Fluorescein structure

P.R.90 is derived from the fluorescein structure (147). Fluorescein is a yellow dye with intensely green fluorescence which was discovered by A.v.Bayer in 1871. It is prepared by heating resorcin and phthalic anhydride with zinc chloride or concentrated sulfuric acid ... 

Fluorescein structural formula and molecular model. This strongly fluorescent dye has many applications. It is widely used to study retinal circulation and various diseases involving the retina. The technique is known as fluoi escein angiography. Fluorescein can be bound to DNA and other proteins and its fluorescence used as a probe of these molecules and their interactions. Fluorescein is also used for water tracing to provide information on the contamination of underground wells. In addition, it has been used as a laser dye. 

Anthoni U, Christophersen C, Nielsen P, Puschl A, Schaumburg K. Structure of red and orange fluorescein. Structural Chem 1995 3 161-5. 

Song A-M, Zhang J-H, Zhang M-H et al (2000) Spectral properties and structure of fluorescein and its alkyl derivatives in micelles. Colloids Surf A 167 253-262... 

Fig. 6 General structure of xanthene dyes containing fluorescein, eosin, and rhodamine...

One of the interesting features in the structure-photophysical property relationship of fluorescein is that the quantum yield of fluorescein increases under the basic condition. Therefore, many of fluorescein derivatives have been used as pH sensors to measure intracellular pH due to their pH-responding photophysical property [53]. Although fluorescein itself is slightly fluorescent in alcoholic solutions, the addition of alkali (pH > 8) to the fluorescein solution produces the very intense fluorescent alkali salt. The salt form of fluorescein... 

Fig. 8 Structure-photophysical properties relationship of fluorescein derivatives. Measured in 0.1 N NaOH(aq). bOxidation potential of corresponding benzene moiety, obtained in acetonitrile containing 0.1 M TBAP. °HOMO energy level of the corresponding benzene moiety, calculated with B3LYP/6-31G(d)//B3LYP/6-31G(d) by Gaussian 98 W...

Fig. 9 Structure-photophysical properties relationship of benzannulated fluorescein derivatives...

Fig. 6.2. Chemical structures of fluorescein and some commonly used derivatives. The carboxylic acid groups are used for forming conjugates with other molecules.

Due to their longer wavelength fluorescence and photostability, rhodamine and its derivatives have often been employed for the labeling of probes tested in living cells. Like fluorescein, the chemical structure of rhodamine consists of an upper xanthene ring and a lower benzene ring. In this case, the xanthene ring is substituted... 

Fluorescein and its derivatives represent one of the most popular of all fluorescent labeling agents. Its fluorescent character is created by the presence of a multi-ring aromatic structure due to the planer nature of its upper, fused three-ring system (Figure 9.4). In its most elementary... 

Texas Red hydrazide is a derivative of Texas Red sulfonyl chloride made by reaction with hydrazine (Invitrogen). The result is a sulfonyl hydrazine group on the No. 5 carbon position of the lower-ring structure of sulforhodamine 101. The intense Texas Red fluorophore has a QY that is inherently higher than either the tetramethylrhodamine or Lissamine rhodamine B derivatives of the basic rhodamine molecule. Texas Red s luminescence is shifted maximally into the red region of the spectrum, and its emission peak only minimally overlaps with that of fluorescein. This makes derivatives of this fluorescent probe among the best choices of labels for use in double-staining techniques. 

The above findings are supported in the other studies of the inhibitory effects of flavonoids on iron-stimulated lipid peroxidation. Quercetin was found to be an inhibitor of iron-stimulated hepatic microsomal lipid peroxidation (/50 = 200 pmol I ) [134]. Flavonoids eriodictyol, luteolin, quercetin, and taxifolin inhibited ascorbate and ferrous ion-stimulated MDA formation and oxidative stress (measured by fluorescence of 2,7,-dichlorodihydro-fluorescein) in cultured retinal cells [135]. It should be mentioned that in recent work Heijnen et al. [136] revised the structure activity relationship for the protective effects of flavonoids against lipid peroxidation. 

Figure 5 shows two typical core-shell structures (a) contains a metal core and a dye doped silica shell [30, 32, 33, 78-85] and (b) has a dye doped silica core and a metal shell [31, 34]. There is a spacer between the core and the shell to maintain the distance between the fluorophores and the metal to avoid fluorescence quenching [30, 32, 33, 78-80, 83]. Usually, the spacer is a silica layer in this type of nanostructures. Various Ag and Au nanomaterials in different shapes have been used for fluorescence enhancement. Occasionally, Pt and Au-Ag alloys are selected as the metal. A few fluorophores have been studied in these two core-shell structures including Cy3 [30], cascade yellow [78], carboxyfluorescein [78], Ru(bpy)32+ [31, 34], R6G [34], fluorescein isothiocyanate [79], Rhodamine 800 [32, 33], Alexa Fluor 647 [32], NIR 797 [82], dansylamide [84], oxazin 725 [85], and Eu3+ complexes [33, 83]. 

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