High Pressure Equilibria of Dimethylamine Borane, Dihydridobis(dimethylamine)boron(III) Tetrahydridoborate(III), and Hydrogen

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• 作者：Robert G. Potter ; Maddury Somayazulu ; George Cody ; Russell J. Hemley
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：April 10, 2014
• 年：2014
• 卷：118
• 期：14
• 页码：7280-7287
• 全文大小：403K
• 年卷期：v.118,no.14(April 10, 2014)
• ISSN：1932-7455

文摘

The interaction of hydrogen and deuterium with dimethylamine borane (Me₂NHBH₃) was studied at pressures from 0 to 10 GPa. Me₂NHBH₃ is stable to isothermal compression in noble gas pressure media up to 16 GPa. During these compressions a strong positive pressure dependence of the frequencies of BN and BH stretching fundamentals was observed. The opposite trend was observed with NH modes. Me₂NHBH₃ + He mixtures remain phase separated over the entire 0鈥?6 GPa range. During the isothermal compression of Me₂NHBH₃ + H₂ mixtures two separate phases are observed at low pressure which subsequently collapse into one phase above 3 GPa. Prior to the formation of the Me₂NHBH₃/H₂ phase loss of the H₂ vibron was observed concurrently with the growth of broad features in the 3600鈥?000 region. Further compression of the Me₂NHBH₃:H₂ results in the growth of new Raman-active BN, BH, and NH modes not present in noble gas compressions. These modes are assigned to the new high pressure solid: [(Me₂NH)₂BH₂⁺][BH₄^{鈥?/sup>] similar to the so-called diammoniate of diborane often observed in experiments with ammonia and diborane at ambient pressure.}