scholarly journals Absorption Characteristics and Quantum Yields of Singlet Oxygen Generation of Thioguanosine Derivatives

2018 ◽  
Vol 94 (4) ◽  
pp. 677-684 ◽  
Author(s):  
Shoma Miyata ◽  
Takeshi Yamada ◽  
Tasuku Isozaki ◽  
Hideyuki Sugimura ◽  
Yao-Zhong Xu ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Quantum Yields ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Absorption Characteristics

Singlet oxygen generation of subphthalocyanine-fused dimer and trimer

2020 ◽  
Vol 24 (01n03) ◽  
pp. 211-219
Author(s):  
Rei Fujishiro ◽  
Hayato Sonoyama ◽  
Yuki Ide ◽  
Takuya Fujimura ◽  
Ryo Sasai ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Quantum Yields ◽  
Absorption Bands ◽  
Low Light ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Near Ir ◽  
Interesting Class ◽  
High Fluorescence ◽  
Significant Wavelength

Subphthalocyanine (SubPc) macrocycles are known as an interesting class of nonplanar aromatic dyes. Despite documented high fluorescence and singlet oxygen quantum yields, the properties of SubPcs in photodynamic therapy (PDT) are underestimated, because their absorption bands do not reach a significant wavelength range. With this in mind, we combined a SubPc ring and a SubPc ring by introducing a common benzene ring and obtained a SubPc dimer (2) and trimer (3) with the Q-band at the near-IR region, owing to the expansion of the [Formula: see text] electron conjugated system. In this study, we reported 1O2 generation abilities of 2 and 3based on the applied absolute singlet oxygen quantum yields ([Formula: see text]absolute). Subsequent research revealed that 2 and 3 showed the potential to generate 1O2 to not only in toluene but also in DMSO. Although the photocytotoxicity of 2 and 3 were investigated upon photo-irradiation with a low light dose of approximately 1.5 J/cm2, 2 and 3 showed almost negligible toxic properties toward HEp2 cells.

New heterogeneous photosensitizers with phthalocyanine molecules covalently linked to aminopropyl silica gel

2011 ◽  
Vol 15 (07n08) ◽  
pp. 718-726 ◽  
Author(s):  
Nina A. Kuznetsova ◽  
Olga A. Yuzhakova ◽  
Marina G. Strakhovskaya ◽  
Anna O. Shumarina ◽  
Anton S. Kozlov ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Silica Gel ◽  
Fluorescence Spectra ◽  
Quantum Yields ◽  
Absorption And Fluorescence Spectra ◽  
Oxygen Generation ◽  
E Coli ◽  
Singlet Oxygen Generation ◽  
Aqueous Suspensions ◽  
Covalently Linked

New heterogeneous photosensitizers were synthesized, in which phthalocyanines of zinc and aluminum, tetrasubstituted at non-peripheral positions with modified thiophenyl groups, were grafted to aminopropyl silica gel. The absorption and fluorescence spectra, and the quantum yields of fluorescence and photosensitized singlet oxygen generation were estimated for aqueous suspensions of these sensitizers. It is shown that upon photoexcitation, silica gel-bound phthalocyanines produce singlet oxygen and display photobactericidal activity against bacteria E. coli.

Bis-indole substituted phthalocyanines: Photophysical and photochemical properties

2020 ◽  
Vol 25 (01) ◽  
pp. 66-74
Author(s):  
Kevser Harmandar ◽  
Esra N. Kaya ◽  
Mehmet F. Saglam ◽  
Ibrahim F. Sengul ◽  
Devrim Atilla
Keyword(s):  
Photodynamic Therapy ◽  
Singlet Oxygen ◽  
Spectral Data ◽  
Quantum Yields ◽  
Oxygen Generation ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
Singlet Oxygen Generation ◽  
Photochemical Properties ◽  
C Nmr

Tetra substituted peripheral and non-peripheral Zn(II) phthalocyanines were successfully synthesized employing 4-(bis(3-methyl-1H-indol-2-yl)methyl)phenol as a starting material. The structure of these synthesized compounds was confirmed using 1H NMR, [Formula: see text]C NMR, infrared (IR), UV-vis, and MALDI-TOF spectral data. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation) properties of all synthesized peripheral and non-peripheral compounds were investigated in order to determine the potential of these compounds for application in photodynamic therapy.

