An ion‐exchangeable MOF with reversible dehydration and dynamic structural behavior (NH4)2[ZN2(O3PCH2CH2COO)2]⋅5 H2O (BIRM‐1)

Research output: Contribution to journalArticlepeer-review


  • Chao Zhao
  • Louise Male
  • Joseph Barker

Colleges, School and Institutes


(NH4)2[ZN2(O3PCH2CH2COO)2]⋅5 H2O (BIRM‐1) is a new metal phosphonate material, synthesized through a simple hydrothermal reaction between zinc nitrate and 3‐phosphonopropionic acid, using urea and tetraethylammonium bromide as the reaction medium. In common with other metal–organic framework materials, BIRM‐1 has a large three‐dimensional porous structure providing potential access to a high internal surface area. Unlike most others, it has the advantage of containing ammonium cations within the pores and has the ability to undergo cation exchange. Additionally, BIRM‐1 also exhibits a reversible dehydration behavior involving an amorphization‐recrystallization cycle. The ability to undergo ion exchange and dynamic structural behavior are of interest in their own right, but also increase the range of potential applications for this material. Here the crystal structure of this new metal phosphonate and its ion exchange behavior with K+ as an exemplar are studied in detail, and its unusual structure‐reviving property reported.


Original languageEnglish
Article number201903230
Pages (from-to)13865-13868
Number of pages4
JournalChemistry: A European Journal
Issue number61
Early online date9 Oct 2019
Publication statusPublished - 4 Nov 2019


  • flexible structure, ion exchange, metal–organic frameworks, metal phosphonates, porous materials