title: Lanthanide-organic cation frameworks with zeolite gismondine topology and large cavities from intersected channels templated by polyoxometalate counterions.
abstract: A family of organic-inorganic hybrid frameworks, {[Ln(H(2)O)(4)(pdc)](4)} [XMo(12)O(40)].2H(2)O (Ln = La, Ce, and Nd; X = Si and Ge; H(2)pdc = pyridine-2,6-dicarboxylate), have been prepared under hydrothermal conditions and characterized by single crystal X-ray diffraction analyses, elemental analyses, IR, and thermal gravimetric analyses. Single crystal X-ray diffraction reveals that all six compounds are isostructural, and each consists of a zeolite-like four-connected three-dimensional cationic framework {[Ln(H(2)O)(4)(pdc)](4)}(4+) and ball-shaped Keggin type [XMo(12)O(40)](4-) as templates. Interesting channels exist in the cationic framework with the gismondine topology, and these channels intersect each other to form large cavities, which array in a zigzag fashion and are occupied by nanosized [XMo(12)O(40)](4-) counterions. Moreover, these compounds display strong photoluminescent properties in the solid state at room temperature.
authors.affiliation: Department of Chemistry, The Institute for Chemical Physics, and State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Chun-Hong
authors.initials: CH
authors.lastname: Li
authors.forename: Kun-Lin
authors.initials: KL
authors.lastname: Huang
authors.forename: Ying-Nan
authors.initials: YN
authors.lastname: Chi
authors.forename: Xi
authors.initials: X
authors.lastname: Liu
authors.forename: Zhan-Gang
authors.initials: ZG
authors.lastname: Han
authors.forename: Long
authors.initials: L
authors.lastname: Shen
authors.forename: Chang-Wen
authors.initials: CW
authors.lastname: Hu