Fluorometric Properties of N-Methyltetraphenylporphine and Several Derivatives: Evaluation as Standards for Determination of Chlorophyll Concentrations

1982 ◽  
Vol 36 (4) ◽  
pp. 430-435 ◽  
Author(s):  
David K. Lavallee ◽  
Thomas J. McDonough ◽  
Lisa Cioffi
Keyword(s):  
Chlorophyll A ◽  
Organic Solvents ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Quantum Yields ◽  
Polar Organic Solvents ◽  
Solvent Systems ◽  
Nonpolar Organic ◽  
Chlorophyll Concentrations

As part of an ongoing study of the chemistry and properties of N-methylporphyrins and their metal complexes, we have observed that the excitation and emission spectra of N-methyltetraphenylporphyrin and N-methyltetra( p-sulfophenyl)porphyrin and their zinc complexes closely resemble corresponding spectra of chlorophyll a. We have characterized fluorescence spectra for these species in a variety of solvents commonly used for quantitative determination of chlorophylls. Quantum yields for the N-methylporphyrins are lower by approximately a factor of 10 than yields for chlorophyll a in such solvents as acetone, ethanol, and mixed aqueous/organic solvent systems. The yields are quite sufficient, however, for these species to be used as fluorescence standards. Solution of N-methylporphyrins are stable and the compounds can be inexpensively synthesized in high purity. The tetra( p-sulfophenyl) species are soluble in aqueous and highly polar organic solvents, whereas the tetraphenyl species are soluble in nonpolar organic solvents.

The Synthesis and Electroluminescence Properties of 4-Benzofuranyl-1,8-Naphthalimide Derivatives

2012 ◽  
Vol 557-559 ◽  
pp. 1031-1036 ◽  
Author(s):  
Jian Xin Yang ◽  
Xiang Hui Wang
Keyword(s):  
Absorption Spectra ◽  
Fluorescence Spectra ◽  
Cycloaddition Reaction ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Quantum Yields ◽  
Absorption And Fluorescence Spectra ◽  
Maximum Brightness ◽  
Maximum Emission ◽  
Mild Conditions

A series of fluorescence compounds, 4-benzofuranyl-1,8-naphthalimides, were prepared through cycloaddition reaction from 4-ethynyl-1,8-naphthalimides and o-iodophenols which catalyzed by a Pd(PPh3)2Cl2 / CuI system under mild conditions. The intermediate material, 4-ethynyl-1,8- naphthalimide, was synthesized from 4-bromo-1,8- naphthalimide and trimethylsilyl- acetylene. The absorption and fluorescence spectra of 4-benzofuranyl-1,8- naphthalimides were studied and the quantum yields were measured. The maximum UV/vis absorption spectra were in the range of 375-400 nm and the maximum emission spectra were in the range of 470-510 nm. The electro- luminescent properties were also mensurated through a doped electroluminescent device which contains 1% 1,8-naphthalimides and 99% CBP (4,4'-N,N'-dicarbazole-biphenyl), It’s shown the maximum brightness reached 3700 cd/ m2 at 22.5V.

The wormlike micelles formed using an ionic liquid surfactant and polar organic solvents at low temperature without additives and their lubricant properties

Soft Matter ◽  
2021 ◽  
Author(s):  
Huijiao Cao ◽  
Wenlin Xu ◽  
Xia Guo
Keyword(s):  
Ionic Liquid ◽  
Low Temperature ◽  
Organic Solvent ◽  
Organic Solvents ◽  
Wormlike Micelles ◽  
Polar Organic Solvents ◽  
Ionic Liquid Surfactant ◽  
Nonpolar Organic

Wormlike micelles (or reverse wormlike micelles) are flexible cylindrical chains that are normally formed in water (or a nonpolar organic solvent) at 25.0 °C or above; the formation of wormlike micelles at lower temperatures is rare.

scholarly journals Prevention of H-Aggregates Formation in Cy5 Labeled Macromolecules

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Jing Kang ◽  
Oliver Kaczmarek ◽  
Jürgen Liebscher ◽  
Lars Dähne
Keyword(s):  
Quantitative Determination ◽  
Organic Solvents ◽  
Conformational Changes ◽  
Fluorescence Spectra ◽  
Cyanine Dye ◽  
Inhomogeneous Distribution ◽  
Aggregate Formation ◽  
Absorption And Fluorescence Spectra ◽  
Covalent Linkage

H-aggregates of the cyanine dye Cy5 are formed during covalent linkage to the cationic macromolecule Poly(allylamine) (PAH). The nonfluorescent H-aggregates strongly restrict the usage of the dye for analytical purposes and prevent a quantitative determination of the labeled macromolecules. The behavior of the H-aggregates has been studied by investigation of the absorption and fluorescence spectra of the dye polymer in dependence on solvent, label degree and additional sulfonate groups. H-aggregate formation is caused by an inhomogeneous distribution of the Cy5 molecules on the polymer chain. The H-aggregates can be destroyed by conformational changes of the PAH induced by interactions with polyanions or in organic solvents. It has been found that the polymer labeling process in high content of organic solvents can prevent the formation of H-aggregates. The results offer a better understanding and improvement of the use of the Cy5 dye for labeling purposes in fluorescence detection of macromolecules.

scholarly journals Об экспериментальном определении параметров интенсивности 4f-4f-переходов по спектрам излучения соединений европия (III)

