RIKEN SPring-8 Center , RIKEN, 1-1-1 Koto, Hyogo 679-5148, Japan ; Fukushima Renewable Energy Institute , AIST, Fukushima 963-0215, Japan.
RIKEN SPring-8 Center , RIKEN, 1-1-1 Koto, Hyogo 679-5148, Japan ; Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University , Kyoto 606-8501, Japan.
R Soc Open Sci. 2015 Jul 29;2(7):150006. doi: 10.1098/rsos.150006. eCollection 2015 Jul.
The ability to design and control properties of nano-sized space in porous coordination polymers (PCPs) would provide us with an ideal stage for fascinating physical and chemical phenomena. We found an interconversion of nuclear-spin isomers for hydrogen molecule H2 adsorbed in a Hofmann-type PCP, {Fe(pz)[Pd(CN)4]} (pz=pyrazine), by the temperature dependence of Raman spectra. The ortho (o)-para (p) conversion process of H2 is forbidden for an isolated molecule. The charge density study using synchrotron radiation X-ray diffraction reveals the electric field generated in coordination nano-space. The present results corroborate similar findings observed on different systems and confirm that o-p conversion can occur on non-magnetic solids and that electric field can induce the catalytic hydrogen o-p conversion.
设计和控制多孔配位聚合物（PCPs）中纳米级空间的性质，将为我们提供一个探索物理和化学现象的理想平台。我们发现，在 Hofmann 型 PCP {Fe(pz)[Pd(CN)4]}（pz=吡嗪）中吸附的氢分子 H2 的核自旋异构体可以通过拉曼光谱的温度依赖性进行相互转换。对于孤立分子，H2 的顺式（o）-反式（p）转换过程是被禁止的。使用同步辐射 X 射线衍射进行的电荷密度研究揭示了在配位纳米空间中产生的电场。目前的结果与在不同系统中观察到的类似结果相吻合，并证实 o-p 转换可以在非磁性固体上发生，并且电场可以诱导催化氢的 o-p 转换。
