Synthesis and characterization of poly(ferrocenylsilane)s and their charge transfer salts

A novel series of poly(ferrocenylsilane)s (PFSs), i.e., poly(ferrocenylmethyl(N-ethyl-N-phenyl)propylsilane) (4a), poly(ferrocenylmethyl(3-(4-methoxylphenyl)propylsilane)) (4b), and poly(ferrocenylmethyl (3-(9-carbazolyl)propylsilane)) (4c), were synthesized by transition-metal-catalyzed ring-opening polymerization (ROP) of the corresponding substituted [1]silaferrocenophanes (3a-c). They were characterized by H-1 and C-13 NMR, FT-IR, elemental analysis, GPC, DSC, TGA, and cyclic voltammetry. Attempts have been made to dope PFSs 4 with 7,7,8,8-tetracyano-p-quinodimethane (TCNQ), chloranil (CA), tetracyanoethylene (TONE), and iodine. Only iodine and TONE were able to form charge transfer salts 5a-c and 6a-c, respectively. FT-IR, elemental analysis, and Mossbauer spectra results showed partially oxidized states for 5a-c and 6a-c, and magnetic measurements by a SQUID magnetometer demonstrated paramagnetic behavior with significant antiferromagnetic interactions for these complexes over a wide temperature range.