The chemical and photochemical properties of some 1,3-Diphenyl-2-pyrazolines

1974 ◽  
Vol 27 (10) ◽  
pp. 2267 ◽  
Author(s):  
NA Evans ◽  
DE Rivett ◽  
JFK Wilshire
Keyword(s):  
Singlet Oxygen ◽  
Photochemical Reaction ◽  
Heterocyclic Ring ◽  
Photo Oxidation ◽  
Effect Of Substituents ◽  
Effect Of Solvent ◽  
Fluorescence Efficiency ◽  
Photochemical Properties ◽  
The Stability

The effect of solvent and structure on the stability to light of a series of 1,3-diphenyl-2-pyrazolines has been studied. The major photochemical reaction observed is dehydrogenation to the corresponding 1,3-diphenylpyrazole unless the 5-position is disubstituted when, as in the case of 1,3,5,5-tetraphenyl-2- pyrazoline, photo-oxidation, with either retention or destruction of the heterocyclic ring, occurs. Evidence is presented that singlet oxygen may be involved in the photodehydrogenation of 1,3- diphenyl-2-pyrazoline. The observation that the presence of bulky groups in both the 4- and 5-positions improved both the fluorescence efficiency and the stability to light of the 1,3-diphenyl-2-pyrazoline molecule may have significance for the design of pyrazoline whitening agents. Dehydrogenation of the same series of pyrazolines with chloranil has been studied in order to determine the effect of substituents on the yield of pyrazole.

Light-induced Free Radical Oxidation of 2-Oxo-1,2,3,4-tetrahydropyrimidines

2012 ◽  
Vol 67 (3) ◽  
pp. 263-268
Author(s):  
Hamid Reza Memarian ◽  
Leila Hejazi ◽  
Asadallah Farhadi
Keyword(s):  
Benzoyl Peroxide ◽  
Free Radical Oxidation ◽  
Phenyl Group ◽  
Heterocyclic Ring ◽  
Radical Intermediate ◽  
Radical Oxidation ◽  
Photo Oxidation ◽  
Rate Determining Step ◽  
The Stability ◽  
Allylic Radical

A variety of 4-substituted 5-acetyl- and 5-carboethoxy-2-oxo-1,2,3,4-tetrahydropyrimidines were oxidized under UV irradiation in the presence or absence of benzoyl peroxide. The nature of the substituents on the 4- and 5-positions of the heterocyclic ring affects the rate of photo-oxidation, and irradiation of these compounds in the presence of benzoyl peroxide decreases the time of reaction drastically. Removal of 4-H by a benzoyloxy radical under formation of a trihydropyrimidinoyl radical intermediate occurs in the rate-determining step. The stability of this benzylic and allylic radical intermediate is affected by the nature and the position of the additional substituent on the phenyl group located at C-4.

scholarly journals Functionalization of Photosensitized Silica Nanoparticles for Advanced Photodynamic Therapy of Cancer

2021 ◽  
Vol 22 (12) ◽  
pp. 6618
Author(s):  
Ruth Prieto-Montero ◽  
Alejandro Prieto-Castañeda ◽  
Alberto Katsumiti ◽  
Miren P. Cajaraville ◽  
Antonia R. Agarrabeitia ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Absorption Capacity ◽  
Oxygen Production ◽  
Photodynamic Therapy Of Cancer ◽  
Custom Made ◽  
Fluorescence Efficiency ◽  
Covalently Linked

BODIPY dyes have recently attracted attention as potential photosensitizers. In this work, commercial and novel photosensitizers (PSs) based on BODIPY chromophores (haloBODIPYs and orthogonal dimers strategically designed with intense bands in the blue, green or red region of the visible spectra and high singlet oxygen production) were covalently linked to mesoporous silica nanoparticles (MSNs) further functionalized with PEG and folic acid (FA). MSNs approximately 50 nm in size with different functional groups were synthesized to allow multiple alternatives of PS-PEG-FA decoration of their external surface. Different combinations varying the type of PS (commercial Rose Bengal, Thionine and Chlorine e6 or custom-made BODIPY-based), the linkage design, and the length of PEG are detailed. All the nanosystems were physicochemically characterized (morphology, diameter, size distribution and PS loaded amount) and photophysically studied (absorption capacity, fluorescence efficiency, and singlet oxygen production) in suspension. For the most promising PS-PEG-FA silica nanoplatforms, the biocompatibility in dark conditions and the phototoxicity under suitable irradiation wavelengths (blue, green, or red) at regulated light doses (10–15 J/cm2) were compared with PSs free in solution in HeLa cells in vitro.

