Syntheses And Characterization Of Rhodamine Derivatives

In this thesis, 5 series of rhodamine derivatives were designed and synthesized including bottom ring modified, N-stabilized, asymmetrical, consisted of double fluorescence groups and ion binding rhodamine derivatives in order to improve the fluorescence intensity and quantum yield, longer-wavelengths, pH-sensitive range, the large Stokes shift and ion binding specificity. The fluorescence properities of the obtained compounds were investigated by UV-vis spectra and fluorescence spectra. The relationship between their structures and photophysical properties were summarized. The details were described below:Nitro-rhodamine and amino-rhodamine were synthesized. A series of 5 (6)-halo-rhodamine were obtain from amino-rhodamine through diazotization, Sandmeyer reaction. Synthesis and isolation of mono and full substituted chlororhodamines, full-fluoro substituted rhodamines and rhosamine without carboxyl group on the bottom ring were investigated in this paper. Comparing with rhodamine B, although the fluorescence intensity of aminorhodamine was improved, this property of nitrorhodamine had weakened,λex andλem were red shift. The introduction of halo element to rhodamine structure enlargedλmax-ex andλmax-em As the number of halo-atom increasing,λmax-ex andλmax-em were red shift, Stokes shift had decreased. Carboxyl group on the bottom ring had almost no influence to fluorescence properties.Five N stabilized rhodamine derivatives at xanthene were synthesized and their fluorescence properties were tested by UV-vis spectra and fluorescence spectra. It was found thatλmax-ex andλmax-em were red shift more than 20nm from visible light area to IR area. N-stablization increased in co-planar and rigidity which lead to the enlargement of Stokes shift and intensity of fluorescence intensity.Asymmetric rhodamines bdc-1～bdc-11 was designed and synthesized.the overlap betweenλmax-ex andλmax-em for these compounds decreased, at same time Stokes shift increased. The greater asymmetric degree, the larger of the Stokes shift. Theλmax-em of bdc-4 and bdc-5 were red shift. Bdc-10 showed different absorption and emission wavelengths in acid and base solution.Rhodamine and fluorescein were linked to obtain double fluorescence group by chemical bond. The fluorescence spectrum of the compounds showed obvious variety in different pH solution. Rhodamine-calix[4]arene was linked together by amide group. Its fluorescence and metal ion bind ability were tested. The UV-vis absorption changed when the addition of this compound into the methanolic solution containing Cu2+ and Zn2+.