scholarly journals The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

2012 ◽  
Vol 8 ◽  
pp. 1018-1026 ◽  
Author(s):  
Renjie Wang ◽  
Shouzhi Pu ◽  
Gang Liu ◽  
Shiqiang Cui
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Quantum Yields ◽  
Cyclic Voltammograms ◽  
Ortho Position ◽  
Formyl Group ◽  
Absorption Coefficients ◽  
Electrochemical Behaviors ◽  
Group Position ◽  
The One

Three new isomeric asymmetric diarylethenes with a naphthyl moiety and a formyl group at the para, meta or ortho position of the terminal benzene ring were synthesized. Their photochromism, fluorescent-switch, and electrochemical properties were investigated. Among these diarylethenes, the one with a formyl group at the ortho position of benzene displayed the largest molar absorption coefficients and fluorescence quantum yield. The cyclization quantum yields of these compounds increased in the order of para < ortho < meta, whereas their cycloreversion quantum yields decreased in the order of meta > para > ortho. Additionally, all of these diarylethenes functioned as effective fluorescent switches in both solution and PMMA films. Cyclic voltammograms proved that the formyl group and its position could effectively modulate the electrochemical behaviors of these diarylethene derivatives.

New soluble 4-(4-formyl-2,6-dimethoxyphenoxy) substituted phthalocyanines: Synthesis, characterization, photophysical and photochemical properties

2021 ◽  
pp. 1-10
Author(s):  
Ibrahim Erden ◽  
Betül Karadoğan ◽  
Fatma Aytan Kılıçarslan ◽  
Göknur Yaşa Atmaca ◽  
Ali Erdoğmuş
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
Fluorescence Quantum Yield ◽  
Metal Ion ◽  
Mass Spectra ◽  
Quantum Yields ◽  
Therapeutic Outcomes ◽  
Ft Ir ◽  
Photochemical Properties ◽  
New Compounds

This work describes the synthesis, spectral and fluorescence properties of bis 4-(4-formyl-2,6-dimethoxyphenoxy) substituted zinc (ZnPc) and magnesium (MgPc) phthalocyanines. The new compounds have been characterized by elemental analysis, UV-Vis, FT-IR, 1H-NMR and mass spectra. Afterward, the effects of including metal ion on the photophysicochemical properties of the complexes were studied in biocompatible solvent DMSO to analyze their potential to use as a photosensitizer in photodynamic therapy (PDT). The fluorescence and singlet oxygen quantum yields were calculated as 0.04–0.15 and 0.70–0.52 for ZnPc and MgPc, respectively. According to the results, MgPc has higher fluorescence quantum yield than ZnPc, while ZnPc has higher singlet oxygen quantum yield than MgPc. The results show that the synthesized complexes can have therapeutic outcomes for cancer treatment.

Terminology, relative photonic efficiencies and quantum yields in heterogeneous photocatalysis. Part II: Experimental determination of quantum yields

1999 ◽  
Vol 71 (2) ◽  
pp. 321-335 ◽  
Author(s):  
Angela Salinaro ◽  
Alexei V. Emeline ◽  
Jincai Zhao ◽  
Hisao Hidaka ◽  
Vladimir K. Ryabchuk ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Visible Region ◽  
Heterogeneous Photocatalysis ◽  
Quantum Yields ◽  
Yield Data ◽  
Normal Absorption ◽  
The One ◽  
Solid Liquid ◽  
Photonic Efficiency

In the preceding article [Serpone and Salinaro, Pure Appl. Chem., 71(2), 303-320 (1999)] we examined two principal features of heterogeneous photocatalysis that demanded scrutiny: (i) description of photocatalysis and (ii) description of process efficiencies. For the latter we proposed a protocol relative photonic efficiency which could subsequently be converted to quantum yields. A difficulty in expressing a quantum yield in heterogeneous photochemistry is the very nature of the system, either solid/liquid or solid/gas, which places severe restrictions on measurement of the photon flow absorbed by the light harvesting component, herein the photocatalyst TiO2, owing to non-negligible scattering by the particulates. It was imperative therefore to examine the extent of this problem. Extinction and absorption spectra of TiO2 dispersions were determined at low titania loadings by normal absorption spectroscopy and by an integrated sphere method, respectively, to assess the extent of light scattering. The method is compared to the one reported by Grela et al. [J. Phys. Chem., 100, 16940 (1996)] who used a polynomial extrapolation of the light scattered in the visible region into the UV region where TiO2 absorbs significantly. This extrapolation underestimates the scattering component present in the extinction spectra, and will no doubt affect the accuracy of the quantum yield data. Further, we report additional details in assessing limiting photonic efficiencies and quantum yields in heterogeneous photocatalysis.

