Novel High-Yield Method for the Synthesis of [Os₃(CO)₁₀(μ-H)(μ-OSiR₂R‘)] Species and X-ray Characterization of [Os₃(CO)₁₀(μ-H)(μ-OSiPh₂OSiPh₂OH)] and [Os₃(CO)₁₀(μ-H)(μ-OSiPh₂OH)], First Molecular Models of Osmium Surface Species Anchored to Vicinal and Geminal Surface Silanols

Abstract

The easy replacement of the hydroxy ligand in [Os3(CO)10(μ-H)(μ-OH)] by siloxy ligands affords a high-yield procedure to model compounds of the type [Os3(CO)10(μ-H)(μ-OSiR2R‘)] (R = Et, Ph; R‘ = Et, Ph, OH, OSiPh2OH), a springboard to better understand the reactivity of osmium carbonyl species on the silica surface. The new clusters [Os3(CO)10(μ-H)(μ-OSiPh2OH)] and [Os3(CO)10(μ-H)(μ-OSiPh2OSiPh2OH)], characterized by X-ray crystallography, represent the first molecular models of silica-anchored [Os3(CO)10(μ-H)(μ-OSi⋮)] having a ligand that mimics surface geminal and vicinal silanols, respectively.

Synthesis and Characterization of Osmium-Containing Silsesquioxanes: High-Yield Routes to {Os3(CO)10(μ-H)[(μ-O)Si7O10(c-C6H11)7]} and the New Clusters {Os3(CO)10(μ-H)[(μ-O)Si7O9(OH)2(c-C6H11)7]}, {[Os3(CO)10(μ-H)]2(μ-O)2Si7O9(OH)(c-C6H11Lucenti1, Feher2 2006OrganometallicsSelf Cite14180View full textAdd to dashboardCite

“…The average Os−O lengths of 2.08−2.13 Å for the two osmium atoms bridged by μ-oxygen in clusters 5 , 8 , and 9 are in agreement with the Os−O distance of 2.16 Å measured for the alumina-supported cluster [Os 3 (CO) 10 (μ-H)(μ-OAl<)] . The interatomic distances and intrabond angles within the Os 3 clusters are not significantly different from those in other crystallographically characterized Os 3 (CO) 10 -containing clusters, including [Os 3 (CO) 10 (μ-H)(μ-Y)] with Y= OSiEt 3 , OSi 7 O 10 (c-C 6 H 11 ) 7 , OSiPh 2 OH, and OSiPh 2 OSiPh 2 OH 1 ORTEP plot of 5 with thermal ellipsoids plotted at the 50% probability level.…”

“…The goal of our work was to determine whether Os 3 clusters juxtaposed to potentially reactive Si−OH groups could interact via hydrogen bonding or undergo low-energy reactions not seen with simpler silanols. The springboard for this work was the recent development of a high-yield synthesis of [Os 3 (CO) 10 (μ-H)(μ-OH)] ( 3 ), which is known to react cleanly with silanolsincluding silanols with more than one SiOH groupto produce osmium carbonyl clusters with the formula [Os 3 (CO) 10 (μ-H)(μ-OSiR 2 R‘)] (R = Et, Ph; R‘ = Et, Ph, OH, OSiPh 2 OH) . The results from our studies, as well as their implications for the chemistry of silica-supported complexes, are discussed below.…”

Synthesis, Spectroscopic, and X-ray Characterization of Rhenium Carbonyl Complexes with Different Silsesquioxanes, as Models That Mimic the Chemical Behavior and the Topology of the Silica Surface

“…Other models of rhenium carbonyl surface species were synthesized and structurally characterized, such as the species [Re 2 (CO) 8 (μ-H)(μ-OSiR 2 R′)] (R = Et, Ph; R′ = Et, Ph, OH, OSiPh 2 OH), where the OSiR 2 R′ group may mimic the interaction with isolated, geminal, and vicinal surface silanols. By analogy with the known easy anchoring of [Os 3 (CO) 12 ] on the silica surface by oxidative addition to give the silica-anchored [Os 3 (CO) 10 (μ-H)(μ-OSi)] species, as confirmed by surface models, the latter Re complexes could be models of the silica-anchored [Re 2 (CO) 8 (μ-H)(μ-OSi)] species possibly formed by thermal or photochemical oxidative addition of [Re 2 (CO) 10 ] with the silica surface. , …”

“…Although models of silica-anchored carbonyl species of various noble metals (for example Rh, Os, , and Ru) have been thoroughly investigated, much less is known about models involving oxophilic metals such as rhenium, , despite the industrial relevance of catalysts based on rhenium supported on inorganic oxides for reactions such as olefin metathesis, epoxidation, hydrogenation, dehydrogenation, and petroleum refining…”

Synthesis, reactivity and X-ray crystal structure of tris(pentafluorophenyl)silanol (C6F5)3SiOH

“…The investigation on the structure and reactivity of silica-anchored organometallic species has been improved in the last two decades also through the complementary investigation on the synthesis, structure and reactivity of molecular models bearing silanolate ligands which mimic the silanol groups of the silica surface [1][2][3][4][5][6][7]. For instance, some of us reported evidence for the peculiar stabilization of the rhenium pentacarbonyl species [Re(CO) 5 OSi≡] on the silica surface, but the synthesis of its molecular model [Re(CO) 5 OSiR 3 ] was hampered by the fact that nucleophiles, such as Me 3 SiO -, are exceptionally good cis-labilizing ligands that facilitate the instantaneous loss of carbonyl ligands and further nucleophilic attacks to give dimeric units bridged by silanolate groups such as [Re 2 (CO) 6 (-OSiMe 3 ) 3 ] - [8].…”