2022 ◽  
Vol 130 (1) ◽  
pp. 207
Author(s):  
Lucca Blois ◽  
Albano N. Carneiro Neto ◽  
Ricardo L. Longo ◽  
Israel F. Costa ◽  
Tiago B. Paolini ◽  
...  
Keyword(s):  
Unique Feature ◽  
Photon Counting ◽  
Emission Spectra ◽  
Lanthanide Ions ◽  
Quantum Yields ◽  
Correction Factors ◽  
Intensity Parameters ◽  
Trivalent Lanthanide ◽  
Integrated Intensity

Eu3+ complexes and specially β-diketonate compounds are well known and studied in several areas due to their luminescence properties, such as sensors and lightning devices. A unique feature of the Eu3+ ion is the experimental determination of the 4f-4f intensity parameters Ωλ directly from the emission spectrum. The equations for determining Ωλ from the emission spectra are different for the detection of emitted power compared to modern equipment that detects photons per second. It is shown that the differences between Ωλ determined by misusing the equations are sizable for Ω4 (ca. 15.5%) for several Eu3+β-diketonate complexes and leads to differences of ca. 5% in the intrinsic quantum yields Q_Ln^Ln. Due to the unique features of trivalent lanthanide ions, such as the shielding of 4f-electrons, which lead to small covalency and crystal field effects, a linear correlation was observed between Ωλ obtained using the emitted power and photon counting equations. We stress that care should be exercised with the type of detection should be taken and provide the correction factors for the intensity parameters. In addition, we suggest that the integrated intensity (proportional to the areas of the emission band) and the centroid (or barycenter) of the transition for obtaining Ωλ should be determined in the properly Jacobian-transformed spectrum in wavenumbers (or energy). Due to the small widths of the emission bands of typical 4f-4f transitions, the areas and centroids of the bands do not depend on the transformation within the experimental uncertainties. These assessments are relevant because they validate previously determined Ωλ without the proper spectral transformation.

scholarly journals Poly(Pyridinium Salt)s Containing 2,7-Diamino-9,9′-Dioctylfluorene Moieties with Various Organic Counterions Exhibiting Both Lyotropic Liquid-Crystalline and Light-Emitting Properties

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1560
Author(s):  
Pradip K. Bhowmik ◽  
Tae S. Jo ◽  
Jung J. Koh ◽  
Jongwon Park ◽  
Bidyut Biswas ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Liquid Crystalline ◽  
Average Molecular Weight ◽  
Pyridinium Salt ◽  
Emission Spectra ◽  
Ionic Polymers ◽  
Scanning Calorimetry ◽  
Light Emitting ◽  
Chemical Structures ◽  
Nonpolar Organic

A series of poly(pyridinium salt)s-fluorene main-chain ionic polymers with various organic counterions were synthesized by using ring-transmutation polymerization and metathesis reactions. Their chemical structures were characterized by Fourier Transform Infrared (FTIR), proton (1H), and fluorine 19 (19F) nuclear magnetic resonance (NMR) spectrometers. These polymers showed a number-average molecular weight (Mns) between 96.5 and 107.8 kg/mol and polydispersity index (PDI) in the range of 1.12–1.88. They exhibited fully-grown lyotropic phases in polar protic and aprotic solvents at different critical concentrations. Small-angle X-ray scattering for one polymer example indicates lyotropic structure formation for 60–80% solvent fraction. A lyotropic smectic phase contains 10 nm polymer platelets connected by tie molecules. The structure also incorporates a square packing motif within platelets. Thermal properties of polymers were affected by the size of counterions as determined by differential scanning calorimetry and thermogravimetric analysis measurements. Their ultraviolet-visible (UV-Vis) absorption spectra in different organic solvents were essentially identical, indicating that the closely spaced π-π* transitions occurred in their conjugated polymer structures. In contrast, the emission spectra of polymers exhibited a positive solvatochromism on changing the polarity of solvents. They emitted green lights in both polar and nonpolar organic solvents and showed blue light in the film-states, but their λem peaks were dependent on the size of the counterions. They formed aggregates in polar aprotic and protic solvents with the addition of water (v/v, 0%–90%), and their λem peaks were blue shifted.

scholarly journals Analysis of luminescence of Eu3+ doped Lu2Ti2O7 powders with Judd-Ofelt theory

2015 ◽  
Vol 38-39 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Katarina Vuković ◽  
Sanja Ćulubrk ◽  
Milica Sekulić ◽  
Miroslav D. Dramićanin
Keyword(s):  
Emission Spectra ◽  
Quantum Yields ◽  
Optical Parameters ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Ofelt Theory ◽  
The Face ◽  
Face Centered ◽  
The Eu

Abstract Eu3+ doped Lu2Ti2O7 particles of 6 to 10 nm in diameter are prepared by Pechini-type polymerized complex route based on polyesterification between citric acid (CA) and ethylene glycol. X-ray diffraction measurements confirmed that Eu3+ doped Lu2Ti2O7 powders crystallized in the face-centered cubic lattice (Fd3m). Emission spectra displayed characteristic 5D0 →7 FJ (J = 0, 1, 2, 3 and 4) spin forbidden f-f electronic transitions of the Eu3+ ions with the most pronounced emission coming from 5D0 →7 F2 and with the emission decays varying between 0.75 and 0.60 ms for samples doped with different concentration of Eu3+. The Judd-Ofelt theory was applied to the experimental data for the quantitative determination of optical parameters such as Ω2, Ω4 Judd-Ofelt parameters, radiative and nonradiative transition rates and emission quantum efficiency. It was observed that, for all the samples, Ω2 >> Ω4. The luminescence quantum yields were calculated by means of the Judd-Ofelt theory and the highest value 60.83 % is obtained for particles doped with concentration of 3 % Eu3+.

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