A Significant Two‐Dimensional Structural Transformation in a Coordination Polymer that Changes Its Electronic and Protonic Behavior
Jing Yao, Yukihiro Yoshida, Tokutaro Komatsu, Hiroshi Kitagawa
Abstract
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)(H 2 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.