the trichlorides of lanthanum, neodymium, samarium and gadolinium reacted with an equivalent [C~5H~4C(CH~3)(C~2H~5)CH~2CH＝CH~2]MgCl in THF at room temperature for 12 h to give 1-methyl-1-ethyl-3-butenyl cyclopentadienyl lanthanide dichloride complexes. Their constitutional formula were characterized by elementary analyses, MS, IR and ^1H NMR to be [C~5H~4C(CH~3)(C~2H~5)CH~2CH＝CH~2]LnCl~2· MgCl~2· THF[Ln=La(1), Nd(2), Sm(3), Gd(4)].

Key words: CYCLOPENTADIENE P, ELEMENTAL ANALYSIS, MASS SPECTROGRAPHY, INFRARED SPECTROPHOTOMETRY, NMR SPECTROMETRY, NEODYMIUM COMPLEX, LANTHANUM COMPLEX, SAMARIUM COMPLEX, GADOLINIUM COMPLEX