Quantitative Determination of Photokinetic Parameters for Reversible Photoisomerizations in Light Scattering Adsorbent-Adsorbates

2000 ◽  
Vol 214 (2) ◽  
Author(s):  
R. Gade ◽  
Th. Porada
Keyword(s):  
Approximate Solution ◽  
Light Scattering ◽  
Quantum Yield ◽  
Present Method ◽  
Irradiation Time ◽  
Initial Slope ◽  
Quantum Yields ◽  
Absorption Coefficients ◽  
Actinic Light

Based on an approximate solution of the differential equations describing the rate of a reversible photoisomerization and the attenuation of the actinic light in a powdered adsorbent-adsorbate a method is presented permitting us to predict the irradiation time dependence of the sample reflectance and to determine both the quantum yields of the partial reactions and the absorption coefficients of the reactant and the product from the reflectance-time-curves measured at two different wavelengths. The present method, thus, is an improved version of the peviously reported procedure [1] which enables the quantum yield of a simple photoreaction to be calculated from the initial slope of the R(

Computational design of ratiometric two-photon fluorescent Zn2+ probes based on quinoline and di-2-picolylamine moieties

2021 ◽  
Author(s):  
Zhe Shao ◽  
Wen-Ying Zhang ◽  
Ke Zhao
Keyword(s):  
Quantum Yield ◽  
Cross Sections ◽  
Fluorescence Quantum Yield ◽  
Density Functional ◽  
Computational Design ◽  
Photon Absorption ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Two Photon ◽  
Before And After

Abstract To improve two-photon absorption (TPA) response of a newly synthesized probe, a series of ratiometric two-photon fluorescent Zn2+ sensors based on quinoline and DPA moieties have been designed. The one-photon absorption, TPA and emission properties of the experimental and designed probes before and after coordination with Zn2+ are investigated employing the density functional theory in combination with response functions. The design consists of two levels. In the first level of design, five probes are constructed through using several electron acceptors or donors to increase accepting or donating ability of the fluorophores. It shows that all the designed probes have stronger TPA intensities at longer wavelengths with respect to the experimental probe because of the increased intra-molecular charge transfer. Moreover, it is found that the probe 4 built by adding an acyl unit has the largest TPA cross section among the designed strictures due to the form of longer conjugated length and more linear backbone. One dimethylamino terminal attached along the skeleton can improve TPA intensity more efficiently than two side amino groups. Therefore, in the second level of design, a new probe 7 is formed by both an acyl unit and a dimethylamino terminal. It exhibits that the TPA cross sections of probe 7 and its zinc complex increase dramatically. Furthermore, the fluorescence quantum yields of the designed probes 4 and 7 are calculated in a new way, which makes use of the relation between the computed difference of dipole moment and the measured fluorescence quantum yield. The result shows that our design also improves the fluorescence quantum yield considerably. All in all, the designed probes 4 and 7 not only possess enhanced TPA intensities but also have large differences of emission wavelength upon Zn2+ coordination and strong fluorescence intensity, which demonstrates that they are potential ratiometric two-photon fluorescent probes.

scholarly journals Estimation of quantum yields of weak fluorescence from eosin Y dimers formed in aqueous solutions

2018 ◽  
Vol 17 (6) ◽  
pp. 793-799 ◽  
Author(s):  
Masami Enoki ◽  
Ryuzi Katoh
Keyword(s):  
Quantum Yield ◽  
Aqueous Solutions ◽  
Fluorescence Quantum Yield ◽  
Quantum Yields ◽  
Eosin Y

A weak fluorescence from eosin Y dimers can be observed. The fluorescence quantum yield was estimated to be 0.005.

