Naphthalene fluorophore

The amine-reactive 5-(dimethylamino)naphthalene-l-sulfonyl (dansyl) chloride 28 [80] and related fluorophores [81, 82], as well as the 5-((2 aminoethyl)amino) naphthalene-1-sulfonic acid (EDANS) 29, are included in the naphthalene fluorophore family. Derivatives of the latter, such as compound 30, exhibit a Lm.ix/ Lem 336/520 nm, molar absorptivity (e) of 6.1 x 103 M-1 cm-1, and a fluorescent quantum yield of 0.27 in water [83], The use of EDANS is particularly interesting in FRET experiments [84, 85]. Furthermore, 4-amino-3,6-disulfonylnaphthalimides (e.g., Lucifer yellow 31), associated to a longer absorption (Lmax 428 nm) [86] are suitable polar tracers [87]. 

Calixarene-based compounds PCT-22 and PCT-23 (Figure 10.25) containing one or four appended naphthalenic fluorophores, respectively, exhibit outstanding fluorescence enhancements upon cation binding and are very selective for Na+ (see Box 10.2). 

In the case of PCT-23 (Figure 10.25) containing four appended naphthalenic fluorophores, similar photophysical effects induced by complexation of alkali and alkaline earth metal ions (i.e. red-shift of the absorption and the emission... 

Fig. 8.15 Cyclam dendrimer (ionophore) with 16 terminal naphthalene fluorophores (according to Balzani, Vogtle et at.)...

As an example of excitation energy transfer studied by time-resolved fluorescence, let us take again the case of the inclusion complex of the multichromophoric cyclodextrin CD-St with oxazine 725 described in Section 7.2.4.2 [15]. Figure 7.9 shows the fluorescence decay of CD-St the very first part of the decay is due to energy transfer [13] from the steroidic naphthalene fluorophores to oxazine 725. Data analysis led to an average decay time for transfer of about 25 ps, which is quite fast, as expected from the short average distance between donor and acceptor ( 9-10 A). 

J2.4 Nonradiative Energy Transfer Unique information concerning the conformational behavior of aqueous solutions of PAA bearing naphthyl (donor) and pyrenyl (acceptor) species has been derived from NRET measurements [120]. A plot of the ratio of pyrene to naphthalene emission intensity (/py//np) upon excitation of the naphthalene fluorophores at 290 nm as a function of pH is shown in Fig. 2.10. The... 

The dansyl derivative 9-azidononyl-5-(dimethylamino)naphthalene-l-sulfonate 35 was used by Yi and collaborators [91] as an azido-fluorescent label in a tandem method of sulfonium alkylation and click chemistry for the modification of biomolecules. Fluorescent labeling of a protein was successfully carried out after simple incubation of BSA with sulfonium salt 36 followed by azido-containing fluorophore 35, at room temperature. 

The same authors studied the CL of 4,4,-[oxalylbis(trifluoromethylsulfo-nyl)imino]to[4-methylmorphilinium trifluoromethane sulfonate] (METQ) with hydrogen peroxide and a fluorophor in the presence of a, p, y, and heptakis 2,6-di-O-methyl P-cyclodextrin [66], The fluorophors studied were rhodamine B (RH B), 8-aniline-l-naphthalene sulfonic acid (ANS), potassium 2-p-toluidinylnaph-thalene-6-sulfonate (TNS), and fluorescein. It was found that TNS, ANS, and fluorescein show CL intensity enhancement in all cyclodextrins, while the CL of rhodamine B is enhanced in a- and y-cyclodextrin and reduced in P-cyclodextrin medium. The enhancement factors were found in the range of 1.4 for rhodamine B in a-cyclodextrin and 300 for TNS in heptakis 2,6-di-O-methyl P-cyclodextrin. The authors conclude that this enhancement could be attributed to increases in reaction rate, excitation efficiency, and fluorescence efficiency of the emitting species. Inclusion of a reaction intermediate and fluorophore in the cyclodextrin cavity is proposed as one possible mechanism for the observed enhancement. 

In contrast to the -conjugated probe architecture utilizing an ICT process, the number of anion probes that rely on the fluorophore-spacer-receptor design and an active PET process is abundant [72], Again, anthracene and naphthalene... 

The width of a band in the absorption or emission spectrum of a fluorophore located in a particular microenvironment is a result of two effects homogeneous and inhomogeneous broadening. Homogeneous broadening is due to the existence of a continuous set of vibrational sublevels in each electronic state. Absorption and emission spectra of moderately large and rigid fluorophores in solution could therefore be almost structureless at room temperature. However, in some cases, many of the vibrational modes are not active, neither in absorption nor in emission, so that a dear vibrational structure is observed (e.g. naphthalene, pyrene). 

