14230-18-3Relevant articles and documents
Reactions of dicobalt octacarbonyl with dinucleating and mononucleating bis(imino)pyridine ligands
Hollingsworth, Ryan L.,Beattie, Jeffrey W.,Grass, Amanda,Martin, Philip D.,Groysman, Stanislav,Lord, Richard L.
, p. 15353 - 15363 (2018)
This work focuses on the application of dicobalt octacarbonyl (Co2(CO)8) as a metal precursor in the chemistry of formally low-valent cobalt with redox-active bis(imino)pyridine [NNN] ligands. The reactions of both mononucleating mes
Reactions of alkynes with [RuCl(cyclopentadienyl)] complexes: The important first steps
Dutta, Barnali,Curchod, Basile F. E.,Campomanes, Pablo,Solari, Euro,Scopelliti, Rosario,Rothlisberger, Ursula,Severin, Kay
, p. 8400 - 8409 (2010)
Cyclopentadienyl-ruthenium half-sandwich complexes with η2-bound alkyne ligands have been suggested as catalytic intermediates in the early stages of Ru-catalyzed reactions with alkynes. We show that electronically unsaturated complexes of the formula [RuCl(Cp)(η2-RC=CR')] can be stabilized and crystallized by using the sterically demanding cyclopentadienyl ligand Cp (Cp = η5-l-methoxy-2,4tert-butyl-3-neopentyl-cyclopentadienyl). Furthermore we demonstrate that [RuCl2(Cp)]2 is an active and regioselective catalyst for the [2+2+2] cyclotrimerization of alkynes. The first elementary steps of the reaction of mono(η2- alkyne) complexes containing {RuCl(Cp*)} (Cp* = η5- C5Me5) and (RuCl(Cp)} fragments with alkynes were investigated by DFT calculations at the M06/6-31G* level in combination with a continuum solvent model. Theoretical results are able to rationalize and complement the experimental findings. The presence of the sterically demanding Cp ligand increases the activation energy required for the formation of the corresponding di(η2alkyne) complexes, enhancing the initial regioselectivity, but avoiding the evolution of the system towards the expected cyclotrimerization product when bulky substituents are present. Theoretical results also show that the electronic structure and stability of a metallacyclic intermediate is strongly dependent on the nature of the substituents present in the alkyne.
A simple PdCl2/O2/DMF catalytic system for highly regioselective cyclotrimerization of olefins with electron-withdrawing groups
Jiang, Huan-Feng,Shen, Yan-Xia,Wang, Zhao-Yang
, p. 7542 - 7545 (2007)
A highly regioselective cyclotrimerization of olefins with electron-withdrawing groups in a PdCl2/O2/DMF catalytic system is disclosed, and a possible mechanism has also been proposed, which reveals the PdCl2-catalyzed cyclotrimerization of olefins with electron-withdrawing groups goes through a quite different pathway from that of alkynes.
Cyclotrimerization of alkynes catalyzed by a self-supported cyclic tri-nuclear nickel(0) complex with α-diimine ligands
Shen, Lingyi,Zhao, Yanxia,Luo, Qiong,Li, Qian-Shu,Liu, Bin,Redshaw, Carl,Wu, Biao,Yang, Xiao-Juan
supporting information, p. 4643 - 4649 (2019/04/05)
A cyclic tri-nuclear α-diimine nickel(0) complex [{Ni(μ-LMe-2,4)}3] (2) was synthesized from a “pre-organized”, trimerized trigonal LNiBr2-type precursor [Ni3(μ2-Br)3(μ3-Br)2(LMe-2,4)3]·Br (1; LMe-2,4 = [(2,4-Me2C6H3)NC(Me)]2). In complex 2, the α-diimine ligands not only exhibit the normal N,N′-chelating mode, but they also act as bridges between the Ni atoms through an unusual π-coordination of a C═N bond to Ni. Complex 2 is able to catalyze the cyclotrimerization of alkynes to form substituted benzenes in good yield and regio-selectivity for the 1,3,5-isomers, which is found to vary with the nature of the alkyne employed. This complex represents a convenient self-supported nickel(0) catalyst with no need for additional ligands and reducing agent.
Cyclotrimerization of phenylacetylene catalyzed by a cobalt half-sandwich complex embedded in an engineered variant of transmembrane protein FhuA
Thiel,Sauer,Mertens,Polen,Chen,Schwaneberg,Okuda
supporting information, p. 5452 - 5456 (2018/08/12)
An (η5-cyclopentadienyl)cobalt(i) complex was covalently incorporated into an engineered variant of the transmembrane protein ferric hydroxamate uptake protein component: A, FhuA ΔCVFtev, using a thiol-ene reaction. A CD spectrum shows the structural integrity of the biohybrid catalyst. MALDI-TOF of the segment containing the anchoring site for the cobalt complex Cys545 confirmed successful conjugation. This biohybrid catalyst catalyzed the cyclotrimerization of phenylacetylene to give a mixture of regioisomeric 1,2,4- and 1,3,5-triphenylbenzene in aqueous medium.
