Cationic framework materials can selectively incorporate anions through ion exchange, and thus have potential applications in ion-chromatography or drug delivery. Unfortunately, in both natural and synthetic systems, cationic frameworks are rarely preferred during crystallization, because the formation of anionic or neutral frameworks often takes precedence. Here we propose a general concept, preemptive coordination for targeting positively charged metal-organic frameworks (P-MOFs). Specifically, this concept refers to building-block-based design schemes that proactively prevent metal coordination sites from being occupied by framework-neutralizing ligands such as OH<sup>-</sup>. We use 20 newly synthesized MOFs in 3 different framework topologies to illustrate that this concept is indeed an effective, versatile, and systematic approach for developing P-MOFs. Resulting high hydrothermal and chemical stability, high porosity, and anion-exchange capability allow immobilization of anionic nucleotides and coenzymes through anion exchange, in addition to charge- and size-selective capture or separation of organic dyes.

Synthetic design of cationic porous frameworks for anion immobilzation and separation

251st National Meeting (2016)

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