Photolysis of a C6D6 solution of CpFe(CO)2SiMe2SiMe3 (Cp=η5-C5H5) or (MeCp)Fe(CO)2SiMe2SiMe3 (MeCp=η5-C5H4Me) resulted in the formation of monosilyl derivative, CpFe(CO)2SiMe3 or (MeCp)Fe- (CO)2SiMe3 in 64 or 59% yield, respectively, together with small quantities of ferrocene and Cp2Fe2(CO)4 or their methylated derivatives. The yield of CpFe(CO)2SiMe3 increased to 88% when the photolysis was carried out under a carbon monoxide atmosphere, while decreased to 22% when argon was vigorously bubbled through the reaction mixture. These results are consistent with a mechanism involving dissociation and recombination of a carbonyl ligand which are common processes in photoreactions of transition-metal carbonyl derivatives. Dime- thylsilylene moiety released during the photolysis was tried to be trapped with a hydrosilane, diene, and cyclotrisiloxane, but none of the expected products from the trapping reactions was detected, even in a trace amount. Photolysis of CpFe(CO)2SiMe2SiMeEt2 afforded, accompanying alkyl migration between silicon atoms, CpFe(CO)2SiMeEt2, CpFe(CO)2SiMe2Et, and CpFe(CO)2SiMe3 in 26, 33, and 4% yields, respectively. Photolysis of a 1:1 mixture of CpFe(CO)2SiMe2SiMeEt2 and (MeCp)Fe(CO)2SiMe2SiMe3 provided only products expected from intramolecular alkyl migration mechanism. A possible mechanism involving silyl(silylene)iron intermediates is proposed to explain these results.
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