Xanthene Ring Research Articles

N-[9-(2-Ethoxycarbonylphenyl)-6-(ethylamino)-2,7-dimethyl-3-xanthenylidene]ethylammonium Iodide Monohydrate

The xanthene moiety in the title compound, C28H31N2O3+.I−.H2O, is planar, with the attached phenyl ring twisted by −78.8 (6)° from the molecular plane. Of the two ethylamino groups one is coplanar and the other makes a dihedral angle of 152.1 (5)° with the xanthene ring system. The positive charge of the cation is delocalized and both N—C(sp2) bonds show double-bond character.

X-ray crystal structure analysis and atomic charges of color former and developer: 3. Color formers

The crystal and molecular structures of four color formers of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3H),9′[9H]xanthen]-3-one C 34H 32N 2O 3 ( 1), 2-anilino-3′-methyl-6′-N-ethyl-N-(4-methylphenyl)aminospiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one C 36H 30N 2O 3 ( 2), 2′-anilino-3′-methyl-6′-dibutylaminospiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one C 31H 28N 2O 3 ( 3) and 2′( o-chloroanilino)-6′-di-n-butylaminospiro[isobenzofuran-1(3H),(9′-[9H]xanthene]-3-one C 35H 35N 2O 3Cl ( 4) have been determined by single-crystal X-ray diffraction analysis. Atom–atom nonbonded potential energy calculations and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 4 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.7(4)–89.9(1)°) to the xanthene rings. The bond lengths C6–O2 are apparently extended from the normal C(sp 3)–O (lactone) length. Atomic net charges around spirocarbon C6 and toward N1 to C6 indicate a weak alternating system in colorless form. As the xanthene ring has a planar geometry, π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring by introducing H + at the C6 position. © 1997 Elsevier Science B.V.

Intercalation Characteristics of Rhodamine 6G in Fluor-Taeniolite: Orientation in the Gallery

AbstractThe orientation of rhodamine 6G (R6G) in the 22-Å basal-spaced complex with Li-fluor-taeniolite has been studied using X-raypowder diffraction, 1-dimensional Fourier analysis, polarized infrared (IR) spectroscopy, carbon analysis and thermal analysis. The R6G was adsorbed by cation exchange in aqueous solution. In the range of 0.086 to 0.46 molar ratio of R6G to taeniolite, the basal spacings of the complex were nearly constant at 21.7 to 22.2 Å. From X-raydiffraction (XRD) data, it was confirmed that R6G in the complex orients with its longest xanthene ring axis perpendicular to the ab plane of the host. The pleochroism of IR absorption bands at 1331, 1517, 1537 and 1621 cm−1 supports the vertical orientation. The wide stability range of the vertical configuration is consistent with the strong coulombic force between the highly negatively charged silicate layer of the host [cation exchange capacity (CEC) = 157 ± 9 meq/100 g] and the positively charged nitrogen bonded to both sides of the R6G xanthene ring.

Direct observation of rhodamine dimer structures in water

Self-association of rhodamine B, rhodamine 6G, and their mixture in aqueous solution has been studied by two-dimensional proton-proton nuclear Overhauser effect spectroscopy in the laboratory (NOESY) and rotating frames (ROESY). The strength of the observed cross-peaks between protons that are distant in the rhodamine monomer demonstrates intermolecular proximity between homodimers of rhodamine B and rhodamine 6G, and between heterodimers of rhodamine B and rhodamine 6G. It is shown that stacking of the xanthene rings occurs in all homo- and heterodimer interactions.

X-ray crystal structure analysis and atomic charges of color former and developer: 2. Color formers

The crystal and molecular structures of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one ( 1), 2′-amino-6′-( N-cyclohexyl- N-methylamino)-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one ( 2) and 2′-(2-chlorophenyl)amino-6′-dibutylaminospiro[isobenzofuran-1(3 H), 9′[9 H]xanthen-3-one ( 3) have been determined by single-crystal X-ray diffraction analysis. Atom-atom non-bonded potential energy and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 3 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.9(1)–93.5(5)°) to the xanthene rings. The bond lengths C(6)O(2) are apparently extended from the normal C(sp 3O (lactone) length. The temperature factors for one butyl group C(32)C(35)) of 1 increase gradually toward the terminal carbon. The temperature factors for C(30)C(33) of 2 indicate large vibrations and these are reflected in short bond lengths. Two butyl groups of 3 are disordered and these CC bond lengths are short and long alternately. Atomic net charges around spirocarbon C(6) and toward N(1) to C(6) indicate the weak alternative system in the colorless form. As the xanthene ring has a planar geometry, the π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring.

