An unprecedented bis(carbyne) cluster rearrangement involving simultaneous coupling and decoupling of carbyne fragments: a new homogeneous model for carbon-carbon bond forming and bond breaking on surfaces

Allison, Neil T.; Fritch, John R.; Vollhardt, K. Peter C.; Walborsky, E. C.

doi:10.1021/ja00343a060

Cited by 49 publications

(9 citation statements)

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“…Such a consecutive carbyne migration is unprecedented, and would only be achieved by using the flexibility of the cluster skeleton showing reversible cleavage of an MM bond. Although CC bond formation across a trimetallic plane of a bis(μ 3 ‐alkylidyne) complex has often been observed to yield a (⊥)‐alkyne complex,2a–c such a rearrangement involving the migration of multiple carbon fragments has been quite limited; to the best of our knowledge, there has been only one example, in which migration of a C 2 fragment was shown by using a double‐deck Co 3 system 12. However, there was simultaneous degradation of the cluster skeleton due to high temperature, and mechanical insights in this rearrangement were not clearly shown.…”

Section: Methodsmentioning

confidence: 99%

Pnicogen Bonds: A New Molecular Linker?

Zahn

Frank

Hey-Hawkins

et al. 2011

Chemistry A European J

408

302

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C3 wechselt die Seite: Die Thermolyse eines Trirutheniumkomplexes mit einem μ3‐Pentylidin‐ und einem μ3‐Pentin‐Liganden zu beiden Seiten der von den Metallatomen gebildeten Ebene führt ausschließlich zu einem μ3‐Ethylidin‐μ3‐octin‐Komplex. Bei dieser Reaktion wandert ein C3‐Fragment von einer Seite der Ru3‐Ebene auf die andere, was in einer Umverteilung von zwei C5‐ in ein C2‐ und ein C8‐Molekül resultiert.

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Section: Methodsmentioning

confidence: 99%

Pnicogen Bonds: A New Molecular Linker?

Zahn

Frank

Hey-Hawkins

et al. 2011

Chemistry A European J

408

302

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“…)-alkyne complex, [2a-c] such a rearrangement involving the migration of multiple carbon fragments has been quite limited; to the best of our knowledge, there has been only one example, in which migration of a C 2 fragment was shown by using a double-deck Co 3 system. [12] However, there was simultaneous degradation of the cluster skeleton due to high temperature, and mechanical insights in this rearrangement were not clearly shown.…”