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.

scholarly journals Characteristics and Kinetics of Rosin Pentaerythritol Ester via Oxidation Process under Ultraviolet Irradiation

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2816 ◽  
Author(s):  
Yuanlin Li ◽  
Xiongmin Liu ◽  
Qiang Zhang ◽  
Bo Wang ◽  
Chang Yu ◽  
...  
Keyword(s):  
Light Intensity ◽  
Oxidation Kinetics ◽  
Pseudo First Order Reaction ◽  
Initial Oxidation ◽  
Photo Oxidation ◽  
Average Value ◽  
Pentaerythritol Ester ◽  
Fundamental Information ◽  
The Stability ◽  
Kinetics Of

A self-designed reaction device was used as a promising equipment to investigate the oxidation characteristics and kinetics of rosin pentaerythritol ester (RPE) under UV irradiation. Photo-oxidation kinetics and the initial quantum yield (Φ) of RPE were calculated. The initial oxidation product of the photo-oxidation reaction—peroxide was analyzed by iodimetry. The peroxide concentration is related to the light intensity (I) and the temperature (T), and the increasing T and I would destabilize the RPE by accelerating peroxide forming. Photo-oxidation of RPE follows the pseudo first-order reaction kinetics. The relationship between activation energy and logarithm of light intensity (ln I) is linear, and it is expressed as Ea = −4.937ln I + 45.565. Φ was calculated by the photo-oxidation kinetics, and the average value of Φ was 7.19% in the light intensity range of 200–800 μW cm−2. This research can provide fundamental information for application of RPE, and help obtain a better understanding of the stability of rosin esters.

Effect of solvent nature on the stability of highly dispersed and nanosized cadmium telluride

2013 ◽  
Vol 58 (10) ◽  
pp. 1166-1171 ◽  
Author(s):  
O. A. Kapush ◽  
L. I. Trishchuk ◽  
V. N. Tomashik ◽  
Z. F. Tomashik ◽  
S. D. Boruk
Keyword(s):  
Cadmium Telluride ◽  
Solvent Nature ◽  
Effect Of Solvent ◽  
Highly Dispersed ◽  
The Stability

The preparation and photochemical properties of some 1,3-Diphenyl-2-pyrazolines containing a heteroaromatic substituent

1977 ◽  
Vol 30 (3) ◽  
pp. 629 ◽  
Author(s):  
J Lin ◽  
DE Rivett ◽  
JFK Wilshire
Keyword(s):  
Photochemical Reaction ◽  
Large Scale ◽  
Polar Solvent ◽  
Methanolic Solution ◽  
Pyrazoline Ring ◽  
Photochemical Properties

Several 1,3-diphenyl- and 1,3,5-triphenyl-2-pyrazolines containing a heteroaromatic substituent (viz. imidazol-1-yl, pyrazol-1-yl and 1,2,4- triazol-1-yl) have been synthesized. When compared with their unsubstituted analogues, these compounds (a) absorbed more intensely at a longer wavelength, (b) exhibited greater fluorescence in a polar solvent (methanol) and (c) possessed similar stability to light. ��� Large-scale irradiations of two 1,3,5-triphenyl-2-pyrazolines (viz. unsubstituted and that containing the 1,2,4-triazol-1-yl substituent) in methanolic solution revealed that, although dehydrogenation of the 2-pyrazoline ring was the major photochemical reaction, significant oxidation to the corresponding chalcone also occurred. In addition, phenol was detected among the irradiation products. ��� Several sulphonated analogues of the abovementioned pyrazolines were prepared. When applied to wool, these compounds exhibited excellent fluorescent whitening properties.