X-ray crystal structure analysis and atomic charges of color former and developer: 2. Color formers

The crystal and molecular structures of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one (1), 2′-amino-6′-( N-cyclohexyl- N-methylamino)-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one (2) and 2′-(2-chlorophenyl)amino-6′-dibutylaminospiro[isobenzofuran-1(3 H), 9′[9 H]xanthen-3-one (3) have been determined by single-crystal X-ray diffraction analysis. Atom-atom non-bonded potential energy and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 3 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.9(1)−93.5(5)°) to the xanthene rings. The bond lengths C(6)O(2) are apparently extended from the normal C(sp 3)O (lactone) length. The temperature factors for one butyl group C(32)C(35)) of 1 increase gradually toward the terminal carbon. The temperature factors for C(30)C(33) of 2 indicate large vibrations and these are reflected in short bond lengths. Two butyl groups of 3 are disordered and these CC bond lengths are short and long alternately. Atomic net charges around spirocarbon C(6) and toward N(1) to C(6) indicate the weak alternative system in the colorless form. As the xanthene ring has a planar geometry, the π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring.

Re-examination of the 13C NMR spectrum of xanthene: a revised correlation for the carbocyclic ring 3JCHmeta-coupling constants in fused oxygen heterocycles

13C Chemical shifts and J CH coupling constants are reported for xanthene and for some dimedone adducts containing a xanthene ring. A revised correlation pattern for the carbocyclic ring 3 J CH meta-couplings in fused oxygen heterocycles is proposed in which the magnitude of the interactions alternate around the ring.

Phosphorescence Probes of the Glassy State in Amorphous Sucrose

AbstractWe have used phosphorescence from the luminescent chromophores N‐acetyltryp‐tophanamide (NATA) and erythrosin B (Ery B) to probe the molecular dynamics of the glassy state and the glass‐to‐rubber transition in amorphous sucrose. These measurements exploit the known sensitivity of phosphorescence intensity to the rate and extent of molecular collisions with the local environment. Both probes exhibit intense, well‐defined phosphorescence emission spectra in the glassy sugar matrix. Time‐resolved phosphorescence intensity decays for each probe were multiexponential both above and below the glass transition temperature, indicating that the sucrose matrix is heterogeneous on the molecular level; local microviscosities around the NATA probe were estimated in the range from 104 to 5 × 107 Pa·s in the glassy state at 25 °C. Plots of phosphorescence lifetime versus temperature for both probes are linear above and below the glass transition temperature of sucrose (62 °C), but exhibit a break in slope near approximately 50 °C characteristic of a dramatic change in the rate of molecular collision between the probe and the local environment. The similar sensitivity of two chemically different spectroscopic probes (the indole ring of NATA and the xanthene ring of Ery B) to molecular changes near the glass transition in this sugar indicates that phosphorescence may provide a generally applicable, site‐specific probe of the glassy state and changes in it in biological materials.

Fluorescence spectroscopy of monoclonal antibodies produced against the fluorescyl hapten conjugated through the xanthene ring

Two mouse anti-fluorescyl monoclonal antibodies (mAb), clones FL43.1 and FL55.3, were produced to the fluorescein hapten, which was conjugated to the carrier protein through the 4' position of the xanthene ring. Association constants (K A) and thermodynamic parameters for both mAb were ascertained by monitoring the steady-state intrinsic and fluorescein fluorescence. Both techniques were in good agreement and gaveK A values in the 10(9) M (-1) range. Ligand-induced intrinsic fluorescence quenching showed a hypsochromic shift for mAb FL43.1, but not for FL55.3, suggesting that the ligand interacts with different tryptophan residues in each mAb. Because these mAb are directed toward the phenylcarboxylate portion of fluorescein, the different ionic and structural forms should be useful as indicators of antibody binding site pH and buffering capacity near the binding site.

Luminescent/paramagnetic probes of order and orientation in biological assemblies: the transformation of luminescent probes into pi-radicals by photochemical reduction within the contractile apparatus.

