Abstract: A series of heteronuclear complexes of Ln(Ⅲ-)-Ni(Ⅱ) and Ni(Ⅱ) complexes with bissalicylaldehyde ethylenediamine (SALEN) have been synthesized. They are formulated as Ln₂Ni₃(SALEN)₆(NO₃)₁₂·H₂O(Ln=La,Nd,Sm,Gd,Yb,Y) and Ni₃(SALEN)₂(NO₃)₆·H₂O, respectively. The differences in their compositions, structures and coordinations have been investigated by UV, IR, magnetic susceptibility, especially by ¹H NMR and EPR spectrascopy. The EPR spectra of the Gd-Ni-SALEN complex in powder and various solvents were investigated at different temperatures. "Single Peak Effect" was observed in THF solvent at low temperature. The "U" spectral feature, crystal-field strength and local symmetry around Gd³⁺ were discussed.

Key words: Heteronuclear lanthanide complexes, Schiff base, EPR spectra