63413-04-7Relevant academic research and scientific papers
Phosphine Substitution in (η5-Cyclopentadienyl)bis(triphenylphosphine)cobalt(I): Evidence for a Dissociative Mechanism
Janowicz, Andrew H.,Bryndza, Henry E.,Bergman, Robert G.
, p. 1516 - 1518 (1981)
The substitution of trimethylphosphine for triphenylphosphine in (η5-cyclopentadienyl)bis(triphenylphosphine)cobalt(I) (1) to form (η5-cyclopentadienyl)(trimethylphosphine)(triphenylphosphine)cobalt(I) was studied at -60 deg C by NMR spectrometry.Kinetic measurements show the process to be first order in 1 and zero order in PMe3; added PPh3 strongly inhibits the reaction rate.This information indicates the reaction proceeds by rapid reversible phosphine dissociation through the unsaturated CpCo(PPh3) intermediate.The rate for generation of that intermediate, k1, is 1.15*10-3 s-1 while the ratio of rate constant k2 (for conversion of intermediate to products) to k-1 (return to starting materials) is 4 at -60 deg C.Possible structures for CpCo(L) are discussed in light of recent indications that the linear structure has a triplet ground state.
