Octakis(tetracarbonylcobaltio)octasilsesquioxane:  Synthesis, Structure, and Reactivity

Rattay, Michael; Fenske, Dieter; Jutzi, Peter

doi:10.1021/om980128d

Cited by 21 publications

(11 citation statements)

References 8 publications

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“…234 Eight-fold functionalization of octasilsesquioxanes with Co 2 (CO) 8 to give [(OC) 4 CoSiO 1.5 ] 8 (3-175) has been reported in 87% yield. 235 Two reaction pathways have been reported for Fe(η 5 -C 5 H 4 ) 2 SiMeH and Co 2 (CO) 8 (eq 48). In the absence of base, the Co 2 unit is retained, but when base is added, a Co(CO) 4 unit becomes incorporated into the product (3-169).…”

Section: Carbonyl(s) or Carbonyl Unitsmentioning

confidence: 99%

Reactions of Hydrosilanes with Transition Metal Complexes and Characterization of the Products

2011

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Section: Carbonyl(s) or Carbonyl Unitsmentioning

confidence: 99%

Reactions of Hydrosilanes with Transition Metal Complexes and Characterization of the Products

2011

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“…139 Reaction of 75a with four equivalents of Co 2 (CO) 8 yields the remarkable Scheme 20 75f, which was crystallographically characterised and found to be an effective homogeneous catalyst for the hydroformylation of hex-1-ene in the presence of PPh 3 with good chemoselectivity. 140 Further complexes of metals can be formed using species with related structures, such as the reaction of (C 6 H 11 7 Si 7 O 9 (OSiMe 3 )(OH) 2 with AlCl 3 which yields [HNEt 3 ][(cy 7 Si 7 O 9 {OSiMe 3 }O 2 ) 2 Al] 76, suggested to be a model for aluminosilicate minerals. 141 A number of titanium and zirconium complexes of silasesquioxanebased ligands have been prepared and the titanium complexes are active catalysts for epoxidations.…”

Section: Scheme 19mentioning

confidence: 99%

5 Carbon, silicon, germanium, tin and lead

Parr

2000

Annu. Rep. Prog. Chem., Sect. A

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A number of review articles relevant to this chapter have appeared. The area of carbon-rich ligands has been the subject of two timely publications, a special issue of the Journal of Organometallic Chemistry 1 on carbon-rich organometallic complexes and a complementary review on cumulenylidenes. 2 The catalytic applications of metal vinylidenes 3 and the occurrence of planar carbon in organometallic complexes of group 4 and 5 elements 4 have also been reviewed. For silicon, reviews have been in the area of the formation of monolayers 5 and the chemical processing of silicon wafers. 6 A review discussing the role of p-block elements, largely tin, in determining the structure of heterometallic complexes has been published. 7 Despite the discovery of fullerenes, the newest allotrope of carbon, much interest remains in one of the older examples, diamond. The reaction of carbon tetrachloride with four equivalents of sodium metal at 973 K in the presence of a Co/Ni catalyst yields C dia . The product, identi¢ed by Raman spectroscopy, is formed as a powder in a low (ca. 2%) yield, but nevertheless this is amongst the lowest energy routes to industrial diamonds yet known. 8 The same product can be prepared using conditions designed to mimic those found on Uranus and Neptune in which methane is heated to (2^3) Â 10 3 K at pressures of 10^50 gigapascals, whereupon the methane breaks down to form diamond and polymeric hydrocarbons. 9 A convincing argument has been presented for the formation of such a dense solid from a light gaseous phase contributing to the internal heat, magnetic ¢eld and luminosity of a celestial body, and hence the possible signi¢cance of this process in planet formation. A report of the synthesis and identi¢cation of C 6 CH 2 as :C( C C) 2 C CH 2 by removal of the charge from the C 6 CH 2 À. radical anion during neutralisationreionisation mass spectroscopy has been published and related to the cumulenes found in circumstellar dust. 10 Cumulene complexes of transition metals continue to attract much attention. Although synthetic protocols are well established, some new approaches have appeared outlined in Scheme 1. 11,12 The last compound shown is a very rare example of a linear ten atom chain C 8 Rh 2 . Cumulenes with extremely long carbon chains have also appeared, such as 3 which shows in the solid state a distinct twisting of the C 12 chain away from linear, 13 and 4 and 5 (Scheme 2). The crystal structure of 5 shows C^C bond lengths of 1.210^1.233 Ð for triple bonds

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“…21−33 A suitable choice of these groups will allow functionalization, as reported, so that the POSS can behave as a ligand. [34][35][36][37][38]20 Many examples of applications of these species are known, ranging from catalysis 39−51 to analytical chemistry 52−55 and special materials. 56−60 Epoxides are well known as very important intermediates in the industry of fine chemicals and pharmaceuticals that can be formed by oxidation of the corresponding olefin in the presence of various oxygen sources.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Other forms of silica, namely, polyhedral oligomeric silsesquioxane (POSS), − have also been shown to coordinate metallic fragments and generate multiple site catalysts . These species are based on the (RSiO 1.5 ) 8 oligomer, which organizes as a cube held by Si–O–Si bonds and carrying R groups at the vertices. − A suitable choice of these groups will allow functionalization, as reported, so that the POSS can behave as a ligand. − , Many examples of applications of these species are known, ranging from catalysis − to analytical chemistry − and special materials. − …”

Section: Introductionmentioning

confidence: 99%

Catalytic Activity of Molybdenum(II) Complexes in Homogeneous and Heterogeneous Conditions

2015

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The new complexes [MoBr(η3-C3H5)(CO)2(L)2] (C1) and [MX2(CO)3(L)2] (M = Mo(II), X = I (C2); M = Mo(II), X = Br (C3); M = W(II), X = I (C4); M = W(II), X = Br (C5)) were synthesized by reaction of 2-amino-1,3,4-thiadiazole (L) with [MoBr(η3-C3H5)(CO)2(NCCH3)2] (1), [MoI2(CO)3(CH3CN)2](M = Mo (2); M = W (4)), or [MoBr2(CO)3(CH3CN)2](M = Mo (3); M = W (5)) in 2:1 ratio. The five complexes were immobilized in MCM-41, yielding the materials MCM-Cn (n = 1–5), and C1 was also immobilized in silica gel (Silica-C1) and in a polyhedral oligomeric silsesquioxane (Cube-C1). Complexes and materials were fully characterized by spectroscopic techniques and elemental analysis. DFT calculations showed that several C1 isomers should coexist. The as synthesized and supported complexes were tested as catalysts on the oxidation of geraniol, cis-hex-3-en-1-ol, trans-hex-3-en-1-ol, (S)-limonene, and 1-octene. The conversions and TOF significantly depend on the complex and the nature of the substrate. The general conclusions are (i) complex C1 has the highest activity; (ii) tungsten complexes C4 and C5 are more active than the molybdenum analogues; (iii) the immobilization of the catalysts improves the performance; and (iv) silica gel and the polyhedral oligomeric silsesquioxane supports modify the selectivity, leading to products different from the one obtained with MCM for specific substrates.

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Octakis(tetracarbonylcobaltio)octasilsesquioxane: Synthesis, Structure, and Reactivity

Cited by 21 publications

References 8 publications

Reactions of Hydrosilanes with Transition Metal Complexes and Characterization of the Products

Reactions of Hydrosilanes with Transition Metal Complexes and Characterization of the Products

5 Carbon, silicon, germanium, tin and lead

Catalytic Activity of Molybdenum(II) Complexes in Homogeneous and Heterogeneous Conditions

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