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

Abstract

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 -2,6}BeBr(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.