Three-Dimensional Metal-Organic Network Glasses from Bridging MF62- Anions and Their Dynamic Insights by Solid-State NMR

Takuya Kurihara; Kotaro Ohara; Kentaro Kadota; Hitoshi Izu; Yusuke Nishiyama; Motohiro Mizuno; Satoshi Horike

doi:10.1021/acs.inorgchem.2c02580

Three-Dimensional Metal-Organic Network Glasses from Bridging MF₆^2- Anions and Their Dynamic Insights by Solid-State NMR

Inorg Chem. 2022 Oct 10;61(40):16103-16109. doi: 10.1021/acs.inorgchem.2c02580. Epub 2022 Sep 26.

Authors

Takuya Kurihara^{1

2}, Kotaro Ohara³, Kentaro Kadota², Hitoshi Izu², Yusuke Nishiyama^{4

5}, Motohiro Mizuno^{6

7}, Satoshi Horike^{2

3

8}

Affiliations

¹ Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
² Institute for Integrated Cell-Material Sciences, Institute for Advanced Study, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
³ Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
⁴ RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan.
⁵ JEOL RESONANCE Inc., Akishima, Tokyo 196-8558, Japan.
⁶ Nanomaterials Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
⁷ Institute for Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
⁸ Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand.

PMID: 36154003
DOI: 10.1021/acs.inorgchem.2c02580

Abstract

Glassy-state coordination polymers (CPs) are a new class of network-forming glasses. In this work, we constructed glass-forming CPs composed of both anionic and neutral ligands as network formers. With the use of hexafluoro anions (MF₆^2-) and 1,3-bis(4-pyridyl)propane (bpp), two isostructural CP crystals, [Zn(SiF₆)(bpp)₂] (ZnSi) and [Zn(TiF₆)(bpp)₂] (ZnTi), were synthesized. Solid-state ¹⁹F NMR revealed rotational motion of MF₆^2- with dissociation and re-formation of the Zn-F coordination bonds in both CP crystals, which reflects the thermodynamic parameters related to the glass formability. The mobility of SiF₆^2- is larger than that of TiF₆^2-, suggesting a higher glass formability of ZnSi. When mechanical ball milling was conducted, ZnSi completely changed into a glassy state, whereas ZnTi showed incomplete glass formation. Examination of the amorphous structures elucidated retention and partial destruction of the Zn-F coordination bonds in ball-milled ZnSi and ZnTi, respectively. These results provide the relationship between the ligand dynamics and glass formability of CPs.