A Significant Two-Dimensional Structural Transformation in a Coordination Polymer that Changes Its Electronic and Protonic Behavior

Yao Jing; Yukihiro Yoshida; Tokutaro Komatsu; Hiroshi Kitagawa

doi:10.1002/anie.202303778

A Significant Two-Dimensional Structural Transformation in a Coordination Polymer that Changes Its Electronic and Protonic Behavior

Angew Chem Int Ed Engl. 2023 Jul 17;62(29):e202303778. doi: 10.1002/anie.202303778. Epub 2023 Jun 2.

Authors

Yao Jing¹, Yukihiro Yoshida¹, Tokutaro Komatsu², Hiroshi Kitagawa¹

Affiliations

¹ Division of Chemistry, Graduate School of Science, Kyoto University Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan.
² School of Medicine, Nihon University, 30-1 Oyaguchi-Kamicho, Itabashi-ku, Tokyo, 173-8610, Japan.

PMID: 37171043
DOI: 10.1002/anie.202303778

Abstract

A 2D-to-2D (2D: two-dimensional) structural transformation accompanying significant bond rearrangement and coordination environment change is demonstrated in a coordination polymer (CP) comprised of copper(II) ions and terephthalate (BDC^2- ) ligands for the first time. When immersed in water, a free-standing membrane of 2D Cu(BDC)(DMF) (Cu-1; DMF: N,N-dimethylformamide) transforms into 2D Cu(BDC)(H₂ O)₂ (Cu-2) while maintaining its highly oriented layered structure. In the 2D sheet, paddlewheel-type Cu^II dimers coordinated with four bidentate BDC ligands in a square-planar array in Cu-1 were released to form uniform aqua-bridged Cu^II chains, which are cross-linked with each other by unidentate BDC ligands, in Cu-2. The present facile approach to implement the 2D-to-2D transformation accompanied by bond rearrangement, which is characteristic of CPs, leads to a marked increase in in-plane magnetic susceptibility and proton conductivity. In situ experiments in support of theoretical calculations unveiled the energy diagram that governs the unique structural transformation.

Keywords: 2D-to-2D Transformation; Coordination Polymer; Magnetism; Proton Conductivity.