A quantitative structure–property relationship (QSPR) study of singlet oxygen generation by pteridines

2016 ◽  
Vol 15 (6) ◽  
pp. 801-811 ◽  
Author(s):  
Andrey A. Buglak ◽  
Taisiya A. Telegina ◽  
Mikhail S. Kritsky
Keyword(s):  
Dipole Moment ◽  
Singlet Oxygen ◽  
Quantum Yields ◽  
Quantitative Structure ◽  
Oxygen Production ◽  
Structure Property ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Structure Property Relationship ◽  
Qspr Study

Singlet oxygen production quantum yields of pteridine photosensitizers were analyzed with the QSPR method. The ability of pterins and flavins to generate1O2in D2O correlated withEHOMOand electronegativity, as well as with the dipole moment and some other parameters.

Photochemical properties of substituted tetraazachlorins

2014 ◽  
Vol 18 (06) ◽  
pp. 457-464 ◽  
Author(s):  
Anton P. Lastovoy ◽  
Nina A. Kuznetsova ◽  
Ludmila K. Slivka ◽  
Elena A. Makarova
Keyword(s):  
Singlet Oxygen ◽  
Colloidal Solution ◽  
Quantum Yields ◽  
Aromatic Rings ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Micelle Core ◽  
Photodegradation Mechanism ◽  
Photochemical Properties ◽  
Aqueous Micellar Solutions

The photochemical properties of water-insoluble metal-free tetraazachlorin derivatives in organic solvents and aqueous micellar solutions of nonionic surfactants were investigated. The quantum yields of fluorescence, singlet oxygen generation and photodegradation were evaluated in benzene. The highest photostability and singlet oxygen quantum yield (ΦΔ = 0.7) was found for 2,2,3,3-tetramethyl-7,8,12,13,17,18-hexaphenyltetraazachlorin. The moderate ΦΔ values (0.21–0.35) of triarenotetraazachlorins in benzene were established. Expansion of tetraazachlorin π-system by fusion of three aromatic rings leads to reduction of efficiency of singlet oxygen generation. The study of photodegradation mechanism shows that radical photooxidation apparently is most plausible, though 1 O 2 may partly contribute to photodestruction of some tetraazachlorins. In aqueous colloidal solution of nonionic surfactant (Cremophor EL) the same, as in benzene, effect of sensitizer structure upon efficacy of singlet oxygen production was observed. It was shown that 1 O 2 diffusion from micelle core into solution and then to target slows its oxidation rate substantially in comparison to the case where sensitizer and target are localized in the same micelle.

Acid–base controllable singlet oxygen generation in supramolecular porphyrin–gold nanoparticle composites tethered by rotaxane linkers

2020 ◽  
Vol 24 (01n03) ◽  
pp. 171-180
Author(s):  
Akira Shinohara ◽  
Chengjun Pan ◽  
Lei Wang ◽  
Hideyuki Shinmori
Keyword(s):  
Singlet Oxygen ◽  
Gold Nanoparticle ◽  
Energy Transfer Efficiency ◽  
Quantum Yields ◽  
Free Base ◽  
Text Generation ◽  
Acid Base ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Nanoparticle Composites

Mechanically-interlocked photosensitizer–quencher systems based on free-base tetraphenylporphyrin (H2TPP)–gold nanoparticle (AuNP) composites has been designed and synthesized by utilizing a rotaxane architecture comprised of secondary ammonium and crown ether subunit. The H2TPP-substituted 24-crown-8 was able to shuttle along the alkanethiolate axle, triggered by deprotonation/protonation at the ammonium station, altering the H2TPP–AuNP distance and the photoexcitation energy transfer efficiency. Upon switching, quantum yields for photosensitized singlet oxygen (1O[Formula: see text] generation and fluorescence after deprotonation were quenched by 46% and 42%, respectively. External environment-responsive 1O2 generation based on such a protonation/deprotonation-driven molecular switch is potentially advantageous for a variety of applications including photodynamic therapies.

