Crystal-to-Crystal Transformations of a Series of Isostructural Metal-Organic Frameworks with Different Sizes of Ligated Solvent Molecules

Isostructural 3D metal-organic frameworks (MOFs) [Zn-2(BTC)(NO3)S-3] [where BTC = 1,3,5-benzenetricarboxylate; S = EtOH (1), DMF (2), DMA (3), or DEF (4)] of a 3-connected srs net topology have been prepared in the presence of serine as a template. The MOFs show different framework stabilities depending on the sizes of the ligated solvent molecules and undergo a crystal-to-crystal transformation at ambient conditions into a ID chain structure either directly or via different types of intermediates depending on the ligated solvent molecules and the sample handling conditions. A single crystal of the MOF with the ligated DMF molecules, [Zn-2(BTC)(NO3)(DMF)(3)] (2), is stable in Mg-II- and Co-II-DMF solutions; however, it transforms into a sing,le particle-like microcrystalline aggregate of Cu-HKUST-1 in a Cu-II-DMF solution.