Regioisomeric synthesis of chlorin-e6 dimethyl esters and their optical properties

2018 ◽  
Vol 22 (12) ◽  
pp. 1039-1046 ◽  
Author(s):  
Yasunobu Nagano ◽  
Shin Ogasawara ◽  
Hitoshi Tamiaki
Keyword(s):  
Optical Properties ◽  
Absorption Spectra ◽  
Carboxy Group ◽  
Fluorescence Emission ◽  
Substitution Effect ◽  
Molecular Structures ◽  
Chlorin E6 ◽  
Visible Absorption ◽  
Methyl Esterification ◽  
Hydrolysis Of

Chlorin-[Formula: see text] dimethyl esters possessing a single carboxy group at the 13-, 151-, or 172-position were prepared by chemically modifying chlorophyll-[Formula: see text]. These three synthetic regioisomers were fully characterized by their mass, NMR, and visible absorption spectra. Their molecular structures were unambiguously identified by the specific 1H–[Formula: see text]C correlation at the 13-, 15-, and/or 17-substituents in their respective HMBC spectra. Methyl esterification of 13/151-COOH and hydrolysis of 13/151-COOMe affected small shifts of the Qy absorption and fluorescence emission maxima in a diluted CH2Cl2 solution, while no substitution effect of 172-COOH/Me was observed.

Syntheses and crystal structures of guanidine hydrochlorides with two Schiff base functions as efficient colorimetric and selective sensors for fluoride

2018 ◽  
Vol 73 (8) ◽  
pp. 601-609 ◽  
Author(s):  
Bei Wang ◽  
Pei-Zhi Zhang ◽  
Xin Chen ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Optical Properties ◽  
Schiff Base ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Guanidinium Chloride ◽  
Visible Absorption ◽  
X Ray ◽  
Color Changes ◽  
Base Functions ◽  
Magnetic Resonances

AbstractA series of guanidinium chloride derivatives have been synthesized by condensation of 1,3-diaminoguanidine monohydrochloride with heteroaromatic formaldehydes in good yields. All compounds were characterized by nuclear magnetic resonances and infrared spectroscopies, and the molecular structures of four compounds were determined by single crystal X-ray diffraction. The optical properties of these guanidinium chloride derivatives with fluoride anions were investigated, showing selective color changes from colorless to yellow or orange, red-shifted in the ultraviolet/visible absorption spectra.

scholarly journals Density Functional Theory Study on the Electronic Structures of Oxadiazole Based Dyes as Photosensitizer for Dye Sensitized Solar Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Umer Mehmood ◽  
Ibnelwaleed A. Hussein ◽  
Khalil Harrabi ◽  
Shakeel Ahmed
Keyword(s):  
Density Functional Theory ◽  
Absorption Spectra ◽  
Density Functional ◽  
Energy Levels ◽  
Dye Sensitized Solar Cells ◽  
Electron Injection ◽  
Molecular Structures ◽  
Visible Absorption ◽  
Functional Theory ◽  
Oxidation Potentials

The molecular structures and UV-visible absorption spectra of complex photosensitizers comprising oxadiazole isomers as theπ-bridges were analyzed by density functional theory (DFT) and time-dependent DFT. The ground state and excited state oxidation potentials, HOMOs and LUMOs energy levels, and electron injection from the dyes to semiconductor TiO2have been computed in vacuum here. The results show that all of the dyes may potentially be good photosensitizers in DSSC. To justify the simulation basis, N3 dye was also simulated under the similar conditions. Simulated absorption spectrum, HOMO, LUMO, and band gap values of N3 were compared with the experimental values. We also computed the electronic structure properties and absorption spectra of dye/(TiO2)8systems to elucidate the electron injection efficiency at the interface. This work is expected to give proper orientation for experimental synthesis.

scholarly journals Studies on pigments of the myxomycete Physarum nudum. II. Separation and optical properties of the pigments from plasmodia cultured in darkness

2015 ◽  
Vol 41 (3) ◽  
pp. 411-423
Author(s):  
L. Raczkowski
Keyword(s):  
Optical Properties ◽  
Acid Solution ◽  
Thin Layer ◽  
Physical Properties ◽  
Thin Layer Chromatography ◽  
Absorption Spectra ◽  
Fluorescence Emission ◽  
Dark Pigment ◽  
Rf Values ◽  
Layer Chromatography

The paper presents the data on Separation and some optical properties of the pigments obtained from the plasmodium of the myxomycete <i>Physarum nudum</i> grown in the dark. Pigment Separation was performed by means of thin-layer chromatography with celulose MN 300 as adsorbent and with the solvent: tert.-butylalcohol, H<sub>2</sub>O, 3N NH<sub>4</sub>OH at the ratio 5:2:1 In these conditions the chromatograms revealed 12 coloured bands from which pigments were eluted and their absorption spectra as well as the spectra of fluorescence emission were determined. The isolated pigments differ from one another by their physical properties (different Rf values, localization of absorption maxima, and behaviour in acid solution). Nevertheless, certain analogies perceptible between particular pigments per-mitted to distinguish 3 families of the studied pigments demonstrating similar properties.

