Rhodamine dyes

A high concentration of the fluorescent dye itself in a solvent or matrix causes concentration quenching. Rhodamine dyes exhibit appreciable concentration quenching above 1.0%. Yellow dyes, on the other hand, can be carried to 5 or even 10% in a suitable matrix before an excessive dulling effect, characteristic of this type of quenching, occurs. Dimerization of some dyes, particularly those with ionic charges on the molecules, can produce nonfluorescent species. 

Additional Chromophores. Other types of dyes that have been studied as chromophores in dye developers include rhodamine dyes, azamethine dyes, indophenol dyes, and naphthazarin dyes (21). Cyanine dyes, although not generally stable enough for use as image dyes, have also been incorporated in dye developers (31). 

Figure 1. Catalog page of meta-autunite, including 3-D perspective excitation-emission plot, maximum excitation and emission spectra, and rhodamine dye equivalencies.

The rhodamine B-bound complex of Ir1 (387) shows only minor alterations in the absorption spectrum of bound rhodamine B as opposed to free dye however, its fluorescence is strongly quenched.626 Fluorescence is intense when the rhodamine dye is attached to an Ir111 center. The authors conclude that the excited-state quenching mechanism is via electron transfer. 

Aarthi, T. and Madras, G. (2007) Photocatalytic degradation of rhodamine dyes with nano-Ti02. Industrial and Engineering Chemistry Research, 46, 7-14. 

Walsh RJ, Reinot T, Hayes JM et al (2002) Nonphotochemical hole burning spectroscopy of a mitochondrial selective rhodamine dye molecule in normal and cancerous ovarian surface epithelial cells. J Lumin 98 115-121... 

Nestmann ER, Douglas GR, Matula TI, Grant CE, Kowbel DJ (1979) Mutagenic activity of rhodamine dyes and their impurities as detected by mutation induction in Salmonella and DNA damage in Chinese hamster ovary cells. Cancer Res 39 4412-4417... 

Slow-response probes (response times greater than milliseconds) cationic car-bocyanine and rhodamine dyes and anionic oxonol dyes... 

Nguyen, T. and Francis, M. B. (2003). Practical synthetic route to functionalized rhodamine dyes. Org. Lett. J, 3245-3248. 

Organic fluorescent dyes with the appropriate spectral properties also can be paired with lanthanide chelates in FRET systems. For instance, many rhodamine dyes and the cyanine dye Cy5 have ideal excitation wavelengths for receiving energy from a nearby europium chelate. The LeadSeeker assay system from GE Healthcare incorporates various Cy5-labeled antibodies for developing specific analyte assays. In addition, if using a terbium chelate as the donor, then a Cy3 fluorescent dye can be used in assays as the acceptor. 

Fig. 3 (a) Normalized excitation and emission spectra of 5-(and-6)-carboxy-fluorescein, succini-midyl ester, rhodamine 6G (R6G), and 6-carboxy-X-rhodamine dyes in pH 7.4 phosphate buffer, (b) Confocal fluorescence image of a mixture of five types of microsphere-DDSN complexes under 488-nm Argon-ion laser excitation. Reproduced with permission from Ref. [12]... 

Rhodamine dyes were used as test compounds for the detection of the positive-ion mode while FD C dyes were detected in the negative-ion mode. Stationary phases for... 

Butterfly-type folding has also been discussed in the context of rhodamine dyes adsorbed on surfaces/53 In this case, too, nonexponential fluorescence decays are observed. A comparison of the consequences of the different reaction mechanisms with respect to free volume sensing is given in Section 5.4. 

Figure 5.12. Various possibilities of introducing a fast TICT channel into a Rhodamine dye like Rhodamine B (see text).

Figure 5.16. Various structures of triphenylmethane and Rhodamine dyes.

As shown above with the example of Rhodamine dyes, TICT channels can be introduced into most other dye systems giving a large flexibility in choosing absorption and emission wavelengths to adapt to given conditions of the material to be investigated. 

M. Vogel, W. Rettig, R. Sens, and K. H. Drexhage, Structural relaxation of rhodamine dyes with different N-substitution patterns A study of fluorescence decay times and quantum yields. Chem. Phys. Lett. 147,452-460 (1988). 

