ABSTRACT
New convenient procedures for the preparation of ammonia monochloroborane (NH(3)BH(2)Cl) and cyclotriborazane [(BH(2)NH(2))(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 (NH(2)BHCl)(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 H(δ+)···H(δ-) interactions in the range of 2.00-2.34 Å.
ABSTRACT
DADB synthesis: The diammoniate of diborane (DADB) was synthesized in a new metathesis reaction between the diammoniate of monochloroborane and potassium borohydride in liquid ammonia. (1)H and (11)Bâ NMR spectra of DADB are reported. The stability in THF was examined by variable-temperature (11)Bâ NMR spectroscopy.
ABSTRACT
A simple and efficient way to synthesize unsolvated sodium octahydrotriborate has been developed. This method avoids the use of dangerous starting materials and significantly simplifies the reaction setup, thus enabling convenient large-scale synthesis. The structure of the unsolvated compound has been determined through powder X-ray diffraction.
ABSTRACT
The asymmetric unit of the title salt, 2NH(4)(+).B(10)H(10)(2-).1.5H(2)O or (NH(4))(2)B(10)H(10).1.5H(2)O, (I), contains two B(10)H(10)(2-) anions, four NH(4)(+) cations and three water molecules. (I) was converted to the anhydrous compound (NH(4))(2)B(10)H(10), (II), by heating to 343 K and its X-ray powder pattern was obtained. The extended structure of (I) shows two types of hydrogen-bonding interactions (N-H...O and O-H...O) and two types of dihydrogen-bonding interactions (N-H...H-B and O-H...H-B). The N-H...H-B dihydrogen bonding forms a two-dimensional sheet structure, and hydrogen bonding (N-H...O and O-H...O) and O-H...H-B dihydrogen bonding link the respective sheets to form a three-dimensional polymeric network structure. Compound (II) has been shown to form a polymer with the accompanying loss of H(2) at a faster rate than (NH(4))(2)B(12)H(12) and we believe that this is due to the stronger dihydrogen-bonding interactions shown in the hydrate (I).
