Room-temperature phosphorescence of anilinonaphthalenesulfonate “fluorescence probe” compounds (original) (raw)
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Chemical Physics Letters, 2011
Berberine and coralyne experience either fluorescence enhancement or quenching when long hydrocarbon chain compounds (e.g., n-alkanes or alcohols) are added to their solutions, depending on solvent polarity. In polar solvents, as methanol or acetonitrile, the added compounds provide an apolar microenvironment that hinders alternative relaxation mechanisms, favouring fluorescence emission. However, alkane additions produce quenching in dichloromethane, which has been explained taking into account ion pairing between cationic fluorophore and counterion. The strong quenching measured after alcohol additions in dichloromethane suggests reversed micelle formation. Procedures and results described here may find practical applications in the development of analytical methods.
Resolution of the excited states of the fluorescence probe TNS using a trilinear analysis technique
The Journal of Physical Chemistry, 1995
The technique of trilinear analysis was applied to characterize the steady-state room-temperature fluorescence of the probe 2-@-toluidino)naphthalene-6-sulfonate (TNS) in various solvents. Our approach recognizes that the fluorescence of a mixture of fluorophores is separately linear in each of the independent variables of excitation wavelength, emission wavelength, and probe concentration. We confirmed the sensitivity of TNS emission to solvent characteristics and resolved the contributions of three distinct components to the overall TNS fluorescence spectrum. Our results are consistent with the existence of three distinct excited states and further demonstrate that the limitation of previous studies to a single excitation wavelength led to an incomplete characterization of TNS emission in aqueous solutions. TNS fluorescence is attributed to emission from the conventional nn* excited state with a nonplanar orientation of the phenyl and naphthalene rings, from a charge-transfer state with a coplanar arrangement of the ring systems, and from a charge-transfer state with a nonplanar ring orientation induced by protonation of or hydrogen bonding to the bridging nitrogen atom.
Chemical Communications, 2005
General. Melting points (Mp), determined on a Yanako melting point apparatus, are uncorrected. 1 H-NMR spectra were determined on a JEOL LA-500 spectrometer (500 MHz) or a JEOL JNM-ECP600 spectrometer (600 MHz). 13 C-NMR spectra were determined on a JEOL JNM-ECP600 spectrometer (150 MHz). Chemical shifts for 1 H-NMR were reported in parts per million (ppm) downfield from tetramethylsilane as the internal standard and coupling constants (J) are in Hertz (Hz). The following abbreviations are used for spin multiplicity: s = singlet, d = doublet, t = triplet, dd = doublet of doublet, m = multiplet, and br = broad. Chemical shifts for 13 C-NMR were reported in ppm relative to the central line of a triplet at 77.0 ppm for deuteriochloroform and coupling constants (J) are in Hertz (Hz). Infrared (IR) spectra were recorded on a JASCO FT/IR-8000 Fourier Transform Infrared Spectrophotometer and are reported in wavenumbers (cm-1). High resolution mass spectra (HRMS) were obtained on a JEOL JMS-SX 102A. UV-vis absorption spectra were obtained on a Shimadzu UV-260 spectrophotometer. Fluorescence spectra were obtained on a Shimadzu RF-5000 fluorescence spectrophotometer. Analytical thin layer chromatography (TLC) was performed on HPTLC aluminium sheets, silica gel 60 F 254 (Merck). Open column chromatography was performed on Merck silica gel 60 (70-230 mesh). Preparative TLC (PTLC) was performed on 6.7 × 20 cm Merck precoated analytical plates, 0.50 mm thick, silica gel 60 F 254. Reagents and solvents were commercial grades and were used as supplied. THF and DMF were purchased anhydrous. Chlorodiethylphosphine was purchased from Acros Organics.