Einfluß von Chlorsubstitution auf die El ektronenspektren von Biphenyl

1972 ◽  
Vol 27 (5) ◽  
pp. 756-759 ◽  
Author(s):  
H. Dreeskamp ◽  
O. Hutzinger ◽  
M. Zander
Keyword(s):  
Excited State ◽  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Emission Spectra ◽  
Liquid Solution ◽  
Quantum Yields ◽  
Decay Times ◽  
Fluorescence And Phosphorescence Spectra ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

Abstract Absorption spectra in liquid solution, fluorescence and phosphorescence spectra, phosphores-cence quantum yields, phosphorescence to fluorescence quantum yield ratios, and phosphorescence decay times of 9 chloro substituted biphenyls dissolved in low temperature EPA glass were in-vestigated. The emission spectra of sterically unhindered systems are structured and significantly Stokes-shifted. Ortho substitution shifts the conjugation band in absorption as well as the un-structured fluorescence and phosphorescence bands to shorter wave lengths presumably by pre-venting the system from attaining a planar excited state. Chloro substitution which increases the rate constant of phosphorescence in the order meta < para < ortho, is nearly additive for multiple substituted systems and is correlated to the MO coefficients at the chloro substituted position in the absence of steric hindrance

scholarly journals Сравнительные исследования фотофизических свойств димегина, фотодитазина и радахлорина

2019 ◽  
Vol 126 (2) ◽  
pp. 162
Author(s):  
И.В. Багров ◽  
А.В. Дадеко ◽  
В.М. Киселев ◽  
Т.Д. Муравьева ◽  
А.М. Стародубцев
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
Fluorescence Quantum Yield ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation

AbstractThe photophysical properties of three photosensitizers—dimegine, photoditazine, and radachlorin—have been comparatively examined. For dimegine and photoditazine, two techniques have been used to measure the singlet oxygen generation quantum yields and the quenching constants of singlet oxygen by dimegine and photoditazine, as well as the dimegine fluorescence quantum yield.

scholarly journals The morphologies and fluorescence quantum yields of perylene diimide dye-doped PS and PHVB microspheres

RSC Advances ◽  
2018 ◽  
Vol 8 (62) ◽  
pp. 35534-35538 ◽  
Author(s):  
Jia Chen ◽  
Shuoxun Jia ◽  
Xiaohuan Ji ◽  
Mohamed Nourrein ◽  
Hengxue Xiang ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Perylene Diimide ◽  
Quantum Yields ◽  
Polymer Microspheres ◽  
Polystyrene Microspheres ◽  
Fluorescence Quantum Yields

A POSS functionalized perylene diimide (PDI) derivative, PPP, is applied to polymer microspheres as a red fluorophore. Hollow PPP/polystyrene microspheres show a fluorescence quantum yield (ΦF) of nearly unity.

Red-emitting boron difluoride complexes with a mega-large Stokes shift and unexpectedly high fluorescence quantum yield

2020 ◽  
Vol 56 (14) ◽  
pp. 2159-2162 ◽  
Author(s):  
Xiaojie Ren ◽  
Fan Zhang ◽  
Hongchen Luo ◽  
Lide Liao ◽  
Xiangzhi Song ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Stokes Shift ◽  
Quantum Yields ◽  
Large Stokes Shift ◽  
Fluorescence Quantum Yields ◽  
Boron Difluoride ◽  
High Fluorescence ◽  
Stokes Shifts ◽  
High Fluorescence Quantum Yield

Introduction of a tetrahydroquinoxaline donor into boron difluoride complexes largely extended their emissions (617–684 nm), highly improved their fluorescence quantum yields (up to 0.68) and greatly increased their Stokes shifts (up to 209 nm).

Enhanced fluorescence quantum yield of syndiotactic side-chain TPE polymers via Rh-catalyzed carbene polymerization: influence of the substitution density and spacer length

2019 ◽  
Vol 10 (13) ◽  
pp. 1575-1584 ◽  
Author(s):  
Xiao Li ◽  
Yuhao Sun ◽  
Jian Chen ◽  
Zhongying Wu ◽  
Pin Cheng ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Quantum Yields ◽  
Side Chain ◽  
Enhanced Fluorescence ◽  
Spacer Length ◽  
Fluorescence Quantum Yields

The fluorescence quantum yields of the TPE-based C1 polymers also increase with the shortened spacer lengths and further improve by about 20% as compared with the corresponding C2 polyacrylate counterparts.

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