Charge Density Level Structure of Molecular Doped Functional Nano Coordination Space

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The aim of our research is to determine the precise crystal structure, including the electron densities, of nano-coordination space and adsorbed molecules by an in situ powder diffraction experiment of gas adsorption using high brilliance synchrotron light source at SPring-8 and the MEM(maximum entropy method)/Rietveld charge density analysis. Precise structural information will allow us to understand the interaction mechanism between the host framework and guest molecules in the nano-coordination space. We have revealed various crystal structures of porous coordination polymers with the adsorption of gas molecules.In hydrogen adsorption on CPL-1, the electron densities of adsorbed hydrogen molecules were clearly observed in the nanochannels. It was suggested from the result that the metal-oxygen unit is associated with an attractive interaction site for hydrogen molecules and the cavity on the pore wall well-suited to the size of hydrogen molecule is important for the effective hydrog … More en accommodation.CPL-1 was found to store acetylene with extremely high density beyond the safety compression limit at room temperature. From the MEM charge density, acetylene molecule was found to be trapped by double hydrogen bonds with the oxygen atoms on the pore wall. Furthermore, an intermediate adsorption state was also revealed for acetylene adsorption for the first time. The information on structural changes throughout the adsorption phenomena is very important and required for a feasible design of a porous framework.Recently, the electrostatic potential based on the MEM charge density was developed and was found to be useful for understanding intermolecular interaction between guest and host framework.The precise structural information obtained in this project is important for the understanding of gas adsorption phenomena in the nano-coordination space. It will also contribute to the design and the rational synthetic strategy of novel porous coordination Polymers as functional materials. Less