1 H NMR (in CDCl 3 ) spectra. ,− Further extraction of the remaining silica powder with acetonitrile afforded traces of Na 2 [Os 10 C(CO) 24 ], characterized by its infrared spectrum in CH 3 CN …”

“…The field of preparative organometallic chemistry mediated by surfaces is becoming a new area of synthetic chemistry for specific classes of compounds, such as metal carbonyl complexes, whereby the surface of a solid such as an inorganic oxide plays the role of the solvent in conventional syntheses. − As a general trend, strongly basic surfaces such as magnesium oxide favor the formation of anionic metal carbonyl complexes 1,5-6 while neutral complexes are generated on the surface of rather neutral supports such as silica. , However, recently, we found that the anion [H 3 Os 4 (CO) 12 ] - is formed in high yields by reductive carbonylation of OsCl 3 or α-[Os(CO) 3 Cl 2 ] 2 supported on silica in the presence of K 2 CO 3 . It follows that addition of a specific base, such as K 2 CO 3 , may change the properties of the surface, thus allowing the synthesis of anionic metal carbonyl clusters even on silica.…”

Surface-Mediated Organometallic Synthesis: The Activating Role of Silica for a High-Yield Route to [H4Os4(CO)12] and [HOs3(CO)10Y] (Y = OH, OR, Cl, Br, I, O2CR, SCN) Clusters from [Os3(CO)12]

“…A few years ago, some of us reported the easy and high-yield synthesis of [H 4 Os 4 (CO) 12 ] by hydrogenation under 1 atm of H 2 of silica-supported [Os 3 (CO) 12 ] was later explained by us by the formation of silica-anchored [HOs 3 (CO) 10 (OSi⋮)] as reactive intermediate.…”

Volcano relationships in metal cluster catalysis: An infrared spectroscopic monitor of site character

“…The catalytically active cluster was a complex entity. During thermal activation, not only was a small proportion of the carbonyl ligands lost, evolved as gaseous CO, but a further small proportion underwent reaction generating carbon dioxide and leaving ligand-C associated with the catalyst (Boudouard reaction) [3,6,9,[12][13][14].…”