Terminal dysprosium and holmium organoimides.

Terminal rare-earth-metal imide complexes Tp t Bu,Me Ln(NC 6 H 3 iPr 2 -2,6)(dmap) of the mid-late rare-earth elements dysprosium and holmium were synthesized via double methane elimination of Lewis acid stabilized dialkyl precursors Tp t Bu,Me LnMe(GaMe 4 ) with primary aniline derivative H 2 NC 6 H 3 iPr 2 -2,6 (H 2 NAr iPr ). Exploiting the weaker Ln-CH 3 ⋯[GaMe 3 ] interaction compared to the aluminium congener, addition of the aniline derivative leads to the mixed methyl/anilido species Tp t Bu,Me LnMe(HNAr iPr ) which readily eliminate methane after being exposed to the Lewis base DMAP ([double bond, length as m-dash] N , N -dimethyl-4-aminopyridine). Under the same conditions, [AlMe 3 ]-stabilized dimethyl rare-earth-metal complexes transform immediately to Lewis acid bridged imides Tp t Bu,Me Ln(μ 2 -NC 6 H 3 Me 2 -2,6)(μ 2 -Me)AlMe 2 (Ln = Dy, Ho). DMAP/THF donor exchange is accomplished by treatment of Tp t Bu,Me Ln(NC 6 H 3 iPr 2 -2,6)(dmap) with 9-BBN in THF while the terminal imides readily insert carbon dioxide to afford carbamate complexes.