Organic dyes based on fluorene and its derivatives

Conjugated compounds in supramolecular informational systems: A review

“…Thus, for exam ple, in [245,252] it was shown that, by means of vari ation of the concentrations of dye, polymer, and stearic acid, one can directly form molecular aggre gates of various structure. New approach for modeling of the excimer formation in mixed monolayers of polymethine dyes, that considers alteration of partial positive and negative charges characteristic for these compounds described in [253] and change of sign of charge of the participants of polymethine chain of the dye to the opposite one upon absorbance of quantum of light [128,254], proposed in [252] also deserves attention. The only drawback of the model created by the authors lies in the fact that it originates from the assumption that there is an initial mutual position of dye molecules in the monolayer in which like charged parts of the conjugation are located right opposite to each other, which would be energetically disadvanta geous.…”

Symmetric anionic polymethine dyes derived from bis(2,2,3,3,4,4,5,5-octafluoropentyl) 4,5-dinitro-9H-fluorene-2,7-disulfonate: synthesis and spectral properties

“…1,2 We have demonstrated 3-5 that em ployement of fluorene derivatives as such groups allows obtaining of deeply colored anionic dyes. Fluorene based polymethines containing the groups SO 2 OCH 2 (CF 2 ) 3 CHF 2 have been described. 4 Introduction of such electron with drawing groups into position 2 and 7 of the fluorene core makes the methylene group somewhat more active than that in unsubstituted fluorene.…”

Electrochemical and energetic characteristics of new dye-sensitizers for photovoltaic cells

“…[16][17][18] According to a recent study, 19 that these nitroaromatic dyes will adsorb well on the surface of titania. Adding strong electron-withdrawing substituents, like nitro groups, will enhance the resistance towards oxidation and make the dyes more stable.…”

“…21. The former dyes relate to the anionic type [16][17][18]20 and the latter onesto the intraionic merocyanines. 22 All PDs 1-6 reveal multiple light absorption bands 18,20,21 while the \classical" PDs show only a single band.…”

“…23 Multiple bands are due to various types of electron transfer involving different energy levels of the nitro groups participating in the general -conjugation system. [16][17][18]20 A variable length of the polymethine chain of all the dyes is a strong structural factor for both types of PD, and lengthening of this chain is seen 23 as the main tool to synthesize new useful deeply colored dyes.…”