New peripherally substituted lutetium mono and bis phthalocyanines: Synthesis and comparative photophysical and photochemical properties

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1542-1550
Author(s):  
Nagihan Kocaağa ◽  
Öznur Dülger Kutlu ◽  
Ali Erdoğmuş
Keyword(s):  
Mass Spectrometry ◽  
Photodynamic Therapy ◽  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Synthesis And Characterization ◽  
Type Ii ◽  
H Nmr ◽  
Photochemical Properties

In this study, the synthesis and characterization of mono-(phthalocyaninato) lutetium(III) (1-Cl and 1-F) [Lu[Formula: see text](AcO)(Pc)] (Pc [Formula: see text] phthalocyaninato, AcO [Formula: see text] acetate) and bis-(phthalocyaninato) lutetium(III) (2-Cl and 2-Br) [Lu[Formula: see text]Pc[Formula: see text]] bearing halogenated (F, Cl and Br) phenoxy–phenoxy groups are described and verified by IR, [Formula: see text]H-NMR, UV-vis and mass spectrometry. Photochemical and photophysical properties of 1-F, 1-Cl 2-Cl and 2-Br in DMSO are also presented. A comparison between photophysical and photochemical parameters of mono and bis derivatives showed that mono phthalocyanines are better photosensitizers than bis phthalocyanines. Photophysical and photochemical properties of phthalocyanines are very useful for photodynamic therapy applications. Singlet oxygen quantum yields [Formula: see text] give an indication of the potential of the complexes as photosensitizers in photodynamic therapy applications. The chloro, fluoro, bromo-phenoxy–phenoxy substituted mono-(phthalocyaninato) lutetium(III) complexes (1-Cl and 1-F) gave good singlet oxygen quantum yields (from 0.86 to 0.80) in DMSO. Thus, these complexes show potential as Type II photosensitizers for PDT of cancer.

scholarly journals Red and Near-Infrared Absorbing Dicyanomethylene Squaraine Cyanine Dyes: Photophysicochemical Properties and Anti-Tumor Photosensitizing Effects

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2083
Author(s):  
Tiago D. Martins ◽  
Eurico Lima ◽  
Renato E. Boto ◽  
Diana Ferreira ◽  
José R. Fernandes ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Near Infrared ◽  
Cyanine Dyes ◽  
Quantum Yields ◽  
Squaraine Dyes ◽  
Photodynamic Activity ◽  
Photochemical Properties ◽  
Radiation Treatments ◽  
Species Production

Photodynamic therapy is a medical modality developed for the treatment of several diseases of oncological and non-oncological etiology that requires the presence of a photosensitizer, light and molecular oxygen, which combined will trigger physicochemical reactions responsible for reactive oxygen species production. Given the scarcity of photosensitizers that exhibit desirable characteristics for its potential application in this therapeutic strategy, the main aims of this work were the study of the photophysical and photochemical properties and the photobiological activity of several dicyanomethylene squaraine cyanine dyes. Thus, herein, the study of their aggregation character, photobleaching and singlet oxygen production ability, and the further application of the previously synthesized dyes in Caco-2 and HepG2 cancer cell lines, to evaluate their phototherapeutic effects, are described. Dicyanomethylene squaraine dyes exhibited moderate light-stability and, despite the low singlet oxygen quantum yields, were a core of dyes that exhibited relevant in vitro photodynamic activity, as there was an evident increase in the toxicity of some of the tested dyes exclusive to radiation treatments.

Synthesis and characterization of novel 7-oxy-3-ethyl-6-hexyl-4-methylcoumarin substituted metallo phthalocyanines and investigation of their photophysical and photochemical properties

2019 ◽  
Vol 48 (34) ◽  
pp. 13046-13056 ◽  
Author(s):  
Mücahit Özdemir ◽  
Begümhan Karapınar ◽  
Bahattin Yalçın ◽  
Ümit Salan ◽  
Mahmut Durmuş ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Quantum Yields ◽  
Synthesis And Characterization ◽  
Photochemical Properties ◽  
Lipophilic Groups

Coumarin functionalized metallo phthalocyanines shows increased singlet oxygen quantum yields when included lipophilic groups.

scholarly journals Experimental and Theoretical Study of the Stability of the Complex Fisetin–Cu(II) and A Comparative Study of Free Ligand and Complex Interaction with Molecular Singlet Oxygen

2020 ◽  
Vol 96 (4) ◽  
pp. 815-825
Author(s):  
Vanesa A. Muñoz ◽  
Frida C. D. Dimarco Palencia ◽  
Matias I. Sancho ◽  
Sandra Miskoski ◽  
Norman A. García ◽  
...  
Keyword(s):  
Comparative Study ◽  
Singlet Oxygen ◽  
Theoretical Study ◽  
Free Ligand ◽  
Complex Interaction ◽  
The Stability ◽  
Molecular Singlet Oxygen
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