Synthesis and characterization of fluorene end‐labeled polystyrene with atom transfer radical polymerization

Abstract

Fluorene end-labeled polystyrene was prepared by atom transfer radical polymerization with 9-bromofluorene as the initiator. Reactions were carried out in bulk or tetrahydrofuran solutions at temperatures of 80 8C or above. Analysis by gel permeation chromatography indicated that the polymers formed had low polydispersities with molecular weights consistently 2-5 times higher than calculated based on monomer-to-initiator ratios. Coupling of two fluorenyl radicals, formed by activation of the 9-bromofluorene, was found to compete with initiation, leading to the higherthan-expected molecular weight values while giving rise to a fluorene dimer. UV-vis spectrometry indicated near-quantitative fluorene labeling of the polystyrene. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2657-2665, 2005

Hydrogen Abstraction Followed by Nitroxide‐Mediated Polymerization: Synthesis of 2,7‐Dibromofluorene‐Labeled Polystyrene

“…The extent of end‐group labeling was determined by UV–Vis spectroscopy using Beer–Lambert's law. The extinction coefficient for the polymer‐bound chromophore approximated to be equal to the free chromophore, which is consistent with literature reports 13, 21. Shown in Figure 3 are the absorbance traces for both the fluorene‐labeled polymer (Table 2, trial 9) along with fluorene itself.…”

“…If, rather than alkyl groups, polymer chain(s) were incorporated into the 9‐position of fluorenyl units and especially brominated fluorene‐derivatives, the resulting macromonomers could be used to create poly(fluorenes) that may resist aggregation and degradation. Previous work has outlined the synthesis of fluorene‐labeled polymers through the use of atom transfer radical polymerization (ATRP) 13. Additionally, we have used an adaption of reverse ATRP to produce high amounts of fluorene‐derivative labeled polymers, including 2‐bromofluorene and 2,7‐dibromofluorene 14.…”

A novel polyfluorene derivative electrodeposited by direct anodic oxidation of 9-bromofluorene in boron trifluoride diethyl etherate and trifluoroacetic acid

“…Although 9-bromofluorene (BFe) had been reported [17][18][19][20], up to now, there was not a systematic study of PBFe film electrodeposited by direct anodic oxidation of BFe and characterizations of corresponding polymers because the electropolymerization of BFe was more difficult in neutral solvent due to the electro-withdrawing group substitution (bromine) on the fluorenyl unit, leading to higher oxidation potential compared with Fe monomer. For example, Triebe and coworkers [17] studied the redox behavior of 9,9-dibromofluorene in dimethylformamide and found their redox behaviors were affected significantly by electrocatalysis from reduction products of the starting compounds.…”

“…MacGowan and colleagues [18] studied the picosecond time scale competition between intersystem crossing and carbon-halogen bond homolysis resulting from 266-nm excitation of BFe in the nonpolar solvent cyclohexane. Goodman and coworkers [19] investigated the synthesis and characterization of fluorine end-labeled polystyrene with BFe as the initiator by atom transfer radical polymerization. Recently, the reductive homocoupling of BFe was catalyzed by Ru 3 (CO) 12 in refluxing xylene and bifluorenyls were obtained by Sridevi et al [20].…”

Polystyrene End‐Labeled with 2,7‐Dibromofluorene Synthesized Using an Adaptation of Reverse Atom Transfer Radical Polymerization

“…UV-vis spectroscopy of the polymer solution showed absorption bands red-shifted from those of molecular 2,7-dibromofluorene (Figure 2a), indicative of a polymer-bound aromatic chromophore. [30,31] Determination of the extent of incorporation using Beer-Lambert's Scheme 2. Adaptation of RATRP to produce polystyrene end-labeled with fluorenyl groups.…”