First-Principles Calculations of Potassium Amidoborane KNH2BH3: Structure and 39K NMR Spectroscopy

We have studied the structural, electronic, and vibrational properties of potassium amidoborane (KAB, KNH2BH3) using density-functional theory (DFT) calculations. The optimized structural parameters of KAB were found to be in good agreement with the experimental data. The electronic structure calculations suggested the covalent characters of N-H, B-H, and N-B as well as the ionic character of K. Moreover, we computed the K-39 NMR parameters of KAB and several K-containing materials by using the gauge-including projector augmented wave (GIPAW) approach, and found that the precise theoretical predictions and assignments of K-39 NMR parameters were possible. The DFT-GIPAW calculations were successfully applied to assign the K-39 MAS NMR signals of KAB to the crystallographically inequivalent K1 and K2 sites.