MOLECULAR BEAM MASS SPECTROMETRIC INVESTIGATION OF AMMONIA BORANE AND AMINOBORANE VAPORS

The vapors above ammonia borane solid at room temperature include the ammonia borane molecule, BNH6, plus aminoborane, BNH4, and diborane, B2H6, from solid-state decomposition. Direct mass spectrometric observation of the effluent of a flow reactor in which these vapors were pyrolyzed at 5 × 10-5 torr gives no evidence for further formation of aminoborane, nor for iminoborane, BNH2. Surprisingly, aminoborane is much more thermally stable than ammonia borane at these low pressures. Pyrolysis data for the hemideuterio compound, BH3ND3, are consistent with an ethylene-like structure, BH2NH2, for aminoborane rather than the asymmetric structure BHNH3. © 1968, American Chemical Society. All rights reserved.