title: Framework Cationization by Preemptive Coordination of Open Metal Sites for Anion-Exchange Encapsulation of Nucleotides and Coenzymes.
abstract: Cationic frameworks can selectively trap anions through ion exchange, and have applications in ion chromatography and drug delivery. However, cationic frameworks are much rarer than anionic or neutral ones. Herein, we propose a concept, preemptive coordination (PC), for targeting positively charged metal-organic frameworks (P-MOFs). PC refers to proactive blocking of metal coordination sites to preclude their occupation by neutralizing ligands such as OH(-) . We use 20 MOFs to show that this PC concept is an effective approach for developing P-MOFs whose high stability, porosity, and anion-exchange capability allow immobilization of anionic nucleotides and coenzymes, in addition to charge- and size-selective capture or separation of organic dyes. The CO2 and C2 H2 uptake capacity of 117.9 cm(3)  g(-1) and 148.5 cm(3)  g(-1) , respectively, at 273 K and 1 atm, is exceptionally high among cationic framework materials.
authors: Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, CA, 90840, USA.
authors: Xiang
authors: X
authors: Zhao
authors: Materials Science and Engineering Program, University of California, Riverside, CA, 92521, USA.
authors: Chengyu
authors: C
authors: Mao
authors: Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, CA, 90840, USA.
authors: Karen Tu
authors: KT
authors: Luong
authors: Department of Chemistry, University of California, Riverside, CA, 92521, USA.
authors: Qipu
authors: Q
authors: Lin
authors: Department of Chemistry, University of California, Riverside, CA, 92521, USA.
authors: Quan-Guo
authors: QG
authors: Zhai
authors: Department of Chemistry, University of California, Riverside, CA, 92521, USA.|Materials Science and Engineering Program, University of California, Riverside, CA, 92521, USA.
authors: Pingyun
authors: P
authors: Feng
authors: Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, CA, 90840, USA. xianhui.bu@csulb.edu.
authors: Xianhui
authors: http://orcid.org/0000-0002-2994-4051
authors: X
authors: Bu
keywords: anion separation; cationic frameworks; ion exchange; metal-organic frameworks