Photolytic living anionic ring-opening polymerization (ROP) of silicon-bridged [1]ferrocenophanes via an iron-cyclopentadienyl bond cleavage mechanism.

A new living anionic ring-opening polymerization (ROP) method for sila[1]ferrocenophane 1 was developed using UV irradiation in the presence of Na[C5H5] as a promoter to afford controlled molecular weight polymers (Mn = 9.3 x 103 to 7.0 x 104, PDI = 1.04-1.21). A ring-opened ferrocenylsilane with a dangling silyl-substituted cyclopentadienyl anion, which was obtained from a near-stoichiometric photoreaction of 1 with Li[C5H4Me], indicates an Fe-Cp bond cleavage mechanism for the photolytic ROP.