Construction of 3D supramolecular networks based on 1D chains from flexible bis(imidazolyl) and 4-hydroxybenzolate

The reaction of 1,2-bis(imidazol-1′-yl)ethane (bime), 4-hydroxybenzoic acid (HO-HBC) with different metal salts in water/ethanol gave rise to three supramolecular architectures [M(HO-BC)2(H2O)2(bime)]n [M = Mn(II), Co(II) and Ni(II)]. Single crystal X-ray diffraction analysis reveals that complexes 1-3 are isomorphous and are 3D supramolecular networks. HO-BC serves as a monodentate ligand through one carboxylate oxygen atom coordinating to metal center. The extensive hydrogen bonds from HO-BC and coordination water result in the formation of 3D supramolecular networks. The gauche-conformational bime connects the neighboring metal ions into 1D chain, which is located in the large void of the 3D networks. The thermogravimetric analysis reveals that complexes 1-3 are stable before 273 °C. Magnetic analysis shows that there are no interactions between neighboring metal ions.