Structural characterization and solvent vapor sorption of two solvent-dependent Zn(II) supramolecular architectures based on a flexible tripodal thioether-based pyridyl ligand and a dicarboxylate-based ligand

Two solvent-dependent 3D supramolecular architectures constructed by a doubly-interpenetrating layered 2D MOF of [Zn-3(L-1)(2)(L-2)(Cl)(4)(CH3OH)(2)].6CH(3)OH (1) and triply-interpenetrating 3D MOF of [Zn(L-1)(L-2)(H2O)].2C(2)H(5)OH (2) (L-1 = 1,3,5-tris(4-pyridylsulfanylmethyl)-2,4,6-trimethylbenzene and L-2 = dianion of 2,5-dihydroxyterephthalic acid), were synthesized and structurally characterized using single-crystal X-ray diffraction method. In compound 1, there were two crystallographically independent Zn(ii) ions with a distorted octahedral and a distorted tetrahedral geometries, respectively. L-1 acted as a bridge ligand with a tris-monodentate coordination connecting two Zn(ii) (Zn(1) and Zn(2)) ions to form a one-dimensional (1D) polymeric chain, genertating a [Zn2L21] metallocycle as the building unit. Adjacent chains were then connected via the bridge of Zn(ii) and L-2 with a bis-monodentate coordination mode to form a two-dimensional (2D) layered MOF. Two 2D layers mutually interpenetrated via the L-2 ligands penetrating into the [Zn2L21] metallocycle rings to genetrate a 2D doubly-interpenetrating network. In 2, the Zn(ii) ion was six-coordinate bonded to three nitrogen donors of three L-1 and three oxygen donors of two crystallographically independent L-2 and one H2O molecule to form a distorted octahedral grometry. L-1 acted as a bridge ligand with a tris-monodentate coordination connecting Zn(ii) ions to form a 2D honeycomb-like layered framework. Adjacent 2D layers were mutually connected via the bridge of Zn(ii) and L-2 with a bis-monodentate coordination mode to form a three-dimensional (3D) MOF. The much larger intraframework spaces were then occupied by the other two 3D crystallographically identical networks but independent to form a 3D triply interpenetrating supramolecular architecture. The reversible solvent vapor ad-/desorption behaviors were investigated by cyclic de-/rehydration TG analysis and the water vapor ad-/desorption isotherms of 1 and 2 were studied in detail.

Automated summary

Two solvent-dependent 3D supramolecular architectures with doubly-interpenetrating and triply-interpenetrating networks were successfully synthesized and characterized. The structures exhibited different metal coordination environments and connection modes. The solvent vapor ad-/desorption behaviors were investigated, providing insights into their properties and potential applications.