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 Quantitative Structure–property Relationship Modelling for the Prediction of Singlet Oxygen Generation by Heavy-Atom-Free BODIPY Photosensitizers

2021 ◽  
Author(s):  
Andrey A. Buglak ◽  
Asterios Charisiadis ◽  
Aimee Sheehan ◽  
Christopher J. Kingsbury ◽  
Mathias O.. Senge ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Quantum Chemical ◽  
Heavy Atom ◽  
Quantum Yields ◽  
Structure Property ◽  
Quantum Chemical Descriptors ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Structure Property Relationship ◽  
Chemical Descriptors

Heavy-atom-free sensitizers forming long-living triplet excited states via the spin-orbit charge transfer intersystem crossing (SOCT-ISC) process have recently attracted attention due to their potential to replace costly transition metal complexes in photonic applications. The efficiency of SOCT-ISC in BODIPY donor-acceptor dyads, so far the most thoroughly investigated class of such sensitizers, can be finely tuned by structural modification. However, predicting the triplet state yields and reactive oxygen species (ROS) generation quantum yields for such compounds in a particular solvent is still very challenging due to a lack of established quantitative structure-property relationship (QSPR) models. Herein, we analyzed the available data on singlet oxygen generation quantum yields (F?) for a dataset containing > 70 heavy-atom-free BODIPY in three different solvents (toluene, acetonitrile, and tetrahydrofuran). In order to build reliable QSPR model, we synthesized a series of new BODIPYs containing different electron donating aryl groups in the meso position, studied their optical and structural properties along with the solvent dependence of singlet oxygen generation, which confirmed the formation of triplet states via the SOCT-ISC mechanism. For the combined dataset of BODIPY structures, a total of more than 5000 quantum-chemical descriptors was calculated including quantum-chemical descriptors using Density Functional Theory (DFT), namely M06-2X functional. QSPR models predicting F? values were developed using multiple linear regression (MLR), which perform significantly better than other machine learning methods and show sufficient statistical parameters (R = 0.88 ? 0.91 and q2 = 0.62 ? 0.69) for all three solvents. A small root mean squared error of 8.2% was obtained for F? values predicted using MLR model in toluene. As a result, we proved that QSPR and machine learning techniques can be useful for predicting F? values in different media and virtual screening of new heavy-atom-free BODIPYs with improved photosensitizing ability.<br>

Symmetrical phthalocyanine bearing four triptycene moieties: Synthesis, photophysical and singlet oxygen generation

2019 ◽  
Vol 23 (09) ◽  
pp. 990-1000 ◽  
Author(s):  
Shaya Y. Al-Raqa ◽  
Bader S. Ghanem ◽  
Esra Nur Kaya ◽  
Mahmut Durmuş ◽  
Mohamed E. El-Khouly
Keyword(s):  
Singlet Oxygen ◽  
Chemical Method ◽  
Visible Region ◽  
Quantum Yields ◽  
Nanosecond Laser ◽  
Fluorescence Lifetimes ◽  
Absorption Bands ◽  
Oxygen Generation ◽  
Metal Free ◽  
Singlet Oxygen Generation

Novel metal-free (7) and zinc(II) (8) phthalocyanine derivatives bearing four substituted triptycene moieties were synthesized and fully characterized by various spectroscopic methods including 1H-NMR, 13C-NMR, mass, FT-IR and UV-vis. Photophysical and photochemical properties such as electronic absorption, fluorescence emission, fluorescence lifetimes and singlet oxygen generation were investigated in toluene. The UV-vis spectra of 7 and 8 exhibited absorption bands in the visible region. The fluorescence lifetimes of 7 and 8 phthalocyanines were found to be 6.2 and 3.6 ns, respectively. The ability of the examined zinc(II) (8) and metal-free (7) to produce the singlet oxygen has been determined by both chemical and direct methods. While the chemical method 1,3-diphenylisobenzofuran (DPBF) as a singlet oxygen quencher was used in the first method, the direct determination has been done by recording the weak emission band of the singlet oxygen in the near-infrared region (1270 nm). From the direct process, the quantum yields of the singlet oxygen were found to be 0.28 (for 7) and 0.60 (for 8) and similar values were also obtained by the chemical method. The fluorescence quenching behavior of the studied phthalocyanine compounds (8 and 7) by electron-accepting 1,4 benzoquinone (BQ) was also studied in toluene. The powerful nanosecond laser flash photolysis technique was also employed to record the transient absorption spectra of the long-lived triplet states of the investigated compounds.

Sign in / Sign up

Export Citation Format

Share Document