The characteristic V=O stretching frequency in the VO(salen) complex appears at980 cm-1, within the range 970–997 cm-1 reported for similar oxovanadium (IV)complexes [31, 32]. The O–H stretching frequency of the free ligand at 2,589 cm-1is absent, as expected, in the spectrum of the coordinated ligand, confirming theassignment to a hydrogen bridge. On coordination of the Schiff base ligand, theC=N stretching frequency is shifted to lower frequency, 1,535 cm-1, indicating adecrease in the C=N bond order due to coordination of vanadium with azomethinenitrogen lone pair [23]. This effect is supported by the presence of a new absorptionpeak at 561 cm-1 attributed to the V–N stretching frequency, which was not foundin the spectrum of the free ligand
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