Aliphatic halides, purification

The most generally applicable method of forming the transition- and inner transition-metal 7t-cyclopentadienyl bond involves the reaction of Na[Cp] with the appropriate anhydrous metal halide or complex halide in an ethereal solvent such as THF or glyme under a dry, inert atmosphere. The complexes are usually isolated by evaporation of the solvent and extraction into an aromatic or aliphatic hydrocarbon solvent. Purification is achieved by crystallization or sublimation. 

The most common procedure for preparing bismuth alkoxides is the substitution reaction of bismuth halides with alkali metal alkoxides. The alternative is treatment of bismuth amides with alcohols. Bismuth alkoxides such as trimethoxide, triethoxide and triisopropoxide were first prepared in 80-93% yields by the reaction between BiCl3 and alkali metal alkoxides by Mehrotra et al. in 1966. Bismuth alkoxides are less soluble in organic solvents and the yields after purification by sublimation are generally very low (10-20%) [66IJC537]. Known aliphatic alkoxides include Bi(OEt)3... 

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