Dissolved organic matter in water of Daugava river

Synthesis of New Solvatochromic Dyes by Reduction of BenzanthroneAzomethinesI.D.Ivanova 1 , N.V.Orlova 1 , E.M.Kirilova 21 Faculty of Chemistry, University of Latvia, 48 Valdemara str., LV-1013, Riga (Latvia);2 Chemistry Department, Daugavpils University, 13 Vienibas str., LV-5401, Daugavpils(Latvia).Many derivatives of benzo[de]anthracene-7-one exhibit strong emission, which accountsfor their use in practice as active lasing media and fluorescent probes for investigation ofbiological objects. In present work a number of new derivatives of 3-aminobenzanthronewere synthesized. In summary, ten new dyes were synthesized in good yields (80-87%)via the reduction of corresponding azomethine derivative by sodium borohydride in DMFsolutions.The structure of obtained compounds was confirmed by NMR and FT-IR spectroscopyand mass spectrometry. Single-crystal structures of obtained dyes were determined by X-ray diffraction studies. In addition, thermal stability of the synthesized chromophores hasbeen undertaken using TG–DTA. The influence of solvents with various polarities uponabsorption and emission spectra was investigated. The absorption and luminescent spectraof the novel compounds in several solvents of different polarity were investigated. Thesynthesized dyes absorb at 520-580 nm with high extinction coefficients, have relativelylarge Stokes’ shifts (about 100 nm), and emit at 650-720 nm showing both absorption andfluorescence solvatochromism similarly to studied earlier 3-amino derivatives ofbenzanthrone [1,2]. The results indicated that these dyes were strongly dependent onsolvents and show generally bathochromic shifts as the polarity of solvents was increased.These characteristics of obtained dyes demonstrate their potential as biomedical probesfor proteins, lipids and cells.1. Kirilova, E. M; Kalnina, I; Kirilov, G. K; Meirovics, I. J. Fluoresc 2008, 18 (3-4), 645-648.2. Gorbenko, G.; Trusova, V.; Kirilova, E.; Kirilov, G.; Kalnina, I.; Vasilev, A.; Kaloyanova, S.;Deligeorgiev, T. Chem. Phys. Lett, 2010, 495, 275–279.- 10 -