Solid-state transformation in porous metal-organic frameworks based on polymorphic-pillared net structure: Generation of tubular shaped MOFs

A first time report on a solid-state polymorphic transformation of MOF materials [Zn 2 (bdc) 2 (dabco)] n (ZnBD) and [Co 2 (bdc) 2 (dabco)] n (CoBD) from a pillared kagomé-lattice form (ZnBD kgm or CoBD kgm ) to a pillared square-lattice form (ZnBD sql or CoBD sql ) at ambient condition is given. Several solvents were applied as a guest-driven molecule to trigger the solid-to-solid transformation while only methanol demonstrated to be able to perform this transformation. The methanol-driven solid-state transformation behavior was observed by using powder X-ray diffraction. The morphology investigated that the rod-like Kagomé form rapidly transformed into a tubular square lattice upon addition of methanol at room temperature. The characteristic porosity reconfirmed the transformation was complete. A transformation mechanism of disconnection-deformation-rebuilding was elucidated based on the experiment.