Beryllium Halide Complexes Incorporating Neutral or Anionic Ligands: Potential Precursors for Beryllium Chemistry

Reactions of the beryllium dihalide complexes BeX2 (OEt2) 2 (X=Br or I) with N, N, N', N'-tetramethylethylenediamine (TMEDA), a series of diazabutadienes, or bis (diphenylphosphino) methylene (DPPM) have yielded the chelated complexes, BeX2 (TMEDA), BeX2 (RN=CH) 2 (R=tBu, mesityl (Mes), 2, 6-diethylphenyl (Dep) or 2, 6-diisopropylphenyl (Dip) ), and the non-chelated system, BeI2 (κ1 -P-DPPM) 2. Reactions of lithium or potassium salts of a variety of β-diketiminates have given both three-coordinate complexes, HC (RCNAr) 2 BeX (R=H or Me; Ar=Mes, Dep or Dip; X=Br or I) ; and four-coordinate systems, HC (MeCNPh) 2 BeBr (OEt2) and HC (MeCNDip) (MeCNC2 H4 NMe2 BeI. Alkali metal salts of ketiminate, guanidinate, boryl/phosphinosilyl amide, or terphenyl ligands, lead to dimeric BeI{μ-[ (OCMe) (DipNCMe) CH}2 ], and monomeric iPr2 NC (NMes) 2 BeI (OEt2), κ2 -N, P- (HCNDip) 2 B (PPh2 SiMe2) NBeI (OEt2) and C6 H3 Ph2 -2, 6BeBr (OEt2), respectively. Compound HC (MeCNPh) 2 BeBr (OEt2) undergoes a Schlenk redistribution reaction in solution, affording the homoleptic complex, HC (MeCNPh) 2 2 Be. The majority of the prepared complexes have been characterized by X-ray crystallography and multi-nuclear NMR spectroscopy. The structures and stability of the complexes are discussed, as is their potential for use as precursors in poorly developed low oxidation state beryllium chemistry.