Several unsubstituted xanthene dyes (eosin, erythrosin, and fluorescein) were irradiated by laser light at their absorption maximum in the presence of different reducing agents. Due to photochemical reduction the quinoidal structure of the xanthene ring is transformed into a semiquinone and a pi-radical is formed having a characteristic electron paramagnetic resonance (EPR) signal of an unpaired electron spin with proton hyperfine interactions. A strong EPR signal is observed from the dye in solution or when specifically attached to myosin following irradiation in the presence of dithiothreitol or cysteine. The spectroscopic methods of fluorescence polarization and EPR are useful in the study of ordered biological assemblies. These methods generate complementary information about the order of the system but a consistent quantitative interpretation of the related data is complicated because the signals arise from different donors. Our method allows us to detect both signals from the same donor. We applied our new technique to the study of skeletal muscle fibers. The fluorescent dye iodoacetamidofluorescein was covalently attached to the reactive thiol of the myosin molecule in muscle fibers. Fluorescence polarization and EPR spectroscopy were performed on the labeled fibers in rigor. Both signals indicate a highly ordered system characteristic of cross-bridges bound to actin.

Luminescent/paramagnetic probes for detecting order in biological assemblies: transformation of luminescent probes into pi-radicals by photochemical reduction.

The spectroscopic methods of fluorescence polarization and electron paramagnetic resonance (EPR) are used to study order and orientation of extrinsically labeled protein elements of ordered biological systems. These methods generate complementary information about the order of the system, but a consistent quantitative interpretation of the related data is complicated because the signals arise from different donors. We introduce a new method that allows us to detect both signals from the same donor. Unsubstituted xanthene dyes (eosin, erythrosin, and fluorescein) were irradiated by laser light at their absorption maximum in the presence of different reducing agents. Due to photochemical reduction, the quinoidal structure of the xanthene ring is transformed into a semiquinone, and a pi-radical is formed having a characteristic EPR signal of an unpaired electron spin with proton hyperfine interactions. A strong EPR signal is observed from the dye in solution or when specifically attached to a protein following irradiation in the presence of dithiothreitol or cysteine. We applied this technique to the study of skeletal muscle fibers. The fluorescent dye (iodoacetamido)fluorescein was covalently attached to the reactive thiol of the myosin molecule in muscle fibers. Fluorescence polarization and EPR spectroscopy were performed on the labeled fibers in rigor. Both signals indicate a highly ordered system characteristic of cross-bridges bound to actin. Our use of the same signal donor for fluorescence and EPR studies of probe order is a promising new technique for the study of order in protein elements of biological assemblies.

Fourier transform Raman and infrared and surface-enhanced Raman spectra for rhodamine 6G

The vibrational spectra of rhodamine 6G (R6G) are discussed on the basis of Fourier transform infrared and Fourier transform Raman spectra obtained far from resonance which are compared with resonance Raman and surface-enhanced resonance Raman spectra obtained with excitation at 457.9 nm. The behaviour of several bands is described and tentative assignments are proposed. Stong resonance Raman effects are observed for bands assignable to xanthene ring stretching modes and also xanthene ring deformation modes. Some of these are sensitive to the complexing of R6G with silver colloids.

Effect of solvent polarity on nonradiative processes in xanthene dyes: Rhodamine B in normal alcohols

The fluorescence lifetime of rhodamine B in a series of normal alcohols (C/sub n/H/sub 2n-1/OH, n = 1-6) was measured as a function of temperature. The nonradiative rate constants were calculated from the fluorescence lifetimes and quantum yields. Activation energies were obtained from Arrhenius plots of the nonradiative rate constant. The variation of the nonradiative rate constant with solvent polarity and temperature was consistent with a photophysical mechanism that involves equilibrium between the planar and twisted configurations of the diethylamino groups on the xanthene ring of rhodamine B and internal conversion from the twisted configuration. The activation energy is equal to the free energy difference between the twisted and planar configurations. The solvent polarity dependence of the free energy difference and of the rate constant for internal conversion from the twisted configuration determines the variation of the nonradiative rate constant with solvent. When solvent polarity effects are taken into account by using the parameter E/sub T/(30), the nonradiative rate constant shows weak or no dependence on the solvent viscosity.

Electronic Structure and Spectra of Organic Dye Anions of Uranine and Eosin Y

Abstract The excited states of the organic dye anions of Uranine and Eosin Y are invesitigated by the semi-empirical SCF-MO-CI calculations. The two-center core integral values of the C–Br bond (−0.20 eV) were determined. Agreement between the calculated and observed spectra was satisfactory. The first intense bands of these dye anions can be assigned to the HOMO→LUMO transition band arising from the local excitation of xanthene ring. The second bands are interpreted as the overlap of the two transition bands for the xanthene ring and for the residual π-systems.

