604-88-6Relevant articles and documents
Aktivierung von Kohlendioxid an Uebergangsmetallzentren: Selektive Cooligomerisation mit Hexin(-3) durch das Katalysatorsystem Acetonitril/Trialkylphosphan/Nickel(0) und Struktur eines Nickel(0)-Komplexes mit side-on gebundenem Acetonitril
Walther, Dirk,Schoenberg, Hartmut,Dinjus, Eckard,Sieler, Joachim
, p. 377 - 388 (1987)
CO2 reacts with hexyne(-3) in a catalytic reaction under formation of tetraethyl-2-pyrone, when the catalytic system alkyl3P/acetonitrile/nickel(0) is used.The selectivity of this homogeneous-catalytic reaction can be increased to values of 96percent when phosphanes of high basicity and small cone angle are used.The investigation of the system Ni(COD)2/tricyclohexylphosphane/acetonitrile shows that acetonitrile can act as ligand in complexes of nickel(0).A yellow-brown tetranuclear complex was isolated, the structure of which was determined by X-ray diffraction studies.Acetonitrile acts as bridging ligand and is coordinated alkyne-analogously to one nickel center with its triple bond.The free electron pair of the nitrogen atom is bonded to a second nickel atom.Some reaction steps of this selective catalytic reaction are discussed.This reaction represents the first example of a selective homogeneous-catalytic co-oligomerization between CO2 and an unsaturated substrate which takes place under C-C linkage with a 3d-transition metal.
Bimetallic Mechanism for Alkyne Cyclotrimerization with a Two-Coordinate Fe Precatalyst
Chakarawet, Khetpakorn,Hait, Diptarka,Head-Gordon, Martin,Tilley, T. Don,Witzke, Ryan J.
, p. 7800 - 7807 (2020)
The two-coordinate compound (IPr)Fe[N(SiMe3)DIPP] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; DIPP = 2,6-diisopropylphenyl) catalyzes the cyclotrimerization of alkynes to arenes. Treatment of the Fe complex with 1 equiv of diphenylacetylene results in the formation of a bimetallic bridging alkyne complex, along with dissociation of IPr from Fe. At elevated temperatures, the bridging alkyne complex undergoes oxidative coupling to form a dimetallacyclopentadiene complex, formally by a one-electron oxidation at each metal center. Each complex catalyzes the cyclotrimerization of diphenylacetylene. Kinetic studies exhibit first-order dependence on the bimetallic complexes, providing further support for the presence of these species in the catalytic cycle. DFT calculations support the experimental mechanistic data and suggest that the catalytic cycle is completed by binding of an alkyne to the diene complex, followed by insertion to form a hexatriene species that then undergoes ring closure to form an inverse sandwich complex, [DIPP(Me3Si)N]Fe(η6-arene)Fe[N(SiMe3)DIPP]. The arene product is then displaced by alkyne to close the catalytic cycle.
Martella,Kaska
, p. 4889 (1968)
Ring Expansion to 1-Bromo-1-alumacyclonona-2,4,6,8-tetraene by Insertion of Two Alkyne Molecules into the AlC Bonds
Agou, Tomohiro,Wasano, Tatsuya,Sasamori, Takahiro,Guo, Jing-Dong,Nagase, Shigeru,Tokitoh, Norihiro
, p. 9568 - 9571 (2015)
Treatment of 1-bromo-2,3,4,5-tetraethylalumole (1) with 3-hexyne afforded the corresponding product 1-bromo-1-alumacyclonona-2,4,6,8-tetraene (2), accompanied by the formation of hexaethylbenzene. In the crystalline state, 2 forms a Br-bridged dimer with a pseudo C2-symmetric and twisted AlC8 nine-membered ring. Deuterium-labeling experiments and DFT calculations on the reaction of 1 with 3-hexyne suggested that 1-bromo-1-alumacyclohepta-2,4,6-triene, which is formed by the insertion of one molecule of 1-hexyne into the AlC bond of alumole 1, is the key intermediate for the generation of 2 as well as hexaethylbenzene. Expanding Al's horizons: A stable alumacyclononatetraene 1 was obtained by the reaction of the corresponding alumole with 3-hexyne accompanied by the formation of hexaethylbenzene. Deuterium-labeling experiments and DFT calculations suggested that an alumacycloheptatriene is the key intermediate (see picture).
Graphdiyne:Structure of Fluorescent Quantum Dots
Chen, Chunying,Guo, Jie,Guo, Mengyu,Jin, Weiyue,Li, Yuliang,Liu, Huibiao,Wang, Fuhui
, p. 16712 - 16716 (2020)
Graphdiyne (GDY) as an emerging two-dimensional carbon allotrope exhibits excellent performance in energy chemistry, catalytic chemistry, optoelectronics, electronics, etc. because of the unique structure combining an sp- and sp2-hybrid carbon network. However, the poor solubility of pristine GDY is a major obstacle to its applications in many fields. Proposed here is a facile strategy to control the preparation of GDY quantum dots (GDY-Py QDs), in which pyrene groups are covalently linked to GDY by using a Sonogashira cross-coupling reaction. The as-prepared GDY-Py QDs, with an average diameter of about 3±0.1 nm, show superior dispersibility in many organic solvents and water. The GDY-Py QDs display not only bright fluorescent with a high relative quantum yield (QY) of 42.82 %, but they are also well-behaved as contrast agents in cell imaging. The GDY-Py QDs are bestowed with high stability and non-cytotoxicity, and exhibit long fluorescent times, and have potential for optical imaging and biomedical applications.
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Grosse,Ipatieff
, p. 559 - 566 (1936)
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Franzus et al.
, p. 1514 (1959)
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Generation of Masked TiIIIntermediates from TiIVAmides via β-H Abstraction or Alkyne Deprotonation: An Example of Ti-Catalyzed Nitrene-Coupled Transfer Hydrogenation
Pearce, Adam J.,Cheng, Yukun,Dunscomb, Rachel J.,Tonks, Ian A.
supporting information, p. 3771 - 3774 (2020/11/13)
Simple Ti amide complexes are shown to act as sources for masked TiII intermediates via several pathways, as demonstrated through the investigation of a unique Ti-catalyzed nitrene-coupled transfer hydrogenation of 3-hexyne. This reaction proceeds through reduction of azobenzene by a masked TiII catalyst, wherein both amines and 3-hexyne can serve as the hydrogen source/reductant for Ti by forming putative titanaziridines via β-H abstraction or putative titanacyclopentynes via protonolysis, respectively.
