Organopolysilane oligomers bearing transition-metal moieties: Synthesis, reactivities and molecular structure of [ η5-Me 3SiMe 2SiC 5H 4(CO)Fe(CO) 2Fe(CO)- η5-C 5H 4SiMe 2SiME 3

Abstract

Reaction of Me 3SiMe 2SiC 5H 5 ( 4), prepared from Me 3SiMe 2SiCl and C 5H 5Na, with Fe(CO) 5 in refluxing xylene afforded the title compound ( 3). The silicon-silicon bond in 3 is exceptionally stable in refluxing xylene and also in succeeding reactions to prepare a series of its derivatives. Thus, 3 reacted with I 2 in either chloroform or benzene, giving [ η 5-Me 3SiMe 2SiC 5H 4Fe(CO) 2I] ( 6). Compound 3 was reduced by sodium amalgam and reacted subsequently with CH 3I, PhCH 2Cl, CH 3COCl, PhCOCl, Cy 3SnCl (Cy = cyclohexyl) and Ph 3SnCl, producing [ η 5-Me 3SiMe 2SiC 5H 4Fe(CO) 2R][7 : R = CH 3 ( a), PhCH 2 ( b), CH 3CO ( c), PhCO ( d), Cy 3Sn ( e) and Ph 3Sn ( f), respectively]. The molecular structure of 3 has been determined by X-ray diffraction crystallography. It was found that 3 has a trans-configuration with 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.