Hydrogen bond networks in Cs2(HSO4)(H2PO4) as studied by solid state NMR
Hydrogen bond networks in Cs2(HSO4)(H2PO4) as studied by solid state NMR
复制标题
通过固态 NMR 研究 Cs2(HSO4)(H2PO4) 中的氢键网络
DOI：
10.1021/acs.jpcc.7b03824
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
治村 圭子
中科院分区：
文献类型：
--
作者：
林 繁信;治村 圭子
无机固体酸盐Cs2（HSO 4）（H2 PO 4）在高于370 K的超质子相中显示出高质子导电性，并且该相即使在室温下冷却也能保持很长时间。这些特性应该与连接SO 4和PO 4基团的氢键网络相关。在本工作中，氢键网络的结构进行了研究，通过固体核磁共振。我们提出了31 P，1H和133 Cs魔角旋转（MAS）NMR谱，31 P静态NMR谱推导化学位移各向异性，31 P {1H}偶极退相实验，和1H {31 P}旋转回波双共振（REDOR）实验。~（31）P核磁共振谱表明，所有的P位在晶体学上都是等价的，化学位移各向异性的负值表明在PO 4四面体周围形成了四个氢键。~（31）P {1H}偶极退相实验强烈支持PO_4四面体周围的氢键数为4。~ 1H和~（133）Cs MASNMR谱表明，部分氢键网络是无序的，且无序结构随时间缓慢弛豫。在这些核磁共振结果的基础上，我们提出了一个氢键网络的模型结构。
The inorganic solid acid salt Cs2(HSO4)(H2PO4) showed high proton conductivity in the superprotonic phase above 370 K, and the phase was retained on cooling even at room temperature for a long period. These characteristic properties should correlate to the hydrogen bond network connecting the SO4and PO4groups. In the present work, the structures of the hydrogen bond network were studied by solid-state NMR. We present31P,1H, and133Cs magic-angle-spinning (MAS) NMR spectra,31P static NMR spectra to derive chemical shift anisotropy, a31P{1H} dipolar dephasing experiment, and1H{31P} rotational-echo double resonance (REDOR) experiments. The31P NMR spectra indicate that all the P sites are crystallographically equivalent, and the negative value of the chemical shift anisotropy suggests that four hydrogen bonds are formed around the PO4tetrahedron. The31P{1H} dipolar dephasing experiment strongly supports that the number of hydrogen bonds around the PO4tetrahedron is four. The1H and133Cs MAS NMR spectra show that a part of the hydrogen bond network is disordered and that the disordered structure relaxes slowly with time. On the basis of those NMR results, we propose a model structure of the hydrogen bond network.