A New Cyanofluorene–Triphenylamine Copolymer: Synthesis and Photoinduced Intramolecular Electron Transfer Processes

✍ Scribed by Ying Lin; Mohamed E. El-Khouly; Yu Chen; Mustafa Supur; Lingling Gu; Yongxi Li; Shunichi Fukuzumi

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 497 KB
• Volume: 15
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200900752

✦ Synopsis

Abstract

A new π‐conjugated copolymer, namely, poly{cyanofluore‐alt‐[5‐(N,N′‐diphenylamino)phenylenevinylene]} ((CNF–TPA)~n~), was synthesized by condensation polymerization of 2,2′‐(9,9‐dioctyl‐9H‐fluorene‐2,7‐diyl)diacetonitrile and 5‐(N,N′‐diphenylamino)benzene‐1,3‐dicarbaldehyde by using the Knoevenagel reaction. By design, diphenylamine, alkylfluorene and poly(p‐phenylenevinylene) linkages were combined to form a (CNF–TPA)~n~ copolymer which exhibits high thermal stability and glass‐transition temperature. Photodynamic measurements in polar benzonitrile indicate fast and efficient photoinduced electron transfer (≈10^11^ s^−1^) from triphenylamine (TPA) to cyanofluorene (CNF) to produce the long‐lived charge‐separated state (90 μs). The finding that the charge‐recombination process of (CNF^.−^–TPA^.+^)~n~ is much slower than the charge separation in polar benzonitrile suggests a potential application in molecular‐level electronic and optoelectronic devices.