Spectroscopic, Crystallographic and Thermal Comparison of Two Asymmetric Tridentate Schiff Base Molecules

Two similar asymmetric ONO type tridentate Schiff Base ligand molecules and their spectroscopic, crystallographic and thermal properties are comparised. Both of molecules obtained in the study were characterized by 1H-NMR, 13C-NMR, thermal analysis, IR spectroscopy and UV-Vis spectroscopy. However molecules were able to be obtained as single crystals and their structures were determined by single crystal X-ray technique. The space group of the geometric shape of the 2'-(2-hydroxy-anilidene)-4-hydroxy-pentane (L1) ligand is P212121. There are 4 molecules in the unit cell of the crystal system of the L1 ligand. The space group of the geometric shape of the 4'(2-hydroxy-5-chlorine-anilidene)-2-hydroxy-pentane (L2) ligand is P21/c. There are four molecules in the unit cell of the crystal system of the ligand. Although they are ligands with similar structure, L1 ligand has an orthorhombic unit cells and L2 ligand has a monoclinic unit cells. Thermal analysis of the ligands showed a state change point. L1 and L2 ligands degraded in a single step. The 1H-NMR spectra of the L1 and L2 ligands, which have similar structures, are similar in outline. However, it is interesting to observe that the peaks of these carbons are observed in a higher area since the chlorine atom attached to the aromatic ring in the L2 ligand increases the screening effect.. The spectroscopic results also show a general similarity, but the effect of the chlorine atom stands out.