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(η(5)‐C(5)H(4))(η(5)‐C(5)H(5))) 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°′=−130 mV) and 7 a (E°′=50 mV) influences the redox potentials, whereas the ones of 5 b and 7 b (E°′=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.