Section: Methodsmentioning

confidence: 99%

Metathesis Reaction of Hydrocarbyl Ligands across the Triruthenium Plane

Tahara¹,

Kajigaya²,

Moriya³

et al. 2010

Angew Chem Int Ed

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Carbon-chain recombination, similar to that observed during the cracking of alkanes and in the Shell higher olefin process, is one of the most important reactions in the chemical industry. There has been a continuous demand for a process that can yield hydrocarbons of desired chain length. Recently, a method for converting lower alkanes into higher alkanes, which is referred to as alkane metathesis, has been reported. [1] Alkane metathesis has considerable scientific and industrial importance because it can convert gaseous hydrocarbons into liquid fuels. Such interconversion involves three catalytic reactions: activation of the alkane CÀH bond, olefin metathesis, and hydrogenation of the formed olefins. However, because of the cross-metathesis of the alkenes during the recombination process, the product will have a molecular weight distribution to some extent.Coupling reactions between two hydrocarbyl ligands placed on both faces of a trimetallic plane have often been seen in organometallic chemistry, [2] as has CÀC bond scission on a cluster.[3] These reactions have attracted considerable attention and are considered to be characteristic of cluster compounds. We have studied C À C bond formation on a triruthenium cluster by directing our attention to the roles of an MÀM bond.[4] Recently, we reported the synthesis of 2 using the coupling reaction of m 3 -benzyne and m 3 -vinylidene ligands separated by the Ru 3 plane of 1 (Scheme 1).[4c] In this reaction, the formation of the ruthenacyclopentadiene skeleton was accompanied by the rupture of a Ru À Ru bond. We also reported the scission of a CÀC bond in a ruthenacyclopentadiene skeleton in which a Ru 3 triangle was reconstructed.[4a] Such flexibility in a cluster skeleton would enable a novel recombination of hydrocarbons. Herein, we report an unprecedented selective interconversion of two C 5 fragments into C 8 and C 2 fragments on a triruthenium cluster.The thermolysis of 4, which was obtained by the sequential treatment of 3 with 1-pentene and 1-pentyne, [5] resulted in the quantitative formation of an equilibrated mixture of 5 a and 5 b (Scheme 2). At ambient temperature, the motion of the hydrido ligand was so rapid that the signals of 5 a and 5 b coalesced. For simplification, we denote this equilibrated mixture as 5.[6] The structures of 4 and 5 were determined by X-ray diffraction studies (Figure 1 and Figure 2, respectively).[7] These results clearly indicate that the m 3 -pentylidyne and m 3 -pentyne ligands in 4 were respectively transformed into the m 3 -ethylidyne and m 3 -octyne ligands in 5.This rearrangement required the migration of the C 3 fragment across the Ru 3 plane. In order to elucidate the mechanism, we monitored the reaction by means of NMR spectroscopy. Upon heating at 80 8C, formation of the m 3 -butylidyne-m 3 -hexyne complex 6 was observed (Path a in Scheme 3). For the formation of 6, a carbyne group must Scheme 1. CÀC bond formation in a trimetallic cluster accompanied by MÀM bond breaking. Cp* = pentamethylcyclopentadienyl. Sche...

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“…Another interesting approach to synthesize oligo-ynes involves “masked alkyne equivalent” (MAE), in which a masking group is used to protect the alkyne from undesired coupling and degradation. − In 1994, one of us reported the masking and unmasking strategy of tetracobalt complexes of tetraynes with the dicobalt tetracarbonyldiphenylphosphinomethane (Co 2 (CO) 4 dppm) . Several other reports are also available for synthesizing oligo-ynes employing Co(0)-based masking agents; however, most of them suffer from challenging demasking step. − Recently, it has been demonstrated that TIPS end-capped oligo-ynes (e.g., 38 ) (Scheme ) could be achieved in good yields from its corresponding MAE via swift removal of the Co 2 (CO) 4 dppm mask . The method started from the synthesis of dicobalt-masked building block 33 from TIPS,TMS-protected triyne 32 .…”

Section: Synthesismentioning

confidence: 99%

Rise of Conjugated Poly-ynes and Poly(Metalla-ynes): From Design Through Synthesis to Structure–Property Relationships and Applications

et al. 2018

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Conjugated poly-ynes and poly(metalla-ynes) constitute an important class of new materials with potential application in various domains of science. The key factors responsible for the diverse usage of these materials is their intriguing and tunable chemical and photophysical properties. This review highlights fascinating advances made in the field of conjugated organic poly-ynes and poly(metalla-ynes) incorporating group 4-11 metals. This includes several important aspects of conjugated poly-ynes viz. synthetic protocols, bonding, electronic structure, nature of luminescence, structure-property relationships, diverse applications, and concluding remarks. Furthermore, we delineated the future directions and challenges in this particular area of research.

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An unprecedented bis(carbyne) cluster rearrangement involving simultaneous coupling and decoupling of carbyne fragments: a new homogeneous model for carbon-carbon bond forming and bond breaking on surfaces

Cited by 49 publications

References 0 publications

Pnicogen Bonds: A New Molecular Linker?

Pnicogen Bonds: A New Molecular Linker?

Metathesis Reaction of Hydrocarbyl Ligands across the Triruthenium Plane

Rise of Conjugated Poly-ynes and Poly(Metalla-ynes): From Design Through Synthesis to Structure–Property Relationships and Applications

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