scholarly journals New Acridone- and (Thio)Xanthone-Derived 1,1-Donor