Crystal-to-crystal transformations of a series of isostructural metal-organic frameworks with different sizes of ligated solvent molecules

摘要

Isostructural 3D metal-organic frameworks (MOFs) [Zn_2(BTC) (NO_3)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 1D 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)(NO_3)(DMF)_3] (2), is stable in Mg ~(II)- and Co~(II)-DMF solutions; however, it transforms into a single particle-like microcrystalline aggregate of Cu-HKUST-1 in a Cu ~(II)-DMF solution.