Isonicotinohydrazide conformation in a supramolecular system with 1,4-benzenedicarboxylic acid and Zn²⁺ and Mn²⁺

An anti-tuberculosis drug, isonicotinohydrazide (INH), is studied concerning its conformation in different crystalline environments. In the present work, compounds with zinc (1) and manganese (2) ions are reported where INH has different conformations, caused by hydrogen bonds with 1,4-benzenedicarboxylic acid (H₂BDC) and water molecules and by coordination bonds involving its functional groups. In 1, INH is coordinated to two zinc ions, where H₂BDC and crystallization water molecules form several hydrogen bonds giving rise to a complex three-dimensional (3-D) network. In 2, both INH and H₂BDC molecules are coordinated to manganese as well as four water molecules. The complex formed interacts by hydrogen bonds forming a 2-D arrangement. A 3-D network extension arises from other hydrogen bonds generated by crystallization water. In these two compounds, the presence of BDC ion and water molecules is very important in the stabilization of the complexes and in INH conformation. This work is focused on the structural description of formed compounds.