New Syntheses and Structural Characterization of NH3BH2Cl and (BH2NH2)3 and Thermal Decomposition Behavior of NH3BH2Cl

New convenient procedures for the preparation of ammonia monochloroborane (NH3BH2Cl) and cyclotriborazane [(BH2NH2)3] are described. Crystal structures have been determined by single-crystal X-ray diffraction. Strong H···Cl···H bifurcated hydrogen bonding and weak N–H···H dihydrogen bonding are observed in the crystal structure of ammonia monochloroborane. When heated at 50 °C or under vacuum, ammonia monochloroborane decomposes to (NH2BHCl)x, which was characterized by NMR, elemental analysis, and powder X-ray diffraction. Redetermination of the crystal structure of cyclotriborazane at low temperature by single-crystal X-ray diffraction analysis provides accurate hydrogen positions. Similar to ammonia borane, cyclotriborazane shows extensive dihydrogen bonding of N–H···H and B–H···H bonds with Hδ+···Hδ− interactions in the range of 2.00–2.34 Å.