ORGANOPOLYSILANE OLIGOMERS BEARING TRANSITION-METAL MOIETIES - SYNTHESIS, REACTIVITIES AND MOLECULAR-STRUCTURE OF (CO)FE(CO)(2)FE(CO)-ETA(5)-C(5)H(4)SIME(2)SIME(3)]

Reaction of Me(3)SiMe(2)SiC(5)H(5) (4), prepared from Me(3)SiMe(2)SiCl and C5H5Na, with Fe(CO)(5) in refluxing xylene afforded the title com pound (3). The silicon-silicon bond in 3 is exceptionally stable in re fluxing xylene and also in succeeding reactions to prepare a series of its derivatives. Thus, 3 reacted with I-2 in either chloroform or ben zene, giving [eta(5)-Me(3)SiMe(2)SiC(5)H(4)Fe(CO)(2)I] (6). Compound 3 was reduced by sodium amalgam and reacted subsequently with CH3I, PhC H(2)Cl, CH3COCl, PhCOCl, Cy(3)SnCl (Cy = cyclohexyl) and Ph(3)SnCl, pr oducing [eta(5)-Me(3)SiMe(2)SiC(5)H(4)Fe(CO)(2)R] [7: R = CH3 (a), PhC H(2) (b), CH3CO (c), PhCO (d), Cy(3)Sn (e) and Ph(3)Sn (f), respective ly]. The molecular structure of 3 has been determined by X-ray diffrac tion crystallography. It was found that 3 has a trans-configuration wi th a symmetrical centre located at the middle of the Fe-Fe bond. It is abnormal that the conformation of the disilane part around the Si-Si bond is almost eclipsed rather than staggered. Copyright (C) 1996 Else vier Science Ltd