Synthesis of Lanthanide Bromide Complexes from Oxides. The Crystal Structures of [LnBr₂(diglyme)₂][LnBr₄(diglyme)] (Ln = Sm, Eu) and [LnBr₂(HMPA)₄]Br·0.5H₂O (Ln = La, Sm)

The reaction of the lanthanide oxides, bromotrimethylsilane and water in THF resulted in [LnBr 3 (THF) x ]. If digylme (diglyme = diethylen glicol dimethyl ether) was added to these reaction mixtures in the mole ratio n(Ln): n(diglyme) ∼ 1: 2.2 – 3, the ionic complexes [LnBr 2 (diglyme) 2 ][LnBr 4 (diglyme)] (Ln = La ( 1 ), Sm ( 2 ), Eu ( 3 )) were isolated. Crystal structures of the two new complexes, 2 and 3 , which were recrystallized from dichloromethane, were determined. The immediate reaction of the complexes 1 and 2 with HMPA (HMPA = hexamethylphosphoramide) in toluene resulted in [LnBr 2 (HMPA) 4 ]Br·0.5H 2 O (Ln = La( 4 ), Sm ( 5 )).