Toxic effects of ouabain and food and cosmetic dyes on nerve growth factor‐promoted differentiation of neurites in culture

AbstractThe toxic effects of ouabain and various fluorescein analogs have been tested on nerve growth factor‐promoted (NGF‐promoted) outgrowth of neurites from embryonic chick sensory ganglia embedded in a matrix of native collagen. Ouabain inhibits outgrowth with an IC50 of approximately 5 μM. Erythrosin B (USFD&C Red 3) and other fluorescein derivative dyes brominated or iodinated on the xanthene ring also inhibit neurite outgrowth with IC50'S as low as 10 μm and promote early retraction of growing neurites. The effects of the dyes are due, at least in part, to photooxidation of the NGF, but they may also act directly on the cells. The culture system should prove useful as both a general and a specific in vitro assay for neurotoxicity.

The synthesis of 3H‐pyrazol‐3‐one derivatives containing a 9H‐xanthene ring

Abstract2,4‐Dihydro‐5‐methyl‐2‐phenyl‐4‐(9H‐xanthen‐9‐yl)‐3H‐pyrazol‐3‐one (3) was prepared by the condensation of phenylhydrazine and ethyl α‐acetyl‐9H‐xanthene‐9‐acetate (2), or 9H‐xanthen‐9‐ol (1) and 2,4‐dihydro‐5‐methyl‐2‐phenyl‐3H‐pyrazol‐3‐one (4). 5‐Amino‐2,4‐dihydro‐2‐phenyl‐4‐(9H‐xanthen‐9‐yl)‐3H‐pyrazol‐3‐one (6) was obtained by the condensation of 1 and 5‐amino‐2,4‐dihydro‐2‐phenyl‐3H‐pyrazol‐3‐one (5).

ChemInform Abstract: ESR STUDY ON FLUORESCEIN SEMIQUINONE RADICAL

Chemischer InformationsdienstVolume 5, Issue 48 Physical Organic Chemistry ChemInform Abstract: ESR STUDY ON FLUORESCEIN SEMIQUINONE RADICAL SHIGEYA NIIZUMA, SHIGEYA NIIZUMASearch for more papers by this authorYOSHIHARU SATO, YOSHIHARU SATOSearch for more papers by this authorSHIRO KONISHI, SHIRO KONISHISearch for more papers by this authorHIROSHI KOKUBUN, HIROSHI KOKUBUNSearch for more papers by this author SHIGEYA NIIZUMA, SHIGEYA NIIZUMASearch for more papers by this authorYOSHIHARU SATO, YOSHIHARU SATOSearch for more papers by this authorSHIRO KONISHI, SHIRO KONISHISearch for more papers by this authorHIROSHI KOKUBUN, HIROSHI KOKUBUNSearch for more papers by this author First published: December 3, 1974 https://doi.org/10.1002/chin.197448096AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume5, Issue48December 3, 1974 RelatedInformation

ESR Study on Fluorescein Semiquinone Radical

Abstract The ESR spectrum of the fluorescein semiquinone radical (dianion form) produced by illumination of an alkaline aqueous solution of uranine and leuco-uranine at pH between 11 and 14 was observed and its hfs constants were determined by comparing the spectrum with those of the mono- and trianion forms of fluorescein semiquinone and those of eosm semiquinone reported by Leaver. Six protons in the xanthene ring were found to be comprised of three pairs of magnetically equivalent protons, which suggests a certain dynamic mechanism to average the coupling constants. From a temperature dependence of the line width, protonation to the –O− group followed by deprotonation from the –OH group was proposed as a plausible mechanism.

キサンテン-9-置換体の合成 (第3報)

1) Preparation of the ammonium salts of carboxylic alkamine esters possessing structures similar to β-diethylaminoethylxanthene-9-carboxylate methobromide was carried out and comparative examination of their pharmacological action was made.2) The compounds substituted with phenyl (IX) and o-tolyl (X) in 9-position of the xanthene ring possessed very weak antiacetylcholinergic and antihistamine actions, possessed a high toxicity, and only a slightly stronger antibarium chloride activity.3) A substance in which -CH2- (XI) or -CH (CH3)- (XII) was substituted between 9-position of the xanthene ring and the carboxyl group possessed weak antiacetylcholinergic, antibarium chloride, and antihistamine actions while there was no change in toxicity. However, antiacetylcholinergic action was stronger than those of (IX), (X), and (XII).4) The variation by each chemical and by the difference in experimental animals and intestinal specimens against experimental error was found to be significant in the difference between the chemical and animal.