Synthesis, characterization, and ring-opening polymerization of a novel [1]silaferrocenophane with two ferrocenyl substituents at silicon

摘要: Abstract Reaction of dichlorodiferrocenylsilane, Fc2SiCl2 (4) (Fc=(η-C5H4)Fe(η-C5H5)), with dilithioferrocene fcLi2·TMEDA (fc=(η-C5H4)2Fe, TMEDA=N,N,N,N-tetramethylethylenediamine) afforded the novel trimetallic [1]silaferrocenophane 5, fcSiFc2, in 77% yield. A single crystal X-ray diffraction study ferrocenophane 5 showed presence significant disorder but revealed that molecule possesses a highly strained structure where tilt-angle between planes cyclopentadienyl rings is 20–22°, typical silicon-bridged [1]ferrocenophanes. The Fe⋯Fe distances are 5.434, 5.537, and 5.687 A, metal–metal interactions evident as redox coupling was detected cyclic voltammogram this species. Differential pulse voltammetry resolved three oxidation waves at 0, 0.22, 0.45 V relative to ferrocene/ferrocenium couple. Mossbauer spectroscopy proved useful corroborating two distinct Fe environments present were readily (δ=0.424(5) mm s−1, d, ΔEq=2.242(5) 2 Fe; δ=0.414(5) ΔEq=1.930(5) 1 Fe). Further characterization by IR Raman also undertaken. Ring-opening addition HCl across Si–C bond chlorotriferrocenylsilane, Fc3SiCl (6), 81% Subsequent hydrolysis 6 silanol Fc3SiOH (7) ferrocenyl substituents. Single 7 compound crystallizes hydrogen-bonded dimers. When heated, found undergo thermal ring-opening polymerization (ROP) afford oligomeric species [fcSiFc2]x (9x, x=2 or 3) an insoluble polymeric material [fcSiFc2]n (8). Copolymers 10 obtained when heated dimethyl[1]silaferrocenophane, fcSiMe2 (1a)