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‐Fc2‐ (5 b ), 2,7‐Fc2‐pyrene (7 b ), 3,6‐Fc2‐9,10‐phenanthrenedione (10 ), and 3,6‐Fc2‐9,10‐dimethoxyphenanthrene (12 ; Fc=Fe(i5‐C5H4)(i5‐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 °'=−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 FeII/FeIII 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.