Water de/adsorption associated with single‐crystal‐to‐single‐crystal structural transformation of a series of two‐dimensional metal–organic frameworks, [M(bipy)(C4O4)(H2O)2]·3H2O (M = Mn (1), Fe (2), and Zn (3), and bipy=4,4′‐bipyridine)
作者：Chih‐Chieh Wang, Szu‐Yu Ke, Yi‐Fang Hsieh, Shih‐Ting Huang, Tzu‐Heng Wang, Gene‐Hsiang Lee, Yu‐Chun Chuang
Journal of the Chinese Chemical Society
出版：03 July 2019 (SCI)
An assembly of three metal coordination polymers (CPs), [M(bipy)(C4O4)(H2O)2]·3H2O (M = Mn (1), Fe (2), Zn (3), and bipy = 4,4′‐bipyridine, C4O42− (squarate) = dianion of H2C4O4 (squaric acid)), was synthesized and structurally characterized. Single‐crystal X‐ray structural determination reveals that compounds 1–3 are iso‐structural, in which the M(II) ions are six‐coordinate in a distorted octahedral geometry. C4O42− and bipy both act as bridging ligands with bis‐monodentate coordination mode connecting the M(II) ions to form a two‐dimensional (2D) layered metal–organic framework (MOF). Adjacent 2D layers are then arranged in parallel and interpenetrated manners to construct their three‐dimensional (3D) supramolecular architecture. Compounds 1, 2, and 3 undergo two‐step dehydration processes with the first and second weight losses of 14.1 and 8.6% for 1, of 12.1 and 7.5% for 2, and of 11.2 and 8.1% for 3, respectively, corresponding to the weight losses of the three guest water molecules and the two coordinated water molecules, and all exhibit reversible sponge‐like water de/adsorption properties during de/rehydration processes for guest water molecules as per cyclic thermogravimetric analysis (TGA). The single‐crystal‐to‐single‐crystal (SCSC) structural transformation during the reversible de/rehydration processes of three guest water molecules was identified and monitored using exhaustive single‐crystal and powder X‐ray diffraction measurements.
coordination polymer, hydrogen bonds, water ad/desorption, metal–organic framework, supramolecular architecture