Preparation, spectra and X-ray structure of an archetypal coordination compound [BCl3(NH3)] and its thermolysis

Abstract

Crystalline [BCl₃(NH₃)]1 is obtained in low yield from [NH₄]Cl and BCl₃ in toluene, with trichloroborazine (BClNH)₃2 as the principal product; detailed NMR spectroscopic data on 1 in CDCl₃ are consistent with the X-ray structure, which shows intermolecular hydrogen bonding with four molecules in the unit cell [(H ⋯ Cl)_av 2.76(3)Å], B–N 1.579(4), (B–Cl)_av 1.837(4) and (N–H)_av 0.86(5)Å, with the boron and nitrogen environments approximately tetrahedral; thermolysis of 1 yields 2 and a TGA experiment shows that at 450 °C boron nitride is the ultimate product.