title: Spectral studies with coordination behaviour of (NO3) and (NCS) anions and EPR parameters of chromium(III) complexes which have different chromospheres macrocyclic ligands: synthesis and electronic spectroscopy.
abstract: New macrocyclic ligands were prepared and chromium(III) stability in the marcrocyclic cavities are reported. Two of them have four-coordinate [N2O2]:[N4], third one has five-coordinate [N2O2S] and the last one has six-coordinate [N4O2] donor macrocyclic cavities. These macrocyclic ligands have been synthesized with their chromium(III) complexes which have mononuclear nature and their structural features have been discussed on the basis of: elemental analysis, magnetic moment, electronic, IR, 1H NMR, and EPR spectral studies. All the chromium(III) complexes show magnetic moments in the range of 3.74-3.80 B.M. corresponding to high-spin configuration. However, the interaction of oxygen to the chromium ion in complexes is much weaker than that of other donor atoms. The spin-orbit coupling parameter, z, gives no significance because the splitting of doublet transition lines are too large to be explained by spin-orbit coupling. The beta values (0.75-0.79) indicate the covalent character, which is due to the presence of sigma bond between the metal/ligand. lambda values indicate that the complexes under study have substantial covalent character and their g-values have also been calculated by using spin-orbital coupling constant (lambda).
authors.affiliation: Department of Chemistry, Zakir Husain College (University of Delhi) Jawahar Lal Nehru Marg, New Delhi 110002, India.
authors.forename: Sulekh
authors.initials: S
authors.lastname: Chandra
authors.forename: Rajiv
authors.initials: R
authors.lastname: Kumar
mesh_terms: D000838:Anions / Q000737:chemistry; D002857:Chromium / Q000737:chemistry*; D008024:Ligands; D047028:Macrocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D000838:Anions; D008024:Ligands; D047028:Macrocyclic Compounds; D009589:Nitrogen Oxides; D002857:Chromium