New Homo and Heterobinuclear Macrocyclic Complexes Bearing Isatine Structural Characterization, Thermal Study and DFT Calculations

Abstract
A new metal-free macrocyclic Schiff base ligand bearing two metal cavities incorporated with two sets of N3O2 donor atoms derived from 2, 6-diaminopyridine and isatine was synthesized. The new ligand was used to prepare homo and hetero binuclear macrocyclic Schiff base complexes with Ni (II), Cu (II), ZrO (II) and Ba (II) metal ions. The ligand and metal complexes were characterized using Fourier transform infrared (FT-IR), UV–vis, mass spectroscopy, elemental analysis (CHN), thermo gravimetric analysis (TGA), magnetic susceptibility, and molar conductivity measurements. The DFT calculations using the B3LYP functional method have been applied to obtain the geometry and electronic properties of the ligand and its metal complexes to support the experimental data. To describe the reactivity of the title molecules, the HOMO and LUMO levels and Mulliken atomic charges were determined.