Analytica Chimica Acta, 2000
We present here the first confirmation that the new methodology of room-temperature phosphorescence emission named heavy-atom induced room-temperature phosphorescence (HAI-RTP), can be observed for both polycyclic aromatic hydrocarbons and nitrogen heterocycles. This methodology makes use of RTP emission directly from the analyte in fluid solution, without a protective medium but only with the presence of high concentrations of heavy atom perturbers. This permits a sufficient interaction between the perturbers and the analytes to produce effective population of their triplet states, and consequently, an intense phosphorescent emission. Good deoxygenation conditions are obtained using sodium sulfite as the oxygen scavenger. In order to confirm this new phosphorescence methodology, a wide variety of compounds, with different chemical structure, have been selected. In this work, polycyclic aromatic hydrocarbons as naphthalene derivatives (naphthylacetic acid, ␣-naphthalene acetamide, naproxen, nafronyl, dansylamide and carbaryl) and fluorene and several nitrogen heterocyclic compounds as benzimidazole derivatives (thiabendazole), carbazole, indole derivatives (tryptamine, tryptophan and indole-3-butyric acid) and an acridine derivative (9-hydroxy-4-methoxyacridine), have been studied. Phosphorescence spectral characteristics of these compounds (excitation and emission wavelengths and lifetime) and the optimization of the chemical variables involved in the phosphorescence phenomenon in solution, are reported. Under optimal experimental conditions, calibration graphs and detection limit in the ng ml −1 level, have been established.
Molecular Fluorescence, Phosphorescence, and Chemiluminescence Spectrometry
Analytical Chemistry, 2002
Page 1. Molecular Fluorescence, Phosphorescence, and Chemiluminescence Spectrometry Mark Lowry,† Sayo O. Fakayode,‡ Maxwell L. Geng,§ Gary A. Baker,| Lin Wang, ⊥ Matthew E. McCarroll, ⊥ Gabor Patonay,X and Isiah M. Warner*,† ...
New Fluorescence Probes for Biomolecules
Molecules, 2015
Steady state fluorescence measurements have been used for the investigation of interaction between the bovine serum albumin (BSA) and fluorescence probes: 3-hydroxy-2,4bis[(3-methyl-1,3-benzoxazol-2(3H)-ylidene)methyl]cyclobut-2-en-1-one (SQ6), 3-hydroxy-2,4-bis[(3-methyl-1,3-benzothiazol-2(3H)-ylidene)methyl]cyclobut-2-en-1-one (SQ7) and 3-hydroxy-2,4-bis[(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidene)methyl]cyclobut-2-en-1-one (SQ8). The binding constant between bovine serum albumin and squarine dyes has been determined by using both the Benesi-Hildebrand and Stern-Volmer equations. The negative value of free energy change indicates the existence of a spontaneous complexation process of BSA with squarine dyes.
Chemical Physics, 2009
The fluorescence spectroscopic behaviour of (6R,S)-5,10-methenyltetrahydrofolate (MTHF), (6R,S)-10formyltetrahydrofolate (10-HCO-H4folate), 10-formyldihydrofolate (10-HCO-H2folate), and 10-formylfolate (10-HCO-folate) in aqueous Tris-HCl buffer at pH 8 is studied. MTHF and 10-HCO-folate were commercially available. 10-HCO-H4folate was prepared from MTHF by hydrolysis at room temperature under anaerobic conditions. 10-HCO-H2folate was prepared by oxidation of 10-HCO-H4folate under aerobic conditions. Fluorescence quantum distributions at room temperature and fluorescence signal decays at room temperature and liquid nitrogen temperature were measured. The fluorescence lifetimes determined at room temperature (liquid nitrogen temperature) are 10 ps (2.9 ns) for MTHF, 38 ps (3.7 ns) for 10-HCO-H4folate, 80 ps (10.5 ns) for 10-HCO-H2folate, and 7.1 ns (20 ns) for 10-HCO-folate. The results are discussed in terms of dyadic (pterin-benzoyl-glutamate) photo-induced electron transfer and dyadic fluorescent dynamics.