183602-14-4Relevant academic research and scientific papers
Phenyl nickel complexes with a chelating P,N ligand. Structures of Ph3P=CHC(=NPh)Ph and [NiPh{Ph2PCH-??C(- ??NPh)Ph}-{Ph3P=CHC(=NPh)Ph-N}]
Braunstein, Pierre,Pietsch, Joerg,Chauvin, Yves,Mercier, Sophie,Saussine, Lucien,DeCian, Andre,Fischer, Jean
, p. 3571 - 3574 (1996)
The complexes [NiPh{Ph2PCH-??C(- ??NPh)Ph}{Ph3P=CHC(=NPh)Ph-N}] and [NiPh{Ph2PCH-??C(- ??NPh)Ph}-(PR3)] (PR3 = PMe3, PMe2Ph or PMePh2) were prepared starting from [Ni(cod)2] (cod = cycloocta-1,5-diene) and the phosphorus ylide Ph3P=CHC(=NPh)Ph I in the presence of a tertiary phosphine. Surprisingly, only the first complex was isolated when PPh3 and P(C6H11)3 were used, whereas the other phosphines led to the corresponding PR3 complexes together with variable amounts of the first depending on their steric demand. The known synthesis of I has been optimized to yields close to 90%. Experiments carried out to study the potential of the nickel compounds as catalysts for ethylene oligomerization showed the stoichiometric formation of styrene and minor amounts of low-molecular-weight linear α-olefins. The molecular structures of I and the first complex have been determined by X-ray diffraction. In the nickel complex the coordination around the metal is distorted square planar, with P(1)-Ni-C(1) and N(1)-Ni-N(2) angles of 90.30(8) and 97.18(8)°, respectively.
