Synthesis, characterization, catalytic, electrochemical and thermal properties of tetradentate Schiff base complexes

In this study, the Schiff base ligands H2L1-H2L3 and their Cu-II, Co-II, Ni-II, Fe-III Ru-III and VOIV complexes have been prepared and characterized by spectroscopic and analytical techniques. All the complexes are mononuclear. Keto-enol tautomeric forms of the ligands have been investigated in polar and apolar solvents. The ligands favor the keto-form in the C7H8 and C6H14. The C-C coupling reaction of the 2,6-di-t-butylphenol has been investigated by the Co-II and Cu-II complexes. Thermal properties of the complexes have been assessed using thermal techniques and similar properties were found. In the Fe-III and Ru-III complexes, firstly, the coordinated water molecule is lost from the complex; in the second step, the chloride ion leaves the molecule in the 300-350 degrees C temperature range. Finally, the complexes decompose to the appropriate metal oxide at the higher temperature ranges. The electrochemical properties of the complexes have been studied in the two different solvents (DMF and CH3CN).