A new zinc(II) hydrazone-hydrazide complex: synthesis, structural study, and supercapacitor application of ZnO nanoparticles derived from the complex

A new zinc(II) complex with the formula [Zn(4-Pybc)\2(CH3COO)\2(H2O)], containing a hydrazone–hydrazide ligand derived from 4-pyridinecarboxaldehyde (4-pybc) and benzyl hydrazine carboxylate, was successfully synthesized and characterized using elemental analysis, UV–Vis spectroscopy, and FT-IR spectroscopy. Single-crystal structural analysis revealed that the complex consists of monomeric octahedral units, where the Zn(II) center is coordinated by two pyridine-N atoms (N1, N4) from the 4-Pybc ligands, one water molecule (O9), and two acetate anions, forming a complete asymmetric unit. Well-crystalline, uniformly sized, porous ZnO nanoparticles were obtained through thermal decomposition of the complex at 800 °C for 2 h in air. The resulting ZnO nanoparticles were examined using PXRD, SEM, and TEM analyses. Furthermore, a ZnO–graphene oxide (ZnO–GO) composite was fabricated and investigated for supercapacitor applications. With a remarkable specific capacitance of 1098 F g−1, the ZnO–GO nanocomposite demonstrated its great potential for energy storage systems.