title: A guest-dependent approach to retain permanent pores in flexible metal-organic frameworks by cation exchange.
abstract: Two anionic metal-organic frameworks were successfully prepared based on pre-designed flexible multicarboxylate ligands and indium cations. Owing to the flexibility of the bridging organic linkers, which could not themselves sustain the frameworks, both of the frameworks showed thermal instability and shrinkage after removal of guest solvent molecules. Inspired by bamboo, we used a guest-dependent approach to tune the permanent porosity of the MOFs. In this approach, several tetraalkyammonium cations of different sizes were introduced into the channels by cation exchange to act as partitions and to support the main frameworks. This approach significantly enhanced the stability of the framework and its permanent porosity. Moreover, the gas-adsorption properties (such as gate sorption, hysteresis, and selectivity) of the MOFs were also modulated by the judicious choice of guest cations.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fujian, Fuzhou, 350002, PR China.
authors.forename: Zu-Jin
authors.initials: ZJ
authors.lastname: Lin
authors.forename: Tian-Fu
authors.initials: TF
authors.lastname: Liu
authors.forename: Yuan-Biao
authors.initials: YB
authors.lastname: Huang
authors.forename: Jian
authors.initials: J
authors.lastname: Lü
authors.forename: Rong
authors.initials: R
authors.lastname: Cao