Walenszus Francesco, Bon Volodymyr, Evans Jack D, Kaskel Stefan, Dvoyashkin Muslim
Department of Inorganic Chemistry, Technische Universität Dresden, 01069 Dresden, Germany.
Institute of Chemical Technology, Universität Leipzig, 04103 Leipzig, Germany.
J Phys Chem Lett. 2020 Nov 19;11(22):9696-9701. doi: 10.1021/acs.jpclett.0c02745. Epub 2020 Nov 2.
In situ H pulsed field gradient (PFG) NMR was used to investigate the molecular diffusion of -butane in the pores of the flexible metal-organic framework DUT-49(Cu) at 298 K at different pore loadings, including pressure ranges below and above the negative gas adsorption (NGA) transition caused by structural contraction of the material. Supported by molecular dynamics simulations, the investigation provided crucial insight into confined diffusion within a highly flexible pore environment. The self-diffusion coefficients were derived from the experiment and compared with simulations, capturing the diffusion during -butane adsorption and desorption. This complementary approach has yielded experimental characterization of molecular diffusion mechanisms during the unique process of NGA. This includes the observation of a 4-fold decrease of diffusivity within a less than 2 kPa gas pressure variation, corresponding to the NGA transition point.
原位氢脉冲场梯度（PFG）核磁共振技术被用于研究298K下不同孔负载量时正丁烷在柔性金属有机骨架材料DUT-49（Cu）孔中的分子扩散情况，包括低于和高于由材料结构收缩引起的负吸附（NGA）转变的压力范围。在分子动力学模拟的支持下，该研究为高度柔性孔环境中的受限扩散提供了关键见解。自扩散系数通过实验得出并与模拟结果进行比较，记录了正丁烷吸附和解吸过程中的扩散情况。这种互补方法对NGA独特过程中的分子扩散机制进行了实验表征。这包括观察到在小于2kPa的气压变化范围内扩散率下降了4倍，该气压变化对应于NGA转变点。
