Living anionic polymerization of phosphorus-bridged [1]ferrocenophanes: Synthesis and characterization of well-defined poly(ferrocenylphosphine) homopolymers and block copolymers

The living anionic ring-opening polymerization (ROP) of the phosphorus-brid ged [1]-ferrocenophane (eta-C5H4)FePPh initiated by n-BuLi in THF at 25 deg rees C has allowed the preparation of well-defined poly(ferrocenylphenylpho sphines) [(eta-C5H4)(2)FePPh](n) 5, with molecular weight control, narrow p olydispersities, and controlled end-group structures. Reaction of polymers 5 with sulfur allowed the synthesis of the analogous poly(ferrocenylphenylp hosphine sulfides) [(eta-C5H4)(2)FeP(S)Ph](n) 6. Analysis of the high-molec ular-weight polymers 5 and 6 (where n = 100) by DSC showed glass-transition temperatures of 126 and 206 degrees C, respectively. The absence of melt t ransitions and the featureless WAXS profiles indicated that the materials a re amorphous. The living nature of the ROP also permitted the synthesis of well-defined block copolymers, poly(ferrocenylphenylphosphine)-b-poly(dimet hylsiloxane)(PFP-b-PDMS), PFP11-b-PDMS81 (7a) and PFP50-b-PDMS141 (7b), and poly(ferrocenylphenylphosphine)-b-poly(ferrocenyldimethylsilane) PFP11-b-P FS11 (8). Analysis of the block copolymer 7b by DSC showed the presence of individual thermal transitions for each block which indicated that they mer e incompatible. Metal coordination studies on copolymer 7b showed that this material coordinates PdCl2, to yield the insoluble copolymer 11, as well a s Fe(CO)(4), which resulted in the formation of 12 which remained soluble i n hexane.