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Transition metal carbyne complexes are organometallic compounds with triple bond between carbon and the transition metal. This triple bond consists of a sigma bond and two pi bonds.〔Transition Metal Complexes with Terminal Carbyne Ligands Advances in Organometallic Chemistry Vol. 27. Page 52.〕 The HOMO of the carbyne ligand interacts with the LUMO of the metal to create the sigma bond. The two pi bonds are formed when the two HOMO orbitals of the metal back donate to the LUMO of the carbyne. They are also called metal alkylidynes—the carbon is a carbyne ligand. Such compounds are useful in organic synthesis of alkynes and nitriles. They have been the focus on much fundamental research.〔Elschenbroich, C. ”Organometallics” (2006) Wiley-VCH: Weinheim. ISBN 978-3-527-29390-2.〕 ==Synthesis== Transition metal carbyne complexes are most common for the early transition metals, especially Nb, Ta, Mo, W, and Re. They can also have low-valence metals as well as high-valence metals. The first example of a metal carbyne complex was prepared by the Fischer school by treatment of Cr(CO)5(C(OMe)Ph) with boron trichloride: :Cr(CO)5(C(OMe)Ph) + BCl3 → ClCr(CO)4(CPh) + CO + BCl2(OMe) Many high valent carbyne complexes have since been prepared, often by dehydrohalogenation of carbene complexes. Alternatively, amino-substituted carbyne ligands sometime form upon protonation of electron-rich isonitrile complexes. Similarly, O-protonation of μ3-CO ligands in clusters gives hydroxycarbyne complex. Vinyl ligands have been shown to rearrange into carbyne ligands. Addition of electrophile to vinylidene ligands also affords carbyne complexes.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Transition metal carbyne complex」の詳細全文を読む スポンサード リンク
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