Fluorene derived polymers

The photoconductive properties of the fluorene-derived polymers 19, 23, and 24 were studied by the single-layer photocells in the configuration of ITO/Pt polyyne/Al. These polymers show moderate photoconductivity. A PCQE of 0.01 % was estimated in these cases, which does not vary much with variation of the central fluorene ring.26,30 Likewise, polymer 44 was also shown to be a photoconducting material in a similar architecture with a PCQE of 0.01 % in the forward bias mode. 

As demonstrated in previous sections, the carbazole unit was introduced as a pendant group or as a chain member in major classes of EL polymers such as PPVs (95-105,141,177, 190) and PFs (62, 63, 242-245). A variety of 2,7-carbazole-derived polymers with different conjugated units, such as 2-alkoxy- and 2,5-dialkoxy-l,4-phenylene (549) and l,l -binaphtha-lene-6,6 -diyl (550 [658]), 2,5-pyridine (551), 2,7-fluorene (245 [345,346]), 2,5 -bithiophene (554 [345]), 5,8-quinoxaline (552), quinquethiophene-SjS -dioxide (450 [550]), 2,5-thiophene (553), 2,5-furan (555), and acetylene (556 [659]) were reported by Leclerc and coworkers... 

The materials studied for 2PA properties involve a number of types of conjugated structures with donor and acceptor groups from stryl to cyanine dyes. Our group is particularly interested in conjugated fluorene derivatives. Fluorene derivatives have been used in conducting polymers, more recently in... 

Polyaromatic phosphine oxide, (VI), and diamines, (Vll), were prepared by Towns [4] and coupled with fluorene derivatives, (Vlll), to produce the corresponding polyaromatic polymers. 

Nemoto, N. Yamaguchi, T. Ozawa, Y. Nigorikawa, M. Yanai, Y. Nagase, V., Synthesis and Thermal Characterization of Novel Fluorene-Based Polysilox-ane Derivatives. Polym. Bull. 2008, 61,165-175. 

The unhindered release of fluorene derivatives from a fully solvated peptide-polymer matrix results in a characteristic bell-shaped elution profile (20) Figure 2a). Syntheses that exhibit such profiles throughout their assembly are generally of an excellent crude quality. In the case of difficult peptide sequences, the slowing of reaction kinetics at the onset of aggregation is readily observed as a broadening of the release of fluorene derivatives from the reaction matrix Figure 2b). In severe instances, the monitored release of... 

Oxidation of some fluorene derivatives, such as 1-hydrofluorene or fluorene-1-carboxylic acid, does not produce polymer films. Two explanations have been proposed [186]. First, strong electron withdrawing groups such as carboxylic acid may destablize the fluorene radical cation and promote reactions with the solvent or anions. Conversely, donor substituents such as hydroxyl groups may stabilize the fluorene cation radical intermediates enough so that the radicals may diffuse away... 

Recently, polyimines include the synthesis of long alkoxy (Cg-Cig) side chain derivatives [188,189], which are presumably soluble to some extent in organic solvents and derivatives containing fluorene cardo unit [190]. Trifluoromethyl groups [191] in the polymer backbone provide solubility in organic solvents. Studies of the electrical conductivity of doped conjugated aromatic polyimines and alkoxy derivatives have been reported [188], and the values are in the range of 10 to 10 S/ cm. 

In the absence of capping ligands, polymeric alkynylmercury derivatives can be readily prepared. Polymer 57 is formed by reaction of HgC with 9,9-bis(4-ethynylphenyl)-fluorene in a basic methanolic solution. This polymer, whose average molecular weight (/I7W) is only 8,900, shows a strong triplet emission of the organic chromophore enhanced by the presence of the mercury heavy atom.69... 

Q. Peng, Z. Lu, Y. Huang, M. Xie, D. Xiao, and D. Zou, Novel light-emitting polymers derived from fluorene and maleimide, J. Mater. Chem., 13 1570-1574, 2003. 

Intensive effort has been devoted to the optimization of CCP structures for improved fluorescence output of CCP-based FRET assays. The inherent optoelectronic properties of CCPs make PET one of the most detrimental processes for FRET. Before considering the parameters in the Forster equation, it is of primary concern to reduce the probability of PET. As the competition between FRET and PET is mainly determined by the energy level alignment between donor and acceptor, it can be minimized by careful choice of CCP and C. A series of cationic poly(fluorene-co-phenylene) (PFP) derivatives (IBr, 9, 10 and 11, chemical structures in Scheme 8) was synthesized to fine-tune the donor/acceptor energy levels for improved FRET [70]. FI or Tex Red (TR) labeled ssDNAg (5 -ATC TTG ACT ATG TGG GTG CT-3 ) were chosen as the energy acceptor. The emission spectra of IBr, 9, 10 and 11 are similar in shape with emission maxima at 415, 410, 414 and 410 nm, respectively. The overlap between the emission of these polymers and the absorption of FI or TR is thus similar. Their electrochemical properties were determined by cyclic voltammetry experiments. The calculated HOMO and LUMO... 

Research Focus Synthesis of poly( fluorene-co-triphenylamine) derivatives as hole transport polymers. 

A very efficient green-light-emitting fluorene copolymer 582 was synthesized by Shim and coworkers (03MM4288). Also, thieno[2,3-lj]thiophene derivatives can be used to synthesize new semiconductors (05JA1078) the polymer showed Amax at 467- 72 nm. 

Green electroluminescence is also achieved from the well-defined alternating copolymer 12 with a repeating unit made up of ter-(2,7-fluorene) and 2, 5-silole.29 With its neat film as the emissive layer, the EL device shows a maximum //Kr of 0.47%, but the device performance can be largely improved to a maximum //Ki. of 1.99% when using a copolymer/PF8 blend film as the emissive layer. Copolymer 14 derived from 2,7-dibenzosilole and 2,1,3-benzothiadiazole is also an excellent green EL polymer.26 A maximum 7el of 3.81% can be realized in EL devices. 

The nature of the DNA adduct remains to be determined. However the spectrum of the isolated DNA is similar to that of the DNA adduct formed when 2-aminodifluorenylamine is oxidized by a peroxidase-H202 reaction mixture. Furthermore a similar DNA adduct is formed when DNA is added at a time when the blue imino derivative is maximal. Furthermore in the presence of DNA much less extractable azofluorene, aminodif luoreny lamine or polymer was formed suggesting that DNA reacts with the amino-fluorene cation radical and 2-iminodifluorenylamine. 

Another interesting light-emitting moiety is a fluorene molecule. Polyflu-orene derivatives have extremely high luminescence efficiencies in solution, which are largely maintained in the polymer films [91]. As a result, polyflu-... 

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