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Abstract
New complexes of the general compositions Ln(o-LH)3·2H2O (Ln=La, Ce, Pr, Nd, Sm), Er(o-LH)3·2.5H2O, Ln(o-LH)3·3H2O (Ln=Eu, Gd, Tb, Dy, Ho, Tm, Yb), Ln(m-LH)3·2H2O (Ln=Pr, Nd, Sm, Gd, Er), Ln(m-LH)3·3H2O (Ln=La, Ce, Eu, Tb) and Ln(m-LH)3·4H2O (Ln=Dy, Ho, Tm, Yb), where o-LH2=N-(2-carboxylphenyl) pyridine-2′ -carboxamide and m-LH2=N-(3-carboxylphenyl)pyridine-2′ -carboxamide, have been isolated. The complexes, which are probably polymeric, were characterised by elemental analyses, conductivity measurements, thermal (TG, DTG, DTA, DSC) methods, X-ray powder patterns, magnetic moments and spectral (IR, Raman, 1H-NMR, electronic diffuse reflectance and emission f-f spectra) studies. All the data are discussed in terms of the nature of the bonding and the possible structural types. The neutral secondary amide group and the ring N-atom of o-LH−and m-LH− are not coordinated to the metal ions. The carboxylate