Structure Evolution and Thermal Decomposition of Supramolecular and Lamellar Hybrid Sulfates Templated by 4-Aminopyridinium

The aromatic diamine 4-aminopyridine was used for the synthesis of a series of supramolecular metal–organic sulfate salts. The obtained compounds with the formula (C5H7N2)2[MII(H2O)6](SO4)2 (MII = Fe, Co, Ni, Cu and Zn) and (C5H7N2)2[Mn(H2O)4(SO4)2] crystallize with a triclinic symmetry (S.G. P $$\overline{1 }$$ ). These complexes possess a hybrid structure type with an interlayer distance that varies from 10 to 12 A depending on the metal. The supramolecular aspect of the crystal structure is manifested through mineral layers, which are built up uniquely from hydrogen bonds. The interlayer space is filled with aromatic diamines that form chains through π⋯π interactions. The thermal study in-situ of all metal compounds revealed important stability with the formation of crystalline phases during heating. The dehydration proceeds differently according to the metal incorporated into the structure.