Borane-Tetrahydrofuran

[14044-65-6] C4H11BO (MW 85.94) InChI = 1S/C4H8O.BH3/c1-2-4-5-3-1;/h1-4H2;1H3 InChIKey = RMCYTHFAWCWRFA-UHFFFAOYSA-N (hydroborating and reducing agent) Physical Data: d420 = 0.898 g cm−3 for 1 M solution in THF. Solubility: sol THF; reacts violently with water. Form Supplied in: solution in THF 1 M in BH3, stabilized with 0.005 M sodium borohydride. Analysis of Reagent Purity: 11B NMR: δ −0.7 ppm (JB–H = 103 Hz).5 Active hydride is determined by hydrolysis of an aliquot in a mixture of glycerol and water (1∶1) and measuring the hydrogen evolved according to a standard procedure.6a Boric acid formed by hydrolysis is determined by titration with standard sodium hydroxide in the presence of mannitol. Preparative Methods: Diborane is conveniently generated by the reaction of Sodium Borohydride with Boron Trifluoride in diglyme and absorbed in THF.2 The solution, ca. 2 M in BH3, may contain traces of boron trifluoride, which poses problems only on rare occasions.3 Diborane synthesis has been reviewed.4 Handling, Storage, and Precautions: use in a fume hood; air- and moisture-sensitive, flammable liquid; handle and store under nitrogen or argon. Commercial solutions are stable over prolonged periods when stored at 0 °C under nitrogen. Unstabilized solutions can be kept for several weeks under those conditions. However, in such solutions the BH3 concentration may slowly decrease due to the cleavage of THF by borane.6b