Four-coordinate erbium organometallic and coordination complexes: Synthesis and structure

The synthesis and reactivity of several erbium organometallic and coordination complexes supported by a β-diketiminato ancillary ligand are described. The reaction of ErCl3(THF)3.5 with LiL (L = ArNC(Me)CHC(Me)NAr; Ar = 2,6-iPr2-C6H3) afforded the dimeric complex Er(L)Cl(μ-Cl)3Er(L)(THF), 1. Reaction of complex 1 with four equiv of the bulky silylamide LiN(SiMe3)2 generated the unexpected four-coordinate adduct dimer [Er(L)N(SiMe3)2Cl(μ-(LiN(SiMe3)2))]2, 2. Conversely, reaction of 1 with two or four equiv of LiCH2SiMe3 led to the base-free mixed chloro/alkyl species [Er(L)(CH2SiMe3)(μ-Cl)]2, 3, and the four-coordinate dialkyl Er(L)(CH2SiMe3)2, 4, respectively. The protonolysis reactivity of 4 was demonstrated by reaction with [Et3NH]I to generate Er(L)I2, 5. By contrast, reaction of complex 1 with trimethylsilyliodide resulted in the formation of ErI3(THF)3, 6, through a ligand redistribution process. Compounds 1–6 were characterized by single crystal X-ray diffraction, multinuclear NMR spectroscopy, FT-IR spectroscopy, solution magnetic susceptibility measurements and CHN combustion analysis.