Synthesis of New Silicon−Cobalt Clusters

Bourg, Stéphane; Boury, Bruno; Carré, Françis; Corriu, Robert J. P.

doi:10.1021/om970685k

Cited by 10 publications

(7 citation statements)

References 38 publications

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“…Shifts for 13 were found at +214.8 and +191.1 ppm and at +213.4 ppm for the bis(dimethylsilylene) compound 14 . These values are in accordance with data found by Corriu et al, whose shifts were in the range between +178 and +210 ppm. 14b,c For dimethylsilylene units bridging to different dimetallic systems very similar resonances have been observed. , …”

Section: Resultssupporting

confidence: 92%

“…One unit is a conventional dicobalt hexacarbonyl acetylene complex, but the other one can be interpreted as a dicobalt octacarbonyl in which the two bridging carbonyl groups have been replaced by dialkylsilylene groups. Structures of similar compounds have been studied previously by Corriu. 14b,c The Co−Co bond length in this unit is elongated to 2.67 Å. The Si−Co distances are in the range between 2.27 and 2.30 Å.…”

Section: Resultsmentioning

confidence: 58%

“…The structural motif of silylenes as bridging ligands for dicobalt complexes is not new. Similar complexes have been obtained by reaction of dicobalt octacarbonyl with hydro- and disilanes. , The reaction mechanism for the transformation of 12b to 13 is not quite clear yet, but it should be noted that the cleavage of silyl acetylene bonds in the coordination sphere of cobalt is not without precedence . The fact that the transformation involves methyl migration from a trimethylsilyl group to the central silicon atom seems to imply the involvement of a cobalt silyl−silylene complex as a reactive intermediate in a similar manner, as described in more detail below.…”

Section: Resultsmentioning

confidence: 64%

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Cobalt-Assisted Silicon−Silicon Bond Activation

2006

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A number of oligosilylalkynes were converted to the respective dicobalt hexacarbonyl complexes. These compounds were found to be surprisingly reactive, indicating Si-Si bond activation in the coordination sphere of the cobalt atoms. The presence of more than one silicon-silicon bond restricted clean conversions, and therefore the pentamethyldisilanylphenylacetylene complex was prepared, which engaged in defined reactions. The rearrangement of an oligosilylalkyne dicobalt hexacarbonyl complex to a dicobalt hexacarbonyl bis(dialkylsilylene) complex was observed. The reaction of tris(trimethylsilyl)silane with dicobalt octacarbonyl yielded the product of formal replacement of two carbonyl ligands with dimethylsilylene groups.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 64%

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Cobalt-Assisted Silicon−Silicon Bond Activation

2006

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“…Compounds with two secondary silyl groups, H 2 SiPh(CH 2 ) 2 SiPhH 2 and H 2 SiMe(C 6 H 4 )SiMeH 2 , react with Co 2 (CO) 8 to form the butterfly-shaped dinuclear complexes [{Co(CO) 3 } 2 {μ-(SiR−X−SiR)}] ( 11 , X = (CH 2 ) 2 , R = Ph; 12 , X = C 6 H 4 , R = Me) (Scheme ) . The molecules have two distorted-octahedral Co atoms bridged with a metal−metal bond and two silylene groups.…”

