Organic-metalloblock copolymersvia photocontrolled living anionic ring-opening polymerization

A new method for the preparation of organic-organometallic diblock copolymers including a polyferrocenylsilane (PFS) metalloblock through photocontrolled ring-opening polymerization (ROP) is reported. Polystyrene (PS) homopolymers end-capped with a cyclopentadienyl group (1) were used as macroinitiators for the photocontrolled ROP of sila[1]ferrocenophanes [Fe(η-C5H4)2Si{C≡CtBu}2] 3a and [Fe(η-C5H4)2Si(Me)(C≡CSiMe3)] 3b to afford diblock copolymers with controlled molecular weights and block ratios, as well as low polydispersities (PDI < 1.2). Block copolymer PSm-b-[Fe(η-C5H4)2Si{C≡C(t-Bu)}2]n4 was clusterized with [Co2(CO)8], forming the highly metallized PSm-b-[Fe(η-C5H4)2Si{Co2(CO)6C2(t-Bu)}2]n (PS-bb-(Co-PFS), 7). The diblock PSm-b-[Fe(η-C5H4)2Si(Me)(C≡CH)]n6 was prepared by selective desilylation of PSm-b-[Fe(η-C5H4)2Si(Me)(C≡CSiMe3)]n5 was then reacted with ClAuP(n-Bu)3 in the presence of an amine as HCl acceptor to afford PSm-b-[Fe(η-C5H4)2Si(Me){C≡CAuP(n-Bu)3}]n (PS-bbb-(Au-PFS), 8). Preliminary studies on the self-assembly of these materials in thin films showed phase separation with metal-rich nanodomains within an organic matrix.