Ferrocenyl-Pyrenes, Ferrocenyl-9,10-Phenanthrenediones, and Ferrocenyl-9,10-Dimethoxyphenanthrenes: Charge Transfer Studies and SWCNT Functionalization.

The synthesis of 1-Fc- (3), 1-Br-6-Fc- (5 a), 2-Br-7-Fc- (7 a), 1,6-Fc(2)- (5 b), 2,7-Fc(2)-pyrene (7 b), 3,6-Fc(2)-9,10-phenanthrenedione (10), and 3,6-Fc(2)-9,10-dimethoxyphenanthrene (12; Fc=Fe(eta(5)-C5H4)(eta(5)-C5H5)) is discussed. Of these compounds, 10 and 12 form 1D or 2D coordination polymers in the solid state. (Spectro)Electrochemical studies confirmed reversible Fc/Fc(+) redox events between -130 and 160 mV. 1,6- and 2,7-Substitution in 5 a (E degrees '=-130 mV) and 7 a (E degrees '=50 mV) influences the redox potentials, whereas the ones of 5 b and 7 b (E degrees '=20 mV) are independent. Compounds 5 b, 7 b, 10, and 12 show single Fc oxidation processes with redox splittings between 70 and 100 mV. UV/Vis/NIR spectroelectrochemistry confirmed a weak electron transfer between Fe-II/Fe-III in mixed-valent [5 b](+) and [12](+). DFT calculations showed that 5 b non-covalently interacts with the single-walled carbon nanotube (SWCNT) sidewalls as proven by, for example, disentangling experiments. In addition, CV studies of the as-obtained dispersions confirmed exohedral attachment of 5 b at the SWCNTs.