Heteronuclear Cobalt Clusters by Metal Exchange

Beurich, Harald; Vahrenkamp, Heinrich

doi:10.1002/anie.197808631

Cited by 60 publications

(14 citation statements)

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“…As mentioned previously, two essentially identical X-ray structures of type 3 a have been reported (12,13) and also one of type 3b. Another molecule closely analogous to 13 is the (C5H5)Fe3(C0)8C-OMe cluster 14 reported by Aitchison and Farrugia (21), and shown in Fig.…”

Section: Ar Omesupporting

confidence: 72%

“…The rotational barrier for the interconversion of rotamers 3a and 3b is approximately 8.5-9.5 kcal mol-' depending on the nature of the substituents at the carbynyl capping position and within the cyclopentadienyl ring (14). The clusters 11 and 12 reported by Vahrenkamp (12) and by Stone (13) adopt structural type 3a and, very recently, the latter rotamer, viz. 3b, has been characterized X-ray crystallographically for the particular case of (C,Me,)MoCo2(CO),C-CO,'Pr, 13 (15).…”

Section: M(co) Rotation In F~c O ( C O )~Smentioning

confidence: 97%

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Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co₂Fe(CO)₉S, CpMoCo₂(CO)₈CR, and in Cp₂Mo₂(CO)₄(RC≡CR)

Malisza¹,

Li²,

McGlinchey³

1996

Can. J. Chem.

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Molecular orbital calculations at the extended Huckel level are used to rationalize the baniers to vertex rotation in the tetrahedral metal cluster complexes F~CO,(CO)~S, 2, and (C5H5)MoCo,(CO),CH, 3. It is shown that, in accord with experimental observations on 2, rotation of an Fe(CO), fragment through 60' brings about a weakening of the metal-metal bonding interactions within the FeCo, triangle. In the MoCo, cluster, 3, rotation of the CpMo(CO), fragment about an axis joining the molybdenum to a central point within the tetrahedron gives rise to three minima in which the cyclopentadienyl ring is orientedproximal or distal relative to the capping carbynyl moiety, or in the plane of the three metals. The rotation trajectory of the CpMo(CO), vertices in Cp,Mo,(CO),(HC=CH), 4, has been elucidated by means of a Burgi-Dunitz analysis of the X-ray crystal structures of a series of related clusters in which the CpMo(CO), units exhibit a range of orientations. The calculations suggest that the barriers to vertex rotations in 4 are primarily of steric rather than electronic origin.Key words: metal clusters, vertex rotations, EHMO calculations.

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Section: Ar Omesupporting

confidence: 72%

Section: M(co) Rotation In F~c O ( C O )~Smentioning

confidence: 97%

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co₂Fe(CO)₉S, CpMoCo₂(CO)₈CR, and in Cp₂Mo₂(CO)₄(RC≡CR)

Malisza¹,

Li²,

McGlinchey³

1996

Can. J. Chem.

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“…Such behavior is found for coordination clusters with a chiral framework. [58][59][60][61][62][63][64][65][66][67][68] In the second, the inorganic core can be achiral and the optical activ- A) The calculated chiral structure (C 1 ) of bare Au 55 is more stable than the highly symmetric structure (I h ). Reprinted from ref.…”

Section: Possible Mechanism and Theoretical Studiesmentioning

confidence: 99%

“…[92][93][94] Chiral metal NPs can potentially combine the chirality of their core or surface and of their organic shell to induce enantioselectivity on prochiral substrates, as suggested previously for organometallic clusters with a chiral framework. [58][59][60][61][62][63][64][65][66][67][68] Despite the impressive progress in catalysis, however, only a few NP systems were found to be efficient in asymmetric catalysis till today. [75,86,[95][96][97][98][99][100][101][102][103] The most relevant systems involve Pt and Pd NPs stabilized by cinchonidine, in the hydrogenation of pyruvate derivatives with ee up to 95-98 %.…”

Section: Potential Applicationsmentioning

confidence: 99%

Chiral Gold Nanoparticles

2009

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Monolayer-protected gold nanoparticles have many appealing physical and chemical properties such as quantum size effects, surface plasmon resonance, and catalytic activity. These hybrid organic-inorganic nanomaterials have promising potential applications as building blocks for nanotechnology, as catalysts, and as sensors. Recently, the chirality of these materials has attracted attention, and application to chiral technologies is an interesting perspective. This minireview deals with the preparation of chiral gold nanoparticles and their chiroptical properties. On the basis of the latter, together with predictions from quantum chemical calculations, we discuss different models that were put forward in the past to rationalize the observed optical activity in metal-based electronic transitions. We furthermore critically discuss these models in view of recent results on the structure determination of some gold clusters as well as ligand-exchange experiments examined by circular dichroism spectroscopy. It is also demonstrated that vibrational circular dichroism can be used to determine the structure of a chiral adsorbate and the way it interacts with the metal. Finally, possible applications of these new chiral materials are discussed.

