General reaction scheme is shown below. In the spectra , a low intensity absorption peaks was observed in the range of 400-560 cm -1 because of the stretching frequency of metal-oxygen and metal-nitrogen bonds. The ν(S=O) shows up near 1076 cm -1 as a highly intense peak in free omeprazole, while in the complex the corresponding peak was found at somewhat lower frequency area in Cu(II) and Hg(II) complexes.