General Methods in Synthesis of Polyfluorene Homopolymers

Parent (unsubstituted) PF was first synthesized electrochemically by anodic oxidation of fluorene in 1985 [266] and electrochemical polymerization of various 9-substituted fluorenes was studied in detail later [220,267]. Cyclic voltammogram of fluorene ( r1ed= 1.33 V, Eox = 1.75 V vs. Ag/Ag+ in acetonitrile [267]) with repetitive scanning between 0 and 1.35 V showed the growth of electroactive PF film on the electrode with an onset of the p-doping process at 0.5 V (vs. Ag/Ag+). The unsubstituted PF was an insoluble and infusible material and was only studied as a possible material for modification of electrochemical electrodes. For this reason, it is of little interest for electronic or optical applications, limiting the discussion below to the chemically prepared 9-substituted PFs. 

SCHEME 2.22 Oxidative coupling synthesis of poly(9,9-dihexyl)fluorene 195. (From Fukuda, M., Sawada, K., and Yoshino, K., Jpn. J. Appl. Phys., Pt. 2 — Letters, 28, L1433, 1989.) 

SCHEME 2.23 First Yamamoto synthesis of poly[9,9-fe(3,6-dioxaheptyl)fluorene]. (From Pei, Q. and Yang, Y, J. Am. Chem. Soc., 118, 7416, 1996.) 

SCHEME 2.25 Synthesis of PF via Suzuki-coupling reaction. (From Ranger, M. and Leclerc, M., Chem. Commun., 1597, 1997.) 

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