Design and generation of extended zeolitic metal-organic frameworks (ZMOFs): Synthesis and crystal structures of zinc(II) imidazolate polymers with zeolitic topologies

Attempts to create metal-organic frameworks (MOFs) with zeolitic topologies, metal (zinc(II) and cobalt(II)) imidazolates have repeatedly been used as the metal-organic motifs of inorganic silicate analogues. By modulating the synthetic strategy based on the solvothermal and liquid diffusion method, seven further MOFs (including at least three zeolitic MOFs) of zinc(II) imidazolates, [Zn(im)(2)center dot xG] (G=guest molecule, x=0.2-1) 1a-7a, have been successfully synthesized. Of these, 1a-3a are isostructural with the previously reported cobalt analogues 1b-3b, respectively, while 4a-7a are new members of the metal imidazolate MOF family. Complex 4a exhibits a structure related to silicate CaAl2Si2O8 of CrB4 topology, but with a higher network symmetry; complex 5a has a structure with zeolitic DFT topology that was discovered in zeolite-related materials of DAF-2, UCSB-3, and UCSB-3GaGe; complex 6a demonstrates an unprecedented zeolite-like topology with one dimensional channels with 10-rings; and 7a displays a structure of natural zeolite GIS (gismondine) topology. All of these polymorphous MOFs were created only by using certain solvents as structure-directing agents (SDAs). Further extensive metal-organic frameworks with zeolitic topologies can be envisaged if other solvents were to be used.