Lithium tetrahydroborate

Lithium tetrahydridothallate(III), 24 632 Lithium tetrahydroborate, physical properties of, 4 194t Lithium—thionyl chloride cells, 3 466 characteristics, 3 462t speciality for military and medical use, 3 430t... 

Lithium tetradeuteroaluminate, 0069 Lithium tetrahydroaluminate, 0075 Lithium tetrahydroborate, 0145 Lithium tetrahydrogallate, 4407 Magnesium tetrahydroaluminate, 0085 Manganese(II) tetrahydroaluminate, 0086 Potassium hexahydroaluminate(3—), 0077 Potassium tetrahydrozincate, 4516 Potassium trihydomagnesate... 

Synonyms lithium tetrahydroborate hthium boron hydride... 

Zirconium(IV) and hafnium(IV) tetrakis(tetrahydroborates) M(BH4)4 are of interest as extremely volatile, covalent complexes that contain tridentate BH ligands and exhibit rapid intramolecular exchange of bridging and terminal hydrogen atoms. 4,615 These compounds were prepared initially from NaMF5 (M = Zr or Hf) and excess A1(BH4)3 (equation 53),616 but they are obtained more conveniently from the reaction of the anhydrous metal tetrachloride with excess lithium tetrahydroborate (equation 54), either in the solid state617,618 or in the presence of a small amount of diethyl ether.619... 

The chemical reactions of M(BH )4 complexes have received very little attention. Both compounds behave as Lewis adds in reactions with tetraalkylammonium and lithium tetrahydroborates, yielding [(C8Hi7)3NPr][M(BH4)5], [NBu4][M(BH4)5] and LiM(BH4)5.620 Zr(BH4)4 reacts with LiAlH4 in ether to give Zr(AlH4)4, an unstable white solid, which decomposes within several hours at room temperature to a pyrophoric black solid.617... 

Aluminium dichloride hydride diethyl etherate, 0061 Aluminium tetrahydroborate, 0058 Caesium hexahydroaluminate(3—), 0067 Copper tetrahydroaluminate, 0068 Lithium tetrahydroaluminate, 0075 Lithium tetrahydroborate, 0145 Manganese(II) tetrahydrolaluminate, 0086 Potassium hexahydroaluminate, 0077 Sodium tetrahydroaluminate, 0076 ... 

Many variations " have been used in the preparation of borazines and boranes. The first convenient syntheses utilized lithium tetrahydroborate and an amine hydrochloride in ether. An attempt was made to modify these procedures so that the above boron-nitrogen compounds... 

The preparations described below represent a balance among the several rate factors, the availability of starting materials, and the over-all convenience of the procedure. In particular, the use of sodium tetrahydroborate instead of lithium tetrahydroborate eliminates both the handling of a pyrophor and the contamination of the products with ether-soluble lithium salts. 

BH4Li (s) LiBH4 (s) Lithium Tetrahydroborate BH4Li (s) LiBH4 (s)... 

Alkali-metal tetrahydraborate reduction of phosphorus halides is of limited utility . Lithium tetrahydroborate reaction with PClj or PClj in Et20 at — 80°C produces PHj, but yields are low" ... 

Lithium tetrahydroborate can substitute for LiAlH. The LiBH reduction occurs with inversion of configuration at Ge, whereas LiAlH cleavage occurs with retention of configuration. 

Me,SbH yields of 35% are obtained. Lithium tetrahydroborate reduction of PhSbL ... 

Lithium tetrahydroborate-d reduction of chloroarsines yields deuteroarsines, in reactions " more efficient than those using LiAlD. ... 

Tetrahydroborates also reduce halosilanes to the parent silanes. Lithium tetrahydroborate reduces SiCl to SiH in high yield in addition, it is more selective than LiAlH. Lithium tetrahydroborate reacts with alkoxychlorosilanes to reduce Si—Cl bonds but without reduction of Si—O bonds, providing a good route to alkoxysilanes ... 

Hydroborates in the presence of an ester or of methyl iodide have also been used for hydroborations. For example, the system lithium tetrahydroborate-ethyl acetate provides a simple route to dialkylboryl compounds (equation 12). Alkynes provide alkenylboron compounds. 

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