Photophysical and Photochemical Properties of Polyurethane Coumarin Studied by Means of Electronic Spectra

2017 ◽  
Vol 68 (7) ◽  
pp. 1568-1572 ◽  
Author(s):  
Mitachi Strat ◽  
Emil Buruiana ◽  
Dan Dumitriu ◽  
Andrei Victor Sandu ◽  
Silviu Gurlui
Keyword(s):  
Uv Irradiation ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Dimethyl Formamide ◽  
Polar Solvents ◽  
Spectra Analysis ◽  
Photon Excitation ◽  
Exciting Beam ◽  
Photochemical Properties ◽  
Fluorescence Wavelength

The spectroscopic and photochemical properties of polyurethane coumarine (PUC) in dimethyl sulf-oxide (DMSO), thetra hydro furan (THF), dimethyl formamide (DMF) and film state were investigated at room temperature under one photon excitation. Photodimer products were formed via UV irradiation. Syn head-to-head and syn head-to-tail photodimers were formed under one-photon (broadband UV) irradiation in polar solvents. The spectral investigation of the photochemical products of PUC revealed efficient fluorescence emission in the spectral region 300�400 nm, attributed to the syn-head-to-tail dimers of PUC. The results show that under irradiation of l ] 310 nm photodimerization process are increased and under UV irradiation with l [ 260 nm, photocleavage degree have been evidenced, too. Fluorescence spectra analysis of PUC in polar and film-based solvents reveals another very important result. The 375nm fluorescence wavelength of the PUC (exciting beam 310 nm) is about 30 times more intense than the same maximum in THF and in DMF. This result indicates a new method to confirm that PUC film photodimerisation occurs especially at its surface.

The Study of Photoreversibility, Photopolimerization and Photocleavage Properties of Polyurethane Coumarin by Means of Electronic Spectrometry and AFM Methods

2017 ◽  
Vol 68 (7) ◽  
pp. 1632-1635
Author(s):  
Silviu Gurlui ◽  
Emil Buruiana ◽  
Ioan Gabriel Sandu ◽  
Mitachi Strat
Keyword(s):  
Uv Irradiation ◽  
Room Temperature ◽  
Dimethyl Formamide ◽  
Photon Excitation ◽  
Photochemical Properties ◽  
Film State

The spectroscopic and photochemical properties of polyurethane coumarin (PUC) in dimethyl sulf-oxide (DMSO), thetra hydro furan (THF), dimethyl formamide (DMF) and film state were investigated at room temperature under one photon excitation. The results show that under irradiation of l ] 310 nm photodimerization process are increased and under UV irradiation with l[ 260 nm, photocleavage of polymer have been evidenced, too.

Photo-Induced Fluorescence Enhancement of BOPIM–dma in Moderate Polar Solvents

2014 ◽  
Vol 488-489 ◽  
pp. 193-196
Author(s):  
Jin Dong Gong ◽  
Wei Zhang ◽  
Ping Shen ◽  
Ming Xun Yan ◽  
Chang Ying Yang
Keyword(s):  
Charge Transfer ◽  
Uv Irradiation ◽  
Emission Intensity ◽  
Fluorescence Enhancement ◽  
Polar Solvent ◽  
Intramolecular Charge Transfer ◽  
Fluorescence Emission ◽  
Polar Solvents ◽  
Quenching Process ◽  
Fluorescence Emission Intensity

The photo-induced fluorescence enhancement for a BOPIM derivate, which was found weak or no fluorescence in solvents due to twisted intramolecular charge transfer (TICT) was investigated. The quenching process because of TICT state is substantially removed and fluorescence emission intensity increased remarkably, induced by UV-irradiation. This phenomenon could only found in moderate polar solvent, such as CHCl3, THF and 1, 4-dioxane (DIOX), but not in more polarity solvent, such as CH3CN, CH3OH. It is indicated that the transformation from TICT to ICT state take place easily in moderate polar solvents.

scholarly journals Luminescent Hybrid Materials Based on Curcumin Derivatives Embedded in Palygorskite

2018 ◽  
Vol 55 (1) ◽  
pp. 63-67
Author(s):  
Monica Florentina Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Luminita Eugenia Wagner ◽  
Viorica Amariutei ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Hydroxyl Groups ◽  
Fluorescent Properties ◽  
Fluorescence Emission Spectra ◽  
Curcumin Derivatives ◽  
Absorption Studies ◽  
Inorganic Matrix

The seven curcumin derivatives were deposited on palygorskite in order to obtain hybrid materials. The fluorescence emission spectra of the obtained materials show a decrease in fluorescence intensity relative to the respective dyes, due to the environments around the dyestuff molecules created in the host matrices. Absorption studies show the best adsorption on the inorganic matrix, for the compounds with the hydroxyl groups. Correlating fluorescence spectra of hybrid materials with the results for absorption spectra of the dyes adsorbtion on the surface of the clay lead to the conclusion that a high percentage of the adsorbed dye had the effect of fluorescence quenching. Thus, it was confirmed that the fluorescent properties of hybrid materials depend on the interactions established between the fluorescent dyestuff and the inorganic network.

scholarly journals Spectral Properties of Hybrid of Rhodamine (6G) Dyes Doped Epoxy Resin Dissolved in Chloroform

