Reactivity Of (c_5me_5)_3lal_x Complexes: Synthesis Of Atris(pentamethylcyclopentadienyl) Complex With Twornadditional Ligands, (c_5me_5)_3la(nccme_3)_2

摘要

The limits of steric crowding in tris(pentamethylcyclopentadienyl) complexes have been expanded by isolation of the first compound with this ligand set and two additional ligands, (C_5Me_5)_3ML_2. This result was obtained in a study of the effect of added ligands on the reactivity of sterically crowded (C_5Me_5)_3La, 1. Although neither THF nor Ph_3PO formed crystallographically characterizable (C_5Me_5)_3LaL_x complexes with 1, these (C_5Me_5)_3La/L_x mixtures displayed enhanced reactivity compared to 1 with substrates such as C_8H_8 and CO_2. Attempts to use adamantyl azide, AdN_3, to make (C_5Me_5)_3LaL_x complexes led to the first example of azide insertion into a metal cyclopentadienyl linkage to generate (C_5Me_5)_2La[η~2-(N,N')-(C_5Me_5)NN'N"Ad](N_3Ad). Addition of Me_3CCN to 1 produced the first crystallographically characterized (C_5Me_5)_3ML_2 complex, (C_5Me_5)_3La(NCCMe_3)_2.