Highly Electron‐Rich β‐Diketiminato Systems: Synthesis and Coordination Chemistry of Amino‐Functionalized “<i>N</i>‐nacnac” Ligands

Abstract

Abstract The synthesis of a class of electron‐rich amino‐functionalized β‐diketiminato ( N ‐nacnac) ligands is reported, with two synthetic methodologies having been developed for systems bearing backbone NMe 2 or NEt 2 groups and a range of N ‐bound aryl substituents. In contrast to their (Nacnac)H counterparts, the structures of the protio‐ligands feature the bis(imine) tautomer and a backbone CH 2 group. Direct metalation with lithium, magnesium, or aluminium alkyls allows access to the respective metal complexes through deprotonation of the methylene function; in each case X‐ray structures are consistent with a delocalized imino‐amide ligand description. Transmetalation using lithium N ‐nacnac complexes is then exploited to access p‐ and f‐block metal complexes, which allow for like‐for‐like benchmarking of the N ‐nacnac ligand family against their more familiar Nacnac counterparts. In the case of Sn II , the degree of electronic perturbation effected by introduction of the backbone NR 2 groups appears to be constrained by the inability of the amino group to achieve effective conjugation with the N 2 C 3 heterocycle. More obvious divergence from established structural norms is observed for complexes of the harder Yb II ion, with azaallyl/imino and even azaallyl/NMe 2 coordination modes being demonstrated by X‐ray crystallography.