Novel solvent-triggered transformation of Cu-based metal-organic gels to highly monodisperse metal-organic frameworks with controllable shapes

The transformation of amorphous phase metal-organic gels (MOGs) into crystal metal-organic frameworks (MOFs) is an expectant and effective strategy for crystal growth. Herein, a novel solvent-triggered method on transforming amorphous copper-based metal-organic gels (Cu-MOGs) into highly monodisperse MOFs crystals with controlled shapes, namely, dodecahedron, hollow dodecahedron, polyhedron, cube, cruciate flower and cross star, was developed in a mild condition. The stoichiometric ratio of metal ions to ligands in Cu-MOGs and the constituent of solvent were both demonstrated to play unique and key roles in determining the final shape of the MOFs crystals. Meanwhile, the crystal morphological evolution process from original fibrillar network to the multi-shape MOFs disclosed that this novel solvent-triggered transition from amorphous phase MOGs to MOFs crystalline phase were carried out in two ways (i) dissolution-recrystallization and (ii) self-assembly of the pristine fibrillar network. This novel approach successfully connects the emerging MOFs with the supramolecular gels-based soft materials, opening up exciting ways for simple and efficient synthesis of MOFs materials.