Fluorene characterized

SUMMARY OF NICI REACTIONS OF FLUORENE CHARACTERIZED BY FTMS... 

Grifoll M, M Casellas, JM Bayona, AM Solanas (1992) Isolation and characterization of a fluorene-degrading bacterium identification of ring oxidation and ring fission products. Appl Environ Microbiol 58 2910-2917. 

Figure 7.23 shows the prototype diazobenzo[Z ]fluorene-based natural products kinamycin A and prekinamycin. The kinamycin A-D family were first isolated from Streptomyces murayamaensis, but the structures were incorrectly characterized as having a cyanobenzo[Z ]carbazole ring. Since the initial discovery of the kinamycins, many new analogues have been discovered from natural sources.88-92... 

J. Cornil, I. Gueli, A. Dkhissi, J.C. Sancho-Garcia, E. Hennebicq, J.P. Calbert, V. Lemaur, D. Beljonne, and J.L. Bredas, Electronic and optical properties of polyfluorene and fluorene-based copolymers a quantum-chemical characterization, J. Chem. Phys., 118 6615-6623, 2003. 

Y. Fu, J. Li, S. Yan, and Z. Bo, High molecular weight dendronized poly(fluorene)s with peripheral carbazole groups synthesis, characterization, and properties, Macromolecules, 37 6395-6400, 2004. 

B. Liu, W.-L. Yu, Y.-H. Lai, and W. Huang, Synthesis, characterization, and structure-property relationship of novel fluorene-thiophene-based conjugated copolymers, Macromolecules, 33 8945-8952, 2000. 

E. Lim, B. Jung, and H. Shim, Synthesis and characterization of a new light-emitting fluorene-thieno[3,2-6]thiophene-based conjugated copolymer, Macromolecules, 36 4288-4293, 2003. 

Trimpin, S. Grimsdale, A.C. Rader, H.J. Mullen, K. Characterization of an Insoluble Poly(9,9-Diphenyl-2,7-Fluorene) by Solvent-Free Sample Preparation for MALDI-TOF-MS. Anal. Chem. 2002, 74, 3777-3782. 

One case of n—5 —n delocalization was demonstrated by Stevenson et al. (2006). The potassinm anion-radical salt of l-(9-methyl-9H-fluoren-9-yl)-4-methyl benzyl is characterized by the delocalization of an nnpaired electron within the fluorenyl moiety only. Its ESR spectrnm completely coincides with the spectrnm of the potassium anion-radical salt of the 9,9-dimethyl fluorene anion-radical in THE However, the cesium anion-radical salt of the fluorenyl methylbenzyl derivative produces the ESR spectrum corresponding to the placement of this cation between the fluorenyl and methylbenzyl moiety. The conditions of n—s—n delocalization appear An unpaired electron spends its time within both fluorenyl and methylbenzyl fragments. The situation is explained in Scheme 3.54. 

As evidence that a monolithiated compound can form an equilibrium with the corresponding dilithiated compound involved, the group of Linti and coworkers crystallograph-ically examined 9,9-dilithiofluorene (45). The molecule is formed when 9-lithiofluorene (44) is dissolved in a THF/benzene mixture by an intermolecular deprotonation yielding 45 and fluorene (43). In spite of the poor solubility of compound 45, which does not allow a characterization by NMR methods, the equilibrium is still on the side of the monolithiated compound (Scheme 16). The crystal structure of compound 45 has been reported and reveals a coordination polymer in the solid state (Figure 13). 

The high reactivity of the C=S bond toward diazo dipoles was also helpful in the characterization of thiopivaldehyde, a monomeric thioaldehyde persistent in inert organic solvents for 16 h at 20 °C. This thioaldehyde underwent ready cycloaddition with ethyl diazoacetate (210). Similarly, the diazocumulene 9-(diazomethylene)fluorene could be generated by diazotization of 9-(aminomethy-lene) fluorene and was trapped by the cycloaddition with thiobenzophenone (211). 

Compounds om.4 and om.5 have the same metal center as om.l, but longer conjugated linkers, which also incorporate fluorene units, and they have terminal donor groups. 2PA spectra of these molecules are characterized by... 

The photochemical stabihty of the molecules is characterized by the quantum yield of photodecomposition, (P = N/Q [69], where N and Q are the numbers of decomposed molecifles and absorbed photons, respectively. The photochemical properties of the fluorene derivatives were investigated in different organic solvents (hexane, CH2CI2, ACN, and polyTHF) at room temperature by the absorption and fluorescence methods and comprehensively described [70-72]. These methods are based on measurements of the temporal changes in the steady-state absorption and fluorescence spectra during irradiation. For the absorption method, the quantum yield of the photodecomposition under one-photon excitation, c >ipa, can be obtained by the equation [73] ... 

Triphenylmethane derivatives, rhodamines, and nitro derivatives of 9-dicyanomethylene fluorene are characterized by -type photoconductivity. 

The solvolysis reactions of 9-substituted fluorenes have been examined in studies to characterize the effect of the delocalized 12-7T cyclic array of electrons... 

As with crystalline organic semiconductors, there are only few systematic and quantitative studies of bias stress in polymeric TFTs. For example, it is still unclear whether in all polymers a positive VG leads to positive Vj shifts [7, 18]. Here we will concentrate on negative AVT after application of a negative Vg, which is nearly universally observed in p-type devices with a number of semiconductor-dielectric combinations. In the next section of this chapter we will focus on studies of poly-fluorene and polythiophene TFTs, because these are the polymer devices for which bias stress has been most thoroughly characterized in recent years. 

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