Spectral properties of some 4-substituted pyridine n-oxide complexes with iron perchlorate

Visible, infrared and Mossbauer spectra of 4-substituted pyridine N-oxide complexes of the formula [Fe(4-ZC 5 H 4 NO) 6 ](ClO 4 ) 2 , where Z = OCH 3 , CH 3 , H, Cl and NO 2 are reported. Spectral data indicate that the six coordinated complexes are of high-spin octahedral structure distorted from O h symmetry. From infrared spectral measurements metal-oxygen stretching vibrations are found to be correlated with the σ pyNO values of the ligand. Crystal field parameters are evaluated from diffuse reflectance spectra and the trend of parameter was discussed in terms of spectrochemical series.