Highly-strained [1]metallocenophanes have been reported to undergo photoinduced Fe-Cp bond cleavage that initially produces a species containing a tethered cyclopentadienyl anion.^1,2 Reaction of this anion with the parent compound can initiate living ring-opening polymerization to yield high molecular-weight polymetallocenes with metal atoms in the main chain. We have been investigating the primary photochemical reactions in silicon-bridged [1]ferrocenophanes and find evidence that more than one bond-cleavage process can occur depending on the solvent and photoexcitation wavelength. Quantum yields measured under a variety of experimental conditions and detailed analyses of photoproducts support this conclusion. These data offer new insights concerning the photoreactivity patterns of [1]metallocenophanes.  

                                                                                                                                                                                                          ¹K. Miyoshi, et al.  J. Am. Chem. Soc. 2003, 125, 2068-2069.

²M. Tanabe and I. Manners  J. Am. Chem. Soc. 2004, 126, 11434-11435.