Synthesis and Multiple Subsequent Reactivity of Anionic cyclo-E Ligand Complexes (E=P, As).

A synthetic pathway for the synthesis of novel anionic sandwich complexes with a cyclo-E (E=P, As) ligand as an end deck was developed giving [Cp'''Co(η -E )] (Cp'''=1,2,4-tri-tert-butylcyclopentadienyl, E=P ([5]), As ([6])) in good yields suitable for further reactivity studies. In the reaction with the chlorophosphanes R PCl (R=Ph, Cy, Bu), neutral complexes with a disubstituted cyclo-E P (E=P, As) ligand in [Cp'''Co(η -E PR )] (E=P (7 a-c), As (9 a-c)) were obtained. These compounds can be partially or completely converted into complexes with a cyclo-E (E=P, As) ligand with an exocyclic {PR } unit in [Cp'''Co(η :η -E PR )] (E=P (8 a-c), As (10 a-c)). Additionally, the insertion of the chlorosilylene [LSiCl] (L=( BuN) CPh) into the cyclo-E ligand of [5] and [6] was achieved and the novel heteroatomic complexes [Cp'''Co(η -E SiL)] (E=P (11), As (12)) could be isolated. The reaction pathway was elucidated by DFT calculations.