Polymorphism in High-Crystalline-Stability Metal−Organic Nanotubes

By application of mixed organic ligands of 5-amino-2,4,6-triiodoisophthalic acid (H2ATIBDC) and 4,4′-bipyridine (bpy) to assemble with Zn ions at room temperature, two novel polymorphic structures, Zn(ATIBDC)(bpy)·3H2O (denoted as MONT-1 and MONT-2), possessing one-dimensional metal−organic nanotubular structures have been synthesized and characterized. MONT-1 was generated by connection of the zero-dimensional Zn-bpy squares through the bridging ATIBDC ligands, while MONT-2 was formed by connection of the one-dimensional Zn-bpy helix through the ATIBDC ligands. Both nanotubes possess highly crystalline stabilities and can absorb the uncoordinated water molecules reversibly.