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“…[12][13][14][15] Studies in organometallic chemistry showed that bi nary halides of both main group and transition metals are most reactive in transmetallation reactions. 16 14 ] -(see Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

Replacement of Fe atoms by Ru in a carbidocarbonyl cluster [Fe6C(CO)16]2−. Structures of reaction products

et al. 2005

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The reaction of the carbidocarbonyl cluster [Fe 6 C(CO) 16 ] 2-with ruthenium(IV) hydroxo chloride Ru(OH)Cl 3 was studied. At 90-100 °C, the reaction gave products of replacement of Fe atoms by Ru in the [Fe 6 C(CO) 16 ] 2-cluster along with degradation products. Treatment of the replacement products with FeCl 3 afforded the [Fe 2.96 Ru 3.04 C(CO) 17 ] compound (1), which was characterized by X ray diffraction analysis. The crystals of cluster 1 are composed of two types of octahedral molecules (1a and 1b) in a ratio of 2 : 1. Molecules 1a are in general positions, and molecules 1b are located on twofold axes. In both molecules, the Fe and Ru atoms are disordered over four of six positions.Heterometallic clusters are important members in a series of transition metal compounds and are of particular interest for the stereochemistry and materials science. 1,2 Heterometallic carbidocarbonyl clusters 1-4 occupy a spe cial place among these promising compounds. More than 90 such clusters containing from one to four different metals (Fe, Co, Ni, Cr, W, Rh, Pd, Pt, Cu, and Ru) 1-4 have been synthesized and characterized.We have developed procedures for the synthesis of such clusters with specified geometry for a wide range of metals. The most promising method for the preparation of such clusters is based on the indirect replacement of vertices in a metal polyhedron. This process generally involves the removal of a vertex from the metal core fol lowed by the addition of another metal at this posi tion. 1,5-9 The synthetic potential of this method is far from being exhausted. Hence, we continued studies of transmetallation of [Fe 6 C(CO) 16 ] 2-, extended our inves tigation to a wider range of metallating systems, and gave greater attention to the conditions of this complex reac tion accompanied by oxidative degradation of the starting cluster and products of its transmetallation.In the present study, we investigated the reaction of the carbidocarbonyl cluster [Fe 6 C(CO) 16 ] 2-with ruthenium(IV) hydroxochloride Ru(OH)Cl 3 . We iso lated products of replacement of Fe by Ru in the [Fe 6 C(CO) 16 ] 2-cluster along with the earlier de scribed 10,11 derivatives of oxidative degradation products, the clusters (µ H)Ru 2 Fe 2 PdC(CO) 12 (η 3 C 10 H 15 ) and Fe 3 RuPd 2 C(CO) 12 (η 3 C 10 H 15 ) 2 . Results and DiscussionTo perform successful replacement of one metal with another, a combination of the following two conditions is required: redox interaction of the metal carbonyl anion with metal chloride and simultaneous carbonylation of the resulting zero valent metal. 12-15Studies in organometallic chemistry showed that bi nary halides of both main group and transition metals are most reactive in transmetallation reactions. 16,17 Earlier, we have studied the reactions of the cluster anions [Fe 6 C(CO) 16 ] 2-and [Fe 5 C(CO) 14 ] 2-with a number of transition metal halides. 12,17,18 It was found that these dianions, like other metal carbonyls, can reduce transi tion metal halides.For example, heating of rhodium trichloride with [...

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Heteronuclear Cobalt Clusters by Metal Exchange

Cited by 60 publications

References 10 publications

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co₂Fe(CO)₉S, CpMoCo₂(CO)₈CR, and in Cp₂Mo₂(CO)₄(RC≡CR)

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co₂Fe(CO)₉S, CpMoCo₂(CO)₈CR, and in Cp₂Mo₂(CO)₄(RC≡CR)

Chiral Gold Nanoparticles

Replacement of Fe atoms by Ru in a carbidocarbonyl cluster [Fe6C(CO)16]2−. Structures of reaction products

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Heteronuclear Cobalt Clusters by Metal Exchange

Cited by 60 publications

References 10 publications

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co2Fe(CO)9S, CpMoCo2(CO)8CR, and in Cp2Mo2(CO)4(RC≡CR)

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co2Fe(CO)9S, CpMoCo2(CO)8CR, and in Cp2Mo2(CO)4(RC≡CR)

Chiral Gold Nanoparticles

Replacement of Fe atoms by Ru in a carbidocarbonyl cluster [Fe6C(CO)16]2−. Structures of reaction products

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Product

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Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co₂Fe(CO)₉S, CpMoCo₂(CO)₈CR, and in Cp₂Mo₂(CO)₄(RC≡CR)

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co₂Fe(CO)₉S, CpMoCo₂(CO)₈CR, and in Cp₂Mo₂(CO)₄(RC≡CR)