Surface-Mediated Organometallic Synthesis:  High-Yield and Selective Syntheses of Neutral and Anionic Ruthenium Carbonyl Clusters by Controlled Reduction of Silica-Supported RuCl₃in the Presence of Na₂CO₃or K₂CO₃

Abstract

Ru 3 (CO) 10 Cl 2 ], [Ru 3 (CO) 12 ], [H 4 Ru 4 (CO) 12 ], [H 3 Ru 4 (CO) 12 ] -, [HRu 6 (CO) 18 ] -, and [Ru 6 C(CO) 16 ] 2have been synthesized in good or high yields by one-step or two-step (with the surface species [Ru(CO) 3 Cl 2 (HOSit)] as intermediate) one-pot controlled reduction of RuCl 3 supported on silica in the presence of alkali carbonates. The selectivity of the reaction is controlled by the (i) nature and quantity of the alkali carbonate (Na 2 CO 3 or K 2 CO 3 ), (ii) manner by which the alkali carbonate is deposited on the silica surface, (iii) gas-phase composition (CO, CO + H 2 , or CO + H 2 O), (iv) temperature, and (v) reaction time. The unusual selectivity can be explained by the initial formation of [Ru(CO) x (OH) 2 ] n (x ) 2, 3) which, under CO, aggregates first to [Ru 3 (CO) 12 ], key intermediate for the synthesis in situ of various ruthenium carbonyl clusters on the silica surface.

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

“…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 .…”

“…Yields reported for silica-supported Ru 3 (CO) 12 , H 4 Ru 4 (CO) 12 , and [Ru 6 C(CO) 16 ] 2À made from RuCl 3 ranged from 39 to 90%. 53 An advantage of the surface-mediated synthesis is that many reactive mononuclear organometallic precursors (and metal salts) can be used, affording flexibility in the reactivities of the precursors and the ligands, including those that may be retained by the metal. However, this methodology is limited because the procedures do not apply to all supports and because the various support properties (e.g., availability of reactive OH groups, basicity, reducibility, etc.)…”

New insight into a convenient base-promoted synthesis of Ru3(CO)12

“…3 The reaction was rationalized in terms of a reductive elimination of HCl from an elusive hydrido complex produced via de-carboxylation of the initial hydroxy-carbonyl adduct. 2 Independently, interesting reports by Roberto and coworkers, 4 directly inspired by surface-mediated reactions, 5 indicated that a related reduction, albeit conducted on very small quantities of salt and requiring longer reaction times, could be obtained in ethylene glycol in the presence of alkali carbonates.…”

Degradation of toxic halogenated organic compounds by iron-containing mono-, bi- and tri-metallic particles in water

“…They used poly(ethylene glycol) (PEG) as a cross-linker to immobilize Fe/Ni nanoparticles in nylon 6,6 and polyvinylidene fluoride (PVDF). The use of PEG, water soluble, is beneficial to surface modification for metal ion adsorption and reduction; in fact the easy reduction of metal salts in ethylene glycol [60,61], which mimic that occurring on the silica surface [62][63][64][65][66][67], was previously reported. A rapid hydrodechlorination of TCE with ethane as the main end product was observed by the Fe/Ni nanoparticles immobilized in PEG/PVDF or PEG/nylon 6,6.…”