Coordination Geometry Changes in Amorphous Cyanide-Bridged Metal-Organic Frameworks upon Water Adsorption

Haruka Yoshino, Kohei Yamagami, Hiroki Wadati, Hirona Yamagishi, Hiroyuki Setoyama, Sayuri Shimoda, Akio Mishima, Benjamin Le Ouay, Ryo Ohtani, Masaaki Ohba

研究成果: Contribution to journalArticle査読

2 被引用数 (Scopus)

抄録

Amorphous coordination polymers and metal-organic frameworks (MOFs) have attracted much attention owing to their various functionalities. Here, we demonstrate the tunable water adsorption behavior of a series of amorphous cyanide-bridged MOFs with different metals (M[Ni(CN)4]: MNi; M = Mn, Fe, and Co). All three compounds adsorb up to six water molecules at a certain vapor pressure (Pads) and undergo conversion to crystalline Hofmann-type MOFs, M(H2O)2[Ni(CN)4]·4H2O (MNi-H2O; M = Mn, Fe, and Co). The Pads of MnNi, FeNi, and CoNi for water adsorption is P/P0 = 0.4, 0.6, and 0.9, respectively. Although the amorphous nature of these materials prevented structural elucidation using X-ray crystallography techniques, the local-scale structure around the N-coordinated M2+ centers was analyzed using L2,3-, K-edge X-ray absorption fine structure, and magnetic measurements. Upon hydration, the coordination geometry of these metal centers changed from tetrahedral to octahedral, resulting in significant reorganization of the MOF local structure. On the other hand, Ni[Ni(CN)4] (NiNi) containing square-planar Ni2+ centers did not undergo significant structural transformation and therefore abruptly adsorbed H2O in the low-pressure region. We could thus define how changes in the bond lengths and coordination geometry are related to the adsorption properties of amorphous MOF systems.

本文言語英語
ページ(範囲)3338-3344
ページ数7
ジャーナルInorganic chemistry
60
5
DOI
出版ステータス出版済み - 3 1 2021

All Science Journal Classification (ASJC) codes

  • 物理化学および理論化学
  • 無機化学

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