Affiliations: Department of Chemistry, Panimalar Institute of Technology, Chennai, Tamil Nadu, India
Correspondence:
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Corresponding author: B. Anna Benedict, Associate Professor, Department of Chemistry, Panimalar Institute of
Technology, Chennai - 600 123, Tamil Nadu, India. Tel.: +91 94442 51544; E-mail: [email protected].
Abstract: A series of discrete compartmental Schiff base lanthanide(III) complexes of L2 [Ln(L2)(NO3)(H2O)] (NO3)2.2H2O (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Y) have been prepared by the condensation of Schiff bases with the precursor compounds namely, 2,6-diformyl-4-methylphenol, and 4,5-dimethyl-1,2-phenylenediamine in methanol. All the complexes have been prepared in situ from their corresponding precursor compounds by metal template method. The complexes have been characterized by elemental analysis, IR, UV, FAB spectra and magnetic studies. The yield of these complexes increases from lighter lanthanides to heavier lanthanides. The fluorescence studies were carried out for europium and terbium complexes. The results of elemental analysis of the complexes are in good agreement with the theoretical values. Conductivity studies reveal that all the complexes are 1:2 electrolytes. The metal free ligand (L1) is maroon red solid and has been characterized by IR, UV, 1H NMR, spectroscopy, elemental analysis and electron impact (EI) mass spectrometry. A reduction of two C=N bonds occurs during the synthetic procedures with the consequent formation of the partially reduced Schiff base. The metal-free macrocyclic ligand L1 does not coordinate with lanthanide(III) metal ions either at normal temperature or under refluxing conditions in ethanol, methanol, acetonitrile, chloroform or nitromethane.
Keywords: Macrocyclic complexes, lanthanide complexes, compartmental macrocycles, schiff base macrocycles
