Two Solvent-Dependent Zinc(II) Supramolecular Isomers: Rare kgd and Lonsdaleite Network Topologies Based on a Tripodal Flexible Ligand

Two Zn(II) supramolecular isomeric metal–organic frameworks (MOFs) based on well-designed tripodal tris(2-carboxyethyl)isocyanuric acid (H3tci), formulated as [(Me2NH2)Zn(tci)·0.5DMF]n (1) and [(Me2NH2)Zn(tci)·2DMF]n (2) (Me2NH2 = protonated dimethylamine, DMF = N,N-dimethylformamide) have been solvothermally synthesized and characterized. Compounds 1 and 2 are supramolecular isomers controlled by solvent systems and exhibit a structural progression from a rare two-dimensional kgd sheet to a three-dimensional framework with unusual Lonsdaleite (lon) topology. The structural dissimilarity between them was dependent on the coordination environments of the Zn(II) ion and linking modes of the tci ligand influenced by solvent systems. The photoluminescence behaviors of 1 and 2 are also discussed.