scholarly journals Broadband Visible Light-Absorbing [70]Fullerene-BODIPY-Triphenylamine Triad: Synthesis and Application as Heavy Atom-Free Organic Triplet Photosensitizer for Photooxidation

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1243
Author(s):  
San-E Zhu ◽  
Jian-Hui Zhang ◽  
Yu Gong ◽  
Li-Feng Dou ◽  
Li-Hua Mao ◽  
...  
Keyword(s):  
Excited State ◽  
Visible Light ◽  
Chemical Sensor ◽  
Heavy Atom ◽  
Visible Region ◽  
Intersystem Crossing ◽  
Triplet Excited State ◽  
Efficient Energy Transfer ◽  
Uv Visible ◽  
The Individual

A broadband visible light-absorbing [70]fullerene-BODIPY-triphenylamine triad (C70-B-T) has been synthesized and applied as a heavy atom-free organic triplet photosensitizer for photooxidation. By attaching two triphenylmethyl amine units (TPAs) to the π-core of BODIPY via ethynyl linkers, the absorption range of the antenna is extended to 700 nm with a peak at 600 nm. Thus, the absorption spectrum of C70-B-T almost covers the entire UV–visible region (270–700 nm). The photophysical processes are investigated by means of steady-state and transient spectroscopies. Upon photoexcitation at 339 nm, an efficient energy transfer (ET) from TPA to BODIPY occurs both in C70-B-T and B-T, resulting in the appearance of the BODIPY emission at 664 nm. Direct or indirect (via ET) excitation of the BODIPY-part of C70-B-T is followed by photoinduced ET from the antenna to C70, thus the singlet excited state of C70 (1C70*) is populated. Subsequently, the triplet excited state of C70 (3C70*) is produced via the intrinsic intersystem crossing of C70. The photooxidation ability of C70-B-T was studied using 1,5-dihydroxy naphthalene (DHN) as a chemical sensor. The photooxidation efficiency of C70-B-T is higher than that of the individual components of C70-1 and B-T, and even higher than that of methylene blue (MB). The photooxidation rate constant of C70-B-T is 1.47 and 1.51 times as that of C70-1 and MB, respectively. The results indicate that the C70-antenna systems can be used as another structure motif for a heavy atom-free organic triplet photosensitizer.

A fullerene-rhodamine B photosensitizer with pH-activated visible-light absorbance/fluorescence/photodynamic therapy

2018 ◽  
Vol 6 (18) ◽  
pp. 2778-2784 ◽  
Author(s):  
Qianyun Tang ◽  
Wanyue Xiao ◽  
Jiewei Li ◽  
Dapeng Chen ◽  
Yewei Zhang ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Excited State ◽  
Visible Light ◽  
Rhodamine B ◽  
Heavy Atom ◽  
Triplet Excited State ◽  
Turn On ◽  
State Generation ◽  
Fluorescence Turn On ◽  
Light Absorbance

A heavy-atom-free photosensitizer (C60-RB) with pH-activable visible-light absorbance enhancement, fluorescence turn-on and triplet excited state generation was designed for tumor bioimaging and photodynamic therapy.

Hydrothermal Synthesis of Nanosized Titania Photocatalysts Using Novel Water-Soluble Titanium Complexes

2007 ◽  
Vol 124-126 ◽  
pp. 723-726 ◽  
Author(s):  
Makoto Kobayashi ◽  
Koji Tomita ◽  
Valery Petrykin ◽  
Shu Yin ◽  
Tsugio Sato ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Single Phase ◽  
Visible Region ◽  
Water Soluble ◽  
No Oxidation ◽  
Nano Particles ◽  
Titanium Complexes ◽  
Uv Visible

Highly crystalline titania nano-particles were synthesized by hydrothermal method using novel stable water-soluble titanium complexes. It was confirmed that single phase anatase, rutile and brookite, which can be rarely synthesized as a single phase, can be obtained by varying the ligand in the complex and pH of the aqueous solution. TEM observations and BET specific surface area measurements had shown that these samples consisted of nanosized particles of 5~200 nm and had high specific surface areas of 25~150 m2/g. According to UV-visible diffuse reflectance spectra, these titania samples absorbed light in the visible region (λ > 400 nm). Photocatalytic activities in NO oxidation reaction exhibited by synthesized titania powders under the irradiation by UV- visible light were higher than the activity of the commercial TiO2 photocatalyst P25 (Degussa). Especially, under illumination by only visible light of above 510 nm wavelength, photocatalytic activity of the obtained specimens exceeded that of P25 more than four times. We also clearly demonstrated that single phase brookite had high photocatalytic activity for NO oxidation.

scholarly journals Preparation of Fe-DopedTiO2Nanotubes and Their Photocatalytic Activities under Visible Light

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang
Keyword(s):  
Visible Light ◽  
Visible Region ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Ultrasonic Assisted ◽  
Uv Visible

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.

