The xylene solution of tris (trimethylsilyl) cyclopentadiene and Fe(CO)~5 was refluxed for 6h . The reaction was stopped at intermediate step of formation of the corresponding mononuclear iron hydride η-[ (Me~3SiC~5H~2] Fe(CO)~2H (1). 1 cannot proceed further to form the dinuclear (Fe-Fe) product. It is probably due to the steric effect of three silyl groups on Cp-ring which hindered the further progress of the reaction. 1 reacted respectively with CHCl~3, NBS and iodine to afford the corresponding iron halides η-[1,2,4- (Me~3SiC~5H~2) ] Fe(CO)~2X (X: Cl, 2; Br, 3; I, 4). The crystal structure of 2 was determined by X-ray crystallography.

Key words: SYNTHESIS, CRYSTAL STRUCTURE, CYCLOPENTADIENE, TRIMETHYLSILANES