Synthesis, Structural Characterization, and Water Vapor Sorption Behavior of Two Ligand Ratio-Dependent Supramolecular Networks, [Cd(2,2'-bpym)1.5(BDC)]·0.5(2,2'-bpym)·5H2O and [Cd(2,2'-bpym)0.5(BDC)(H2O)3]

Chih-Chieh Wang; Geng-Min Lin; Cheng-Han Lin; Tsai-Wen Chang; Szu-Yu Ke; Chuan-Yien Liu; Gene-Hsiang Lee; Bo-Hao Chen; Yu-Chun Chuang

doi:10.1021/acsomega.2c00652

Synthesis, Structural Characterization, and Water Vapor Sorption Behavior of Two Ligand Ratio-Dependent Supramolecular Networks, [Cd(2,2'-bpym)_1.5(BDC)]·0.5(2,2'-bpym)·5H₂O and [Cd(2,2'-bpym)_0.5(BDC)(H₂O)₃]

ACS Omega. 2022 Apr 14;7(16):14089-14101. doi: 10.1021/acsomega.2c00652. eCollection 2022 Apr 26.

Authors

Chih-Chieh Wang¹, Geng-Min Lin², Cheng-Han Lin¹, Tsai-Wen Chang¹, Szu-Yu Ke¹, Chuan-Yien Liu¹, Gene-Hsiang Lee³, Bo-Hao Chen⁴, Yu-Chun Chuang⁴

Affiliations

¹ Department of Chemistry, Soochow University, Taipei 11102, Taiwan.
² Department of Chemistry and Center for Emerging Material and Advanced Devices, National, Taiwan University, Taipei 10617, Taiwan.
³ Instrumentation Center, National Taiwan University, Taipei 10617, Taiwan.
⁴ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.

Abstract

Two ligand ratio-dependent supramolecular networks, [Cd(2,2'-bpym)_1.5(BDC)]·0.5(2,2'-bpym)·5H₂O (1) and [Cd(2,2'-bpym)_0.5(BDC)(H₂O)₃] (2), (BDC^2- = dianion of terephthalic acid and 2,2'-bpym = 2,2'-bipyrimidine) have been synthesized and structurally characterized by the single-crystal X-ray diffraction method. Structural determination reveals that compound 1 is a two-dimensional (2D) layered metal-organic framework (MOF) constructed via the bridges of Cd(II) ions with 2,2'-bpym and BDC^2- ligands, and compound 2 is a zero-dimensional (0D) 2,2'-bpym-bridged di-Cd(II) monomeric complex. When the thermally dehydrated powders of 1 (at 100 °C) were immersed into water solution, most of the dehydrated powders of 1 underwent structural transformation back to rehydrated 1, but very little amounts of the dehydrated powders of 1 were decomposed to light-brown crystals of 2 or colorless crystals of a new coordination polymer (CP), [Cd(2,2'-bpym)(BDC)(H₂O)]·3H₂O (3), with its one-dimensional (1D) zigzag chain-like framework being constructed via the bridges of Cd(II) ions with the BDC^2- ligand. Structural analysis reveals that all 3D supramolecular networks of 1-3 are further constructed via strong intermolecular interactions, including hydrogen bonds and π-π stacking interactions. Compounds 1 and 2 both exhibit significant water vapor hysteresis isotherms, and their cyclic water de-/adsorption behavior accompanied with solid-state structural transformation has been verified by de-/rehydration TG analyses and powder X-ray diffraction (PXRD) measurements.