2019 ◽  
Vol 16 (3(Suppl.)) ◽  
pp. 0764 ◽  
Author(s):  
Al-Hamdani Et al.
Keyword(s):  
Epoxy Resin ◽  
Quantum Efficiency ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Rhodamine 6G ◽  
Energy Gap ◽  
Radiative Lifetime ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Absorption And Fluorescence Spectra

            The research is dealing with the absorption and fluorescence spectra for the hybrid of  an Epoxy Resin doped with organic dye Rhodamine (R6G) of different concentrations (5*10-6, 5*10-5, 1*10-5, 1*10-4, 5*10-4) Mol/ℓ at room temperature. The Quantum efficiency Qfm, the rate of fluorescence emission Kfm (s-1), the non-radiative lifetime τfm (s), fluorescence lifetime τf and the Stokes shift were calculated. Also the energy gap (Eg) for each dye concentration was evaluated. The results showed that the maximum quantum efficiency 62 % and maximum stokes shift 96 nm was obtained in dye concentration 5*10-6 and 1*10-4. The energy gap ranges between 1.066 eV to 1.128 eV depending proportionally on the dye concentrations.

Membranes affinity of 10-hydroxycamptothecin and SN-38, anticancer agents, determined by fluorescence spectra analysis

2006 ◽  
Author(s):  
Michał Cyrankiewicz ◽  
Blanka Ziomkowska ◽  
Stefan Kruszewski ◽  
Ryszard Siuda
Keyword(s):  
Anticancer Agents ◽  
Fluorescence Spectra ◽  
Spectra Analysis

Three-Dimensional Fluorescence Spectra Analysis of Oil Contaminants Based on Algorithm Combination Methodology

2019 ◽  
Vol 56 (3) ◽  
pp. 033002
Author(s):  
陈至坤 Chen Zhikun ◽  
黄微 Huang Wei ◽  
程朋飞 Cheng Pengfei ◽  
沈小伟 Shen Xiaowei ◽  
王福斌 Wang Fubin
Keyword(s):  
Fluorescence Spectra ◽  
Three Dimensional ◽  
Spectra Analysis

scholarly journals A Coumarin-Based Fluorescence Probe for Selective Recognition of Cu2+ Ions and Live Cell Imaging

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Guangjie He ◽  
Nana Ma ◽  
Linlin Li ◽  
Chenyan Xie ◽  
Linlin Yang ◽  
...  
Keyword(s):  
Live Cell Imaging ◽  
Density Functional ◽  
Fluorescence Probe ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Functional Theory ◽  
Photochemical Properties ◽  
Fluorescence Titrations

A new fluorescence probe L was rationally designed and synthesized for the recognition of Cu2+ ions by the combination of coumarin hydrazide and 2-acetylpyrazine. The photochemical properties and selectivity of L for Cu2+ ions in a CH3CN/HEPES (3 : 2, v/v) buffer were investigated by UV-vis absorption and fluorescence emission spectra. A highly selective and sensitive response of L for Cu2+ ions over other competing metal ions was observed with limit of detection in 3 μM. The coordination stoichiometry of L to Cu2+ ions was determined to be 1 : 1 by the UV-vis absorption spectrum, the fluorescence titrations, and density functional theory (DFT) calculations. Moreover, L was applied successfully for recognition of intracellular Cu2+ ions in living cells.

Fabrication and Characterization of LaOBr:Eu3+ Luminescent Nanofibers

2015 ◽  
Vol 1118 ◽  
pp. 92-96 ◽  
Author(s):  
Wen Sheng Yu ◽  
Chun Song Zhu ◽  
Qian Li Ma ◽  
Wen Wen Ma ◽  
Jin Xian Wang ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Fluorescence Spectra ◽  
Energy Levels ◽  
Energy Dispersion Spectroscopy ◽  
Spectra Analysis ◽  
Red Emission ◽  
X Ray ◽  
Double Crucible ◽  
Fabrication And Characterization

LaOBr:Eu3+ nanofibers have been successfully fabricated by electrospinning combined with a double-crucible bromination technique using cetyltrimethylammonium bromide (CTAB) powers as bromine source. The products were characterized in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS) and fluorescence spectroscopy. The results indicate that LaOBr:Eu3+ luminescent nanofibers are tetragonal in structure with space group P4/nmm. The diameter of LaOBr:Eu3+ luminescent nanofibers is ca. 150 nm. Fluorescence spectra analysis shows that under the excitation of 302-nm ultraviolet light, the LaOBr:Eu3+ nanofibers exhibit red emission centering at 620 nm, which is attributed to the 5D0→7F2 energy levels transitions of Eu3+ ions.

Facile synthesis of colloidal photoluminescent BiPO4:Ln (Eu,Tb) nanoparticles well-dispersed in polar solvents

CrystEngComm ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 278-282 ◽  
Author(s):  
Maozhan Huang ◽  
Zhou Xu ◽  
Cheng Hou ◽  
Hai-lang Jia ◽  
Jianhua Sun ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Facile Synthesis ◽  
Polar Solvents

Colloidal photoluminescence BiPO4:Ln (Eu,Tb) nanoparticles well-dispersed in polar solvents have been prepared, which exhibit organic-red and green colours under UV irradiation.

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