Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd. NW, Washington, DC 20015, USA.
J Chem Phys. 2009 Dec 14;131(22):224515. doi: 10.1063/1.3174262.
High pressure Raman spectroscopy of NH(3)BH(3)-H(2) mixtures up to 60 GPa reveals unusual pressure-induced complexation and intermolecular interactions. Stretching modes of H(2) in the complex arise at 6.7 and 10 GPa, increasing in frequency with pressure of up to 60 GPa with different pressure coefficients, and at approximately 40 GPa, the lower frequency mode approaches vibron frequency of bulk H(2). Pressure-induced transformations in pure NH(3)BH(3) studied up to 60 GPa reveal a disorder-order transition at 1 GPa (phase II) and further transitions at 5 (phase III) and 10 GPa (phase IV). The spectra of both pure NH(3)BH(3) and the NH(3)BH(3)-H(2) complex provide evidence for strengthened of the N-H(delta+)...H(delta-)-B dihydrogen bonding linkages up to 50 GPa, beyond which they weaken. The dihydrogen bonding breaks down due to interactions with H(2) between 15 and 20 GPa in the NH(3)BH(3)-H(2) complex. The behavior of the nu(NH(3)) modes in the NH(3)BH(3)-H(2) complex indicates a dominant role of the NH(3) functional group in the observed interactions.
高压拉曼光谱研究了 NH(3)BH(3)-H(2)混合物在 60 GPa 以下的情况，结果表明其存在异常的压力诱导络合和分子间相互作用。复合物中 H(2)的伸缩模式出现在 6.7 和 10 GPa，随着压力的增加频率增加到 60 GPa，压力系数不同，在大约 40 GPa 时，低频模式接近体相 H(2)的振动频率。在 60 GPa 以下研究纯 NH(3)BH(3)的压力诱导转变，发现在 1 GPa 处存在无序-有序转变（第二相），进一步在 5 GPa（第三相）和 10 GPa（第四相）处存在转变。纯 NH(3)BH(3)和 NH(3)BH(3)-H(2)复合物的光谱均提供了证据，证明在 50 GPa 以下，N-H(delta+)...H(delta-)-B 双氢键键合增强，超过此压力则减弱。双氢键由于在 NH(3)BH(3)-H(2)复合物中在 15 至 20 GPa 之间与 H(2)相互作用而断裂。NH(3)BH(3)-H(2)复合物中 nu(NH(3))模式的行为表明 NH(3)官能团在观察到的相互作用中起主导作用。
