Abstract:

Symmetric tetradentate (L1) and asymmetric pentadentate (L2) macrocyclic ligands that possess 2 dissimilar coordination sites were prepared. One has a 4-coordinate (N4) and the other has a 5-coordinate (N2O3S) donor set. Trivalent Cr(III) complexes were synthesized with L1 and L2 and their structures were investigated using elemental analyses and magnetic moment, electronic, IR, 1H NMR, 13C NMR and EPR spectra. All the Cr(III) complexes show magnetic moments corresponding to a high-spin configuration. D values indicate the energy difference between the principle bands, which are formed due to ligand field absorption. The spin-orbit coupling parameter, z, gives no significance because the splitting of doublet transition lines is too large to be explained by spin-orbit coupling. l values indicate that the complexes under study have a substantial covalent character. g-values were also calculated using the spin-orbital coupling constant, l.

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