Abstract: The following complexes were prepared by reaction of anhydrous rare earth trichlorideswith[2,4- (CH₃)₂C₅H₅]K and characterized by elmental analysis, IR, NMR, themal analysis,X-ray diffraction analysis as well as chemical analysis of the hydrolysis products: [2,4-(CH₃)₂C₅H₅]LnCl₂·3THF (Ln = Nd, Sm, Gd), [2,4-(CH₃)₂C₅H₅]₂LnCl·THF (Ln = Nd, Sm), [2,4- (CH₃)₂C₅H₅]₃Ln (Ln = La, Sm, Gd),(2,4-(CH₃)₂C₅H₅ = 2,4-dimethylpentadienyl; THF = tetrahydrofuran).The complexes are soluble in THF and insoluble in petrolum ether.They are moisture-and air-sensitive.

Key words: dimethylpentadiene, lantanide complexes synthesis