Química Moderna e Aplicações

Abstrato

Catalytic Studies on Schiff Base Complexes of Co(II) and Ni(II) Using Benzoylation of Phenol

Melaku Meshesha Tulu and Ali Mohammed Yimer

The title metal complexes were found to be crystalline which have been characterized by elemental analysis, electrical conductivity, magnetic susceptibility measurements, and spectral techniques viz, UV-Visible, FT-IR and NMR (1H-NMR and 13C-NMR). These complexes were air-stable, with high melting points and were soluble in methanol and some other organic solvents such as n-hexane, diethylether and DMSO. The molar conductance of 1 × 10-3 M solutions of the metal complexes in methanol at 27°C indicates that they behave as electrolytes. Both Cobalt(II) and Nickel(II) complexes of N-benzylideneaniline ligand show paramagnetic nature. The electronic studies along with magnetic data suggest a square planer geometry for both Co(II) and Ni(II) complexes. The peak in FT-IR spectra at 1627 cm-1 confirmed the υ(C=N) stretching vibration found in the free ligand. This band was shifted to a lower frequency (1603.5 cm-1) in the spectra of the metal complexes and it confirms the participation of azomethine nitrogen in the coordination of metal ions. Finally, the metal complexes were screened for their catalytic activity in the phenol benzoylation reaction and found to be moderately active.