SYNTHESIS AND REACTIVITIES OF TETRACARBON YL -[2,5-DI(TRIMETHYLSILYL)-1-METHYLCYCLOPENTADIENYL] DIIRON

2,5-Di(trimethylsilyl)-1-methylcyclopentadiene (1) was prepared by two similar reaction steps from methyl cyclopentadiene. The reaction of 1 and Fe(CO)(5) gave the expected dinuclear product a(5)-{(Me(3)Si)(2)M eC(5)H(2)}Fe(CO)](2)(mu-CO)(2), (2). 2 reacted with iodine to yield th e Fe-Fe bond cleaved iron iodide 4. 2 was reduced by Na-Hg to form the Fe-Fe bond cleaved iron anion. The anion reacted respectively with so me halides to afford the substituted iron derivatives eta(5)-[(Me(3)Si )(2)MeC(5)H(2)]Fe(CO)R (R = PhCH(2), 5;CH2COOC2H2, 6; Ph(3)Sn, 7; Ph(2 )SnCl, 8). The crystal structure of 4 was determined by X-ray crystall ography. The crystal is monoclinic, space group P2(1) / c with a = 0.7 333(1), b = 2.0089(3), c = 1.3323(4)nm; beta = 92.02 (2)degrees, V = 1 .962(1)nm(3), Z = 4, D-c = 1.57g . cm(-1).