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New series of phthaloperinone dyes were synthesized by the condensation reaction between tetrachloro-phthalic anhydride, 2,3-naphthalene dicarboxylic anhydride and o-phenylenediamine, 1,8-diaminonaphthalene, 1,2-diaminoanthraquinone. These dyes absorb at around 370-490nm. It was found that introduction of naphthalene and anthraquinone moiety on the perinone system produces a large bathochromic shift of 100nm. The synthesized dye 7 containing anthraquinone moiety in perinone chromophoric system exhibited superior heat stability and bright color as yellow chromophore. New dye 7 have been investigated in terms of interacting with volatile organic compound(VOC) EtNH2. The sensing behaviour of the dye 7 toward EtNH2 was studied by UV-vis absorption spectroscopy. Sensing mechanism of dye 7 to EtNH2 was supported by theoretical calculations based on DFT method. Keywords

Molecules always show broad absorption band envelopes, and this results from the vibrational properties of bonds. The width of an absorption band can have an important influence on the color of a dye. A narrow band imparts a bright, spectrally pure color to the dye, whereas a broad band can give the same hue, but with a much duller appearance. Typically, half-band widths of cyanine dyes are about 25nm compared to value of over 50nm for typical merocyanine dyes. Thus, cyanine dyes are exceptionally bright. The factors influencing the width of an absorption band can be understood with reference to the Morse curves. The width of the absorption band depends on how closely the bond order of the molecules in the first excited state resembles that in the ground state. We have quantitatively evaluated the "molecular structure-absorption band shape" relationship of dye molecules by means of Pariser-Parr-Pople Molecular Orbital Method(PPP-MO).

Abstract:Two new D-π-A dyes were synthesized by the condensation reaction between active methyl and aromatic aldehyde and its biothiol sensing properties in DMSO/water were investigated by UV-vis spectroscopy. Upon addition of Hg 2+ , the solution of D-π-A dyes showed color change and the absorption band shows a formation of a dye-Hg 2+ coordination complex. These dyes exhibited high selectivity for Hg 2+ as compared with other cations. The dye-Hg 2+ could be recovered by adding glutathion(GSH). The absorption intensity of dye-Hg 2+ increased only by the addition of glutathione(GSH). The competition experiments revealed that no obvious interference was observed by performing the titration with the mixture of glutathione(GSH) and other amino acids.The results indicated that these D-π-A dyes were highly selective for glutathione(GSH) detection.

Abstract:The interaction between curcumin(1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) and ethylamines was studied in DMSO:H2O(5:1, v/v) using absorption and fluorescence measurements. The association constant, Kass, and the Stern-Volmer constants were calculated by the Benesi-Hildebrand and Stern-Volmer equation, respectively. Curcumin displayed marked UV-Vis absorption changes and highly responsive fluorescence quenching in the presence of ethylamine and the quenching ability was enhanced almost linearly with the concentration of ethylamines. The apparent Stern-Volmer constant measured for the ethylamine-curcumin system was about 1000-fold greater than that of the triethylamine-curcumin system, indicating considerably greater quenching efficiency of ethylamines.