Section: Disilylated and Digermylated Metallacyclesmentioning

confidence: 99%

Sila- and Germametallacycles of Late Transition Metals

Tanabe

Osakada

2010

Organometallics

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This article reviews recent advances in late-transition-metal complexes with chelating Si and Ge ligands. Compounds with two Si-H bonds, such as bis(silyl)alkanes, bis(silyl)arenes, and tetramethyldisiloxanes, react with Re, Rh, Ir, Pd, and Pt complexes to form disilametallacycles with five-or six-membered chelate rings. Four-and five-membered disilacycloalkanes and disilanyldiylcarboranes undergo Si-Si bond cleavage promoted by Pd(0) and Pt(0) complexes to produce the corresponding disilametallacycles. High reactivity of the Si-Si bond toward oxidative addition facilitates the above ring enlargement, even for compounds with stable five-membered rings. Platinum complexes with a η 2 -silene ligand react with small molecules having electronegative atoms, such as O 2 and NH 3 , to produce metallacycles formed via addition of the electronegative atom to the Si-Si bond. The above disilametallacycles undergo insertion of alkynes and carbonyl compounds into the M-Si bonds of the disilametallacycles. The persilyl metallacycle [ À Pt(SiPh 2 SiPh 2 SiPh 2 À SiPh 2 )(PPh 3 ) 2 ] is obtained by the double oxidative addition of tetrakis-(diphenylsilane) with two Si-H groups and via a metathesis reaction of its dilithio derivative with [PtCl 2 (PPh 3 ) 2 ]. Reactions of H 2 GeAr 2 with Pd(II) and Pt(II) complexes having diphenylgermyl ligands yield the tetragerampalladacyclopentane and its Pt analogue. Trigermaplatinacyclobutane reacts with Ph 2 GeH 2 to produce the tetragermaplatinacyclopentane via formal insertion of GePh 2 into a Pt-Ge bond. C versus Si or Ge MetallacyclesThe chemistry of metallacycles 1 has been a major area of organometallic chemistry because of their role as key intermediates in the metathesis 2 and oligomerization 3 of alkenes catalyzed by transition-metal complexes. Five-and six-membered metallacycles are common, and they are stabilized kinetically in many cases. Their M-C bonds undergo various reactions such as insertion of small molecules, reductive elimination of cycloalkanes, and β-hydrogen elimination, but the reactions occur more slowly than for the usual alkyl complexes due to ring strain of the intermediates or the products. Metallacyclobutanes of Mo, W, and Ru with a four-membered-ring structure are known as the actual intermediates of olefin metathesis catalyzed by the transition-metal complexes. 4 Silyl and germyl complexes of late transition metals exhibit different reactivity from the alkyl metal complexes. For example, they prefer R-hydrogen elimination rather than β-hydrogen elimination, which is common as a decomposition pathway of the alkyl complexes. Chemical properties of the metallacycles, having Si or Ge as the coordinating atoms, are expected to be unique, being cyclic versions of the silyl and germyl complexes. Many research groups have investigated the preparation, structures, and chemical properties of such sila-or germametallacycles. Pd and Pt, in particular, are employed as the major elements among late transition metals, probably because the σ-bonds between Si or Ge and thes...

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“…The central Si 2 Co 2 core of the binuclear clusters 50-52 [97,98] has a butterfly geometry. Their structures differ from each other by the wing tip bridge between two silicon atoms.…”

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confidence: 99%

MOLECULAR STRUCTURE OF ORGANOSILICON COMPOUNDS WITH Si-Fe, Si-Co AND Si-Ni BONDS

Lukevics¹,

Pudova²

2000

Main Group Metal Chemistry

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The results of the structural investigations of the group 8 metal derivatives containing the direct Si-Fe, Si-Co, Si-Ni bonds are summarized in the present review. IntroductionRecently we have published a comprehensive survey of data on the molecular structure of organosilicon compounds with Si-Si [1], Si-Ge, Si-Sn, Si-Pb, Si-Ti, Si-Zr, and Si-Hf bonds [2], as a part of the structural investigations related to the silyl substituted metal derivatives. Herein, we present a review concerning the molecular structure of iron, cobalt and nickel derivatives bearing silyl substituents at the metal atoms. Compounds with transition metal-silicon bonds have been the focus of a considerable interest and there has been remarkable progress over the last few years in the preparation of complexes containing silyl and silylene ligands. This is largely motivated by the possibility to stabilize complexes otherwise unstable, the occurrence of unusual structures, novel reactivity patterns and the construction of clusters having direct metal-metal bonds. These complexes are characterized by a very rich chemistry and have important applications in a number of catalytic processes.

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Synthesis of New Silicon−Cobalt Clusters

Cited by 10 publications

References 38 publications

Cobalt-Assisted Silicon−Silicon Bond Activation

Cobalt-Assisted Silicon−Silicon Bond Activation

Sila- and Germametallacycles of Late Transition Metals

MOLECULAR STRUCTURE OF ORGANOSILICON COMPOUNDS WITH Si-Fe, Si-Co AND Si-Ni BONDS

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