Fluorophores which have been used to study solvent relaxation processes in membranes include 2-(p-toluidinyl)naphthalene-6-sulfonate (TNS)/130,132,I33 I35) dansylated lipids, and drugs/128,136)... 

While no spectroscopic evidence of a ground-state complex between anthracene and carbon tetrachloride, naphthalene or 1,2-benzanthracene and carbon tetrabromide has been found, Nemzek and Ware [7] were unable to explain their steady-state fluorescence quenching measurements with the parameters deduced from the determination of the time-dependent rate coefficients unless a ground-state complex was present. This cannot be regarded as a satisfactory and consistent analysis because the time-dependent rate coefficient would be modified by the presence of the initial distribution of quencher and fluorophor in the ground state. 

Balzani, Vogde et al. demonstrated for dendritic cyclam compounds that signalling units are dendritically amplified by increasing the number of peripheral fluorophores. Opportunities for these PET sensor systems exist in the combination of selective coordination sites with the dendritic architecture. The mechanism resembles that described above, but can be influenced by the introduction of dendritic units of different generations into the sensor system. The distance between the terminal naphthalene groups of the dendron and the receptor (ion as guest in the cyclam core) is of crucial importance for electron transfer (ET) (Fig. 8.15) [53],... 

Wtirthner, F., Ahmed, S., Thalacker, C. and Debaerdemaeker, T. (2002) Core-substituted naphthalene bisimides New fluorophores with tunable emission wavelength for FRET studies. Chemistry-A European Journal, 8, 4742-50. 

All data obtained with Tecan Ultra Evolution MTP reader. The following excitation and emission wavelengths were used EDANS and AMC 350 and 500 nm RhllO 485 and 535 nm TAMRA 535 and 595 nm PT14 405 and 450 nm. 4 = primary cleavage site confirmed by MS. AMC = aminomethylcoumarin. RhllO = rhodamine 110. yE = glutamic acid attached to RhllO via its carbonic acid in side chain. EDANS = fluorophore 5-[(2-aminoethyl)amino]naphthalene-l-sulphonic acid. DABCYL = 4-(4-dimethylaminophenylazo)benzoic acid quencher. BTN = biotin. PT14 = acridone-based fluorescence lifetime label. 

Current methods of detection for CAs in biological fluids (urine, plasma, and serum) involve chromatographic separation coupled to either electrochemical 119,120) or optical 121) techniques. However, most optical methods rely purely on the native fluorescence of CAs (lex 280 nm, lem 310 nm) 122), which have small Stokes shifts and suffer from signal losses due to reabsorption others involve pre- or postcoliunn derivatization with various fluorophores, such as naphthalene-2,3-dicarboxaldehyde 123), 1,2-diphenylethylenediamine 124,125), or fluorescamine 126). These methods all require significant time for separation using expensive instrumentation and thus are not feasible for rapid CA detection. 

Organic dye materials represent the largest and best characterized class of probes used in all manner of fluorescent analysis. As an overall class, these dyes are used in almost all areas of biotechnology, including biosensing, cellular imaging, clinical immunofluorescence, and in DNA/protein microarrays (42-45). Several major structural classes of organic fluorophore span the UV-to-near-IR spectrum see Fig. 4. UV dyes are typically pyrene-based, naphthalene-based, and coumarin-based structures, whereas the Vis/near-IR dyes include a variety of... 

The binding of fluorophores 6-(4-toluidino)naphthalene-2-sulfonate (TNS) and 6-(4-ZerZ-butylanilino)naphthalene-2-sulfonate (BNS) by bis(cyclodextrin)s has been studied by Sikorski and Petter [10]. The spacer length between the... 

An example of this technology is the HIV protease assay shown in Fig. 9, which was published by Wang and co-workers [67]. The peptide substrate is labeled at the amino terminus with EDANS (5-((2 -aminoethyl)amino)naphthalene-l-sulfonic acid) as a donor fluorophore and at the carboxyl terminus with DABCYL (4-((4 -(di-methylamino)phenyl)azo)benzoic acid) as the acceptor chromophore. In the intact peptide, fluorescence resonance energy transfer (FRET) from EDANS to DABCYL results in quenching of the EDANS fluorescence. On cleavage of the peptide by HIV protease, the fluorescence of EDANS is restored. 

A set of fluorophores derived from naphthalene, phenanthrene, pyrene, phenazine and fluorene have been conjugated to the 5 -ends of DNA and RNA to compare their physico-chemical properties. Decreasing the Ji-electron density led to an enhancement in thermal stability, attributable to more favourable Jt-Ji interactions. Stability is further enhanced by using nitrated fluorophores. Fluorescent labelling of ODNs using oxyamino modified fluorescein has been reported by the incorporation into DNA of aldehyde functions. The aldehyde function was attached either at the 5 -end via a phosphate linker or internally via 8-mercaptobutanal. Reduction of the resulting oxime was not necessary. 

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