C. J. Tredwell and A. D. Osborne, Viscosity dependent internal conversion in the rhodamine dye, fast acid violet 2R, J. Chem. Soc. Faraday Trans. II 76, 1627 (1980). 

Figure 5.25 — Flow-through ion-selective optrode based on a multilayer lipidic membrane prepared by the Langmuir-Blodgett method. (A) Cross-sectional view of the composite six-layer membrane (four layers of arachidic acid/ valinomycin covered by an arachidic acid and rhodamine dye bilayer). (B) Optical arrangement integrated with the sensor, which is connected to a flow system. LS light source Ml and M2 excitation and emission monochromator, respectively FI and F2 primary filters M mirror LB lipid-sensitive membrane in a glass platelet FC flow-cell A amplifier D display P peristaltic pump. (Reproduced from [107] with permission of the Royal Society of Chemistry).

Anchoring of rhodamine B sulfonylchloride 2. Anchoring the rhodamine dye was carried out under similar conditions as in the preceding paragraph. A suspension of 3-aminopropylsilyl-MCM-41 and 2 in 40 mL dichloromethane was precooled and after 1.5 h an excess of the catalyst pyridine was added. The reaction was finished after 20 h of stirring and the recovered solid extensively washed and subjected to a Soxhlet treatment. 

Figure 3. Nitrogen adsorption measurement a) calcined MCM-41, b) outer surface silylated, c) APTES-functionalized material and d) grafted rhodamine dye.

Figure 4. Diffuse reflectance UV/vis spectra of MCM-41 a) with adsorbed rhodamine dye (0.0075-mmol/g MCM-41), b) with covalently grafted rhodamine dye (0.01 m mol/g MCM-41 0.5 mmol APTES/g MCM-41) compared to rhodamine B sulfonylchloride c) in ethanol and d) in water.

UV/vis reflectance spectroscopy. The main absorption band of the anchored rhodamine dye at 553 nm or of the azo dye at 441 nm, determined by the UV/vis reflectance spectroscopy, represents a blue-shift in comparison to spectra in aqueuos solution. In water (pH 7) the azo dye provides a band at 468 nm and the rhodamine dye a main absorption band at 565 nm. 

At low concentrations of the anchored rhodamine dye, the samples exhibit a strong fluorescence, which indicates the presence of individual, free chromophore moieties. To avoid... 

Previous studies on paraffins, rhodamine dyes, and l,3-bis(N-carbozoyl) propane excimers have concluded that there is a relationship between km and polymer viscosity and free volume [103-105], Indeed, this dependence has been investigated in the context of decreasing free volume during methyl methacrylate polymerization [83,84], It has been shown that the nonradiative decay processes follow an exponential relationship with polymer free volume (vf), in which kra reduces as free volume is decreased [see Eq. (5)]. Here, k. represents the intrinsic rate of molecular nonradiative relaxation, v0 is the van der Waals volume of the probe molecule, and b is a constant that is particular to the probe species. Clearly, the experimentally observed changes in both emission intensity and lifetime for/ac-ClRe(CO)3(4,7-Ph2-phen) in the TMPTA/PMMA thin film are entirely consistent with this rationale. 

Cyclized di- or triarylmethine dyes are also known as acridine, xanthene, or thioxanthene dyes. Rhodamine GG (33), C.I. Basic Red 1, 45160 [989-38-8], is of the most interest for the paper industry. Rhodamine dyes dye paper in strongly fluorescent red shades. 

Non-contact temperature measurement inside microfluidic channels was achieved by using fluorescence quenching of a rhodamine dye. The intensity of the dye fluorescence is temperature-sensitive in a range temperature of 5-95°C [795], Another on-chip temperature measurement method was achieved by measuring... 

Eytan GD, Regev R, Oren G, et al. Efficiency of P-glycoprotein-mediated exclusion of rhodamine dyes from multidrug-resistant cells is determined by their passive transmembrane movement rate. Eur J Biochem 1997 248(1) 104—112. 

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