The mechanism of the photochemical cycloaddition reaction of N-benzoylindole with cyclopentene

1990 ◽  
Vol 68 (10) ◽  
pp. 1685-1692 ◽  
Author(s):  
Bimsara W. Disanayaka ◽  
Alan C. Weedon
Keyword(s):  
Excited State ◽  
Quantum Yield ◽  
Ground State ◽  
Mechanistic Model ◽  
Cycloaddition Reaction ◽  
Intersystem Crossing ◽  
Triplet Excited State ◽  
Excited State Lifetime ◽  
Yield Data ◽  
Counting Procedure

The mechanism of the photochemical cycloaddition reaction between N-benzoylindole, 1, and cyclopentene to give cyclobutane adducts 2 and 3 has been examined. The triplet excited state lifetime and quantum yield of intersystem crossing were determined for 1 as (2.8 ± 0.3) × 10−8 s and 0.39 ± 0.01, respectively, using the triplet counting procedure. In addition, the dependence of the quantum yield of cycloadduct formation upon the concentration of cyclopentene and upon the concentration of excited state quenchers has been determined. The results are used to propose a mechanistic model in which the triplet excited state of 1 reacts with cyclopentene to give a triplet 1,4-biradical intermediate. Following spin inversion the biradical intermediate reverts to the ground state starting materials or proceeds to the products 2 and 3; this partitioning, along with the quantum yield of intersystem crossing, gives rise to a limiting quantum yield of cycloaddition at infinite alkene concentration of 0.061. It is calculated that 84% of the biradical intermediates revert to the starting materials and 16% proceed to cycloadducts. The quantum yield data are also used to calculate two independent values of the rate constant for reaction of the triplet excited 1 with alkene; the values are (1.8 ± 0.1) × 107M−1 s−1 and (4.0 ± 0.8) × 106 M−1 s−1'. Some evidence for self quenching of the triplet excited state of 1 by ground state 1 was also observed. The quantum yield of intersystem crossing and the triplet excited state lifetime of 1 were found to vary with the solvent used; this is discussed in terms of the possible existence of a charge transfer triplet excited state. Keywords: indole, photocycloaddition, mechanism.

Efficient intersystem crossing using singly halogenated carbomethoxyphenyl porphyrins measured using delayed fluorescence, chemical quenching, and singlet oxygen emission

2015 ◽  
Vol 17 (43) ◽  
pp. 29090-29096 ◽  
Author(s):  
Dawn M. Marin ◽  
Sonia Payerpaj ◽  
Graham S. Collier ◽  
Angy L. Ortiz ◽  
Gaurav Singh ◽  
...  
Keyword(s):  
Excited State ◽  
Singlet Oxygen ◽  
State Formation ◽  
Delayed Fluorescence ◽  
Intersystem Crossing ◽  
Fluorescence Lifetimes ◽  
Triplet Excited State

Singly halogenated carbomethoxyphenylporphyrins show decreased singlet fluorescence lifetimes and increased rates of triplet excited state formation.

Photoreactive Carbon and Nitrogen-Codoped ZnWO4 Nanoparticles: Synthesis and Reactivity

2012 ◽  
Vol 621 ◽  
pp. 172-177 ◽  
Author(s):  
Su Hua Chen ◽  
Bi Xuan Wang ◽  
Xian Hua Qiu ◽  
Zhen Sheng Xiong
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Region ◽  
Weight Ratio ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Carbon And Nitrogen ◽  
Uv Visible

In order to improve ZnWO4 photocatalytic activity under visible light, the C, N-codoped ZnWO4 nanoparticles have been successfully synthesized by choosing C3N4 generated from tripolycyanamide pyrolysis as the source of Carbon and Nitrogen and the influence of C3N4 concentration on structural, optical and morphological properties of C, N-codoped ZnWO4 using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM) and photocatalytic decoloration of rhodamine B (RhB) aqueous solution under visible light. It was found that the presence of carbon and nitrogen could not improve the crystallization of ZnWO4 species but could enhance their photoabsorption property in the visible region. The results also showed that the photocatalytic activity of the as-prepared ZnWO4 is higher than that of pure ZnWO4 with the optimum effect occurring at RC3N4 = 9 % (the weight ratio of tripolycyanamide to ZnWO4)

Excited State Dynamics of Novel Diporphyrins with Dissimilar Cores

1999 ◽  
Vol 03 (01) ◽  
pp. 70-77 ◽  
Author(s):  
M. RAVIKUMAR ◽  
R. P. PANDIAN ◽  
T. K. CHANDRASHEKAR
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Excitation Wavelength ◽  
Triplet Excited State ◽  
Lifetime Measurements ◽  
Time Resolved ◽  
Fluorescence Studies ◽  
Axial Ligation ◽  
Excitation Time ◽  
The Individual

The singlet and triplet excited state properties of two diporphyrins, H 2- H and Zn - H , are described. Steady state fluorescence studies indicate that the emission of the H 2- H diporphyrin is dependent on the excitation wavelength and is dominated by the emission of the individual constituent monomers at their respective excitation. Time-resolved studies show two lifetimes ascribable to the normal and thiaporphyrin subunits. However, the emission of the Zn - H diporphyrin is dominated by the thiaporphyrin subunit irrespective of the wavelength of excitation, suggesting an energy transfer from the Zn porphyrin subunit to the thiaporphyrin subunit. Lifetime measurements in toluene show two lifetimes due to open and folded conformations, while in DMF an additional component due to axial ligation is observed. The efficiency of energy transfer is moderately higher in DMF (72%) than in toluene (68%). Triplet ESR studies on the H 2- H dimer reveal a localized triplet with ZFS parameters and ESP pattern the same as for the individual monomers. On the other hand, triplet ESR of the Zn - H diporphyrin reveals triplet characteristics of the thiaporphyrin subunit, indicating an energy transfer in the triplet state.

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