Nine novel Ln(Ⅲ) complexes with Schiff base (ACACDA) derived from diethylene glycol diamine and acetylacetone have been synthesized by the "step by step" method for the first time. They can be formulated as: [Ln(ACACDA)~2(NO~3)](NO~3)~2·4H~2O (Ln=La, Pr, Nd, Sm, Gd, Tb, Er, Yb, Y). Enamic form mechanism in the ligand of the complexes was suggested and proved by UV, IR, especially ^1H and ^1^3C NMR spectra. The EPR spectrum of the Gd(Ⅲ) complex exhibits the "U" spectral feature and "zero field effect". On this basis, the crystal field strength and the local symmetry around Gd^3^+ in the complex have been discussed.

Key words: RARE EARTH METAL COMPLEX, ACETOPREPANONE, SCHIFF BASE, ETHER, STRAIGHT CHAIN, RARE ELEMENT, ENAMINES, β-DIKETONES, SPECTROMETRIC ANALYSIS, SYNTHESIS