Structural stability and optical properties of nanocrystalline zirconia

2010 ◽  
Vol 43 (4) ◽  
pp. 780-789 ◽  
Author(s):  
Sujit Manna ◽  
Tandra Ghoshal ◽  
A. K. Deb ◽  
S. K. De
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Temperature Stability ◽  
Band Gap Energy ◽  
Solvothermal Reaction ◽  
Cubic Phase ◽  
Visible Absorption ◽  
Size Growth ◽  
Crystallite Sizes ◽  
Hydrolysis Of

Nanoparticles of the cubic phase of zirconia (ZrO2) of size range 4.5–8.7 nm have been synthesized by alkaline hydrolysis of a zirconium salt followed by solvothermal reaction. Subsequently, the room-temperature stability of cubic ZrO2nanoparticles has been explored with the goal of understanding how crystal structure tends to transform into a structure of higher symmetry with decreasing crystallite size. The room-temperature-stable cubic phase in nanosized ZrO2has been observed to transform into the monoclinic phase at 873 K. The crystalline phases of ZrO2nanocrystals have been determined quantitatively by Rietveld refinement. Lattice constant and internal strain increase with decreasing particle size. Growth kinetics studies have established that cubic nanocrystals are more stable at smaller crystallite sizes. UV–visible absorption spectra show an absorption peak at 275 nm which indicates a lowering of the band gap energy. Photoluminescence spectra of zirconia nanoparticles show an emission peak at 305 nm at room temperature. The modification of the optical properties is explained on the basis of oxygen vacancies present within the samples.

scholarly journals Optical properties for TiO2 / PMMA nanocomposite thin films prepared by plasma jet

2018 ◽  
Vol 15 (35) ◽  
pp. 24-28
Author(s):  
Saba J. Kadhem
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Titanium Oxide ◽  
Absorption Spectra ◽  
Plasma Jet ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Nanocomposite Thin Films ◽  
Uv Visible

PMMA/TiO2 homogeneous thin films were deposited by using plasma jet system under normal atmospheric pressure and room temperature. PMMA/TiO2 nanocomposite thin film synthesized by plasma polymerization. Titanium oxide was mixed with Methyl Methacrylate Monomer (MMA) with specific weight ratios (1, 3 and 5 grams of TiO2 per 100 ml of MMA). Optical properties of PMMA/TiO2 nanocomposite thin films were characterized by UV-Visible absorption spectra using a double beam UV-Vis-NIR Spectrophotometer. The thin films surface morphological analysis is carried out by employing SEM. The structure analysis are achieved by X-ray diffraction. UV-Visible absorption spectra shows that the increasing the concentration of titanium oxide added to the polymer leads to shift the peak position (λmax) toward the infrared region of the electromagnetic spectrum. Also the peak width increases when the concentration of TiO2 increases. It can be controlled optical energy band gap of PMMA/TiO2 nanocomposite thin films by changing concentration of TiO2. SEM indicate a uniform distribution of titanium oxide particles in PMMA matrix. The x-ray diffraction pattern indicated that the thin films have amorphous structure.

scholarly journals Photophysical Properties of Protoporphyrin IX, Pyropheophorbide-a, and Photofrin® in Different Conditions

2021 ◽  
Vol 14 (2) ◽  
pp. 138
Author(s):  
Bauyrzhan Myrzakhmetov ◽  
Philippe Arnoux ◽  
Serge Mordon ◽  
Samir Acherar ◽  
Irina Tsoy ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Protoporphyrin Ix ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Visible Absorption ◽  
Light Dosimetry ◽  
Time Resolved ◽  
Pyropheophorbide A ◽  
Influence Of Solvent

Photodynamic therapy (PDT) is an innovative treatment of malignant or diseased tissues. The effectiveness of PDT depends on light dosimetry, oxygen availability, and properties of the photosensitizer (PS). Depending on the medium, photophysical properties of the PS can change leading to increase or decrease in fluorescence emission and formation of reactive oxygen species (ROS) especially singlet oxygen (1O2). In this study, the influence of solvent polarity, viscosity, concentration, temperature, and pH medium on the photophysical properties of protoporphyrin IX, pyropheophorbide-a, and Photofrin® were investigated by UV-visible absorption, fluorescence emission, singlet oxygen emission, and time-resolved fluorescence spectroscopies.

Influence of Bi2O3 on Borophosphate Glasses Properties

2014 ◽  
Vol 979 ◽  
pp. 343-346 ◽  
Author(s):  
Natthakridta Chanthima ◽  
Jakrapong Kaewkhao
Keyword(s):  
Optical Properties ◽  
Molar Volume ◽  
Absorption Spectra ◽  
Packing Density ◽  
Visible Range ◽  
Melt Quenching ◽  
Borophosphate Glasses ◽  
Borophosphate Glass ◽  
Uv Visible

Borophosphate glasses have been synthesized with a Bi2O3concentration of 15.0 to 25.0 mol%, added 2.5 mol% for each concentration, by the normal melt quenching technique at 1200 °C. The physical and optical properties of bismuth borophosphate glass systems have been studied. The glasses are characterized for their physical and optical properties. The density and molar volume of these glasses were found in the range 3.4391 to 3.9338 g/cm3and 52.2515 to 55.7557 cm3/mol, respectively. It was observed that the density and molar volume of these glasses was increased with increasing the concentration of Bi2O3. The absorption spectra of these glasses were recorded in the UV-Visible range. It has been found that, the absorption spectra were shifted to longer wavelength with higher Bi2O3concentration. In addition, the oxygen packing density of glass samples have been also investigated.

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