Boron halide chelate compounds and their activity towards the demethylation of trimethylphosphate

Salen(t-Bu)H₂ (N,N′-ethylenebis(3,5-di-tert-butyl(2-hydroxy)benzylidenimine) and its derivatives were used to prepare boron compounds having the formula L(BCl₂)₂ (L = salen(t-Bu) (1), salpen(t-Bu) (2), salben(t-Bu) (3), salpten(t-Bu) (4), salhen(t-Bu) (5)). These are formed from the reaction of the corresponding (L[B(OMe)₂]₂ with BCl₃. In addition to being a new type of boron compound, they are also potential two-point Lewis acids. Indeed, they demonstrate Lewis acidic behavior in the dealkylation of trimethylphosphate. All of the compounds were characterized by mp, elemental analysis, ¹H and ¹¹B NMR, IR, MS, and in the case of 2 by X-ray crystallography.