Vinyl/Phenyl Exchange Reaction within Vinyl Nickel Complexes Bearing Chelate [P, S]-Ligands

Three nickel(II) hydrides, [2-Ph2P(4-Me-C6H3)S]NiH(PMe3)2 (1), [2-Ph2P(6-Me3Si-C6H3)S]NiH(PMe3)2 (2), and [2-Ph2P(4-Me3Si -C6H3)S]NiH(PMe3)2 (3), were synthesized via S–H bond activation through the reaction of Ni(PMe3)4 with (2-diphenylphosphanyl)thiophenols. The reactions of nickel(II) hydrides (1–3) with different alkynes were investigated. Although the first step is the insertion of alkyne into the Ni–H bond for each reaction, different final products were isolated. Normal vinyl nickel complex [2-Ph2P(4-Me-C6H3)S]Ni(CPh═CH2)(PMe3) (4) was obtained by the reaction of phenylacetylene with 1. The nickelacyclopropane complexes [2-Ph2P(6-Me3Si-C6H3)S]Ni[Ph(PMe3)C–CH2] (5), [2-Ph2P(4-Me3Si-C6H3)S]Ni[Ph(PMe3)C–CH2] (6), [2-Ph2P(4-Me3-C6H3)S]Ni[Ph(PMe3)C–CHPh] (7), [2-Ph2P(6-Me3Si-C6H3)S]Ni[Ph(PMe3)C–CHPh] (8), [2-Ph2P(4-Me3Si-C6H3)S]Ni[Ph(PMe3)C–CHPh] (9), [2-Ph2P(4-Me-C6H3)S]Ni[Ph(PMe3)C–CHSiMe3] (10) or [2-Ph2P(4-Me-C6H3)S]Ni[Me3Si(PMe3)C–CHPh] (10), [2-Ph2P(6-Me3Si-C6H3)S]Ni[Ph(PMe3)C–CHSiMe3] (11) or [2-...