Abstract

Anionic metal-organic frameworks (MOFs) have attracted increasing attention due to the enhanced electrostatic interactions between their anionic frameworks and counter-ionic guests. Owing to these special host-guest interactions, anionic MOFs are beginning to have a large impact in the field of absorption and separation of ionic molecules and selective sensing of metal ions. Herein, two mesoporous anionic metal-organic frameworks, namely, [(CH3)2NH2]6[In6(OX)6(TCA)4]·solvents (JOU-11) and [(CH3)2NH2]6[In6(OX)6(TCPA)4]·solvents (JOU-12) (H3TCA = tricarboxytriphenylamine; H3TCPA = tris((4-carboxyl)phenylduryl)amine; OX = oxalate), have been synthesized by using wheel-type [In6(OX)6(COO)12]6- as building blocks. Structural analyses show that JOU-11 and JOU-12 show isoreticular three-dimensional frameworks with pyr topology. Due to their anionic frameworks and tunable pore window sizes, both compounds can be exploited for absorbing and separating cationic organic dyes. In addition, JOU-11 can be developed as a fluorescence "turn-off" sensor for selectively sensing Fe3+, whereas JOU-12 can be used for fluorescence "turn-on" sensing of Cu2+ and Co2+ ions.