115289-34-4Relevant academic research and scientific papers
Insertion of Coordinated Olefins into the Organyl-Metal Bond of CpNi(organyl)(η2-olefin) Complexes
Lehmkuhl, Herbert,Keil, Thomas,Benn, Reinhard,Rufinska, Anna,Krueger, Carl,et al.
, p. 1931 - 1940 (2007/10/02)
The CpNiR(η2-CH2=CH2)complexes 1-13 react with insertion of the coordinated ethylene into the Ni-R bond.In the cases where R = Ph (5) and p-C6H4X , the primary reaction products D can be trapped at -50 deg C to -10 deg C by complexation to ethylene, to give, e.g., CpNi(p-CH2CH2C6H4X)(η2-CH2=CH2), 22 and 23, or to ethylene to give 24.Rearrangement to the (1,2,7-η3-benzyl)NiCp complexes 14-21 occurs in the absence of excess ethylene.The rate of insertion of the complexed ethylene increases (relative to the CpNiPh compound 5) in the presence of donor substituents in the p-Ph position and decreases in the presence of acceptor groups.The complexes Cp*Ni(p-C6H4X)(η2-CH2=CH2) 25-27 are less reactive; they require temperatures ca. 30 deg C higher than their Cp analogues to form the ethylene complexes of their insertion products.The η2-butadiene compounds CpNiR(1-2-η2-CH2=CHCH=CH2) 3-allyl)NiCp compounds 35b-37b and these rearrange at 60 deg C to the thermodynamically more stable syn isomers a.The reactivity of the Cp(organyl)Ni(η2-olefin)complexes with respect to olefin insertion into the organyl-Ni bond decreases in the order: CpNi(p-C6H4X)(butadiene) > CpNi(p-C6H4X)(C2H4) > Cp*Ni(p-C6H4X)(C2H4) > CpNi(alkyl)(C2H4) (alkyl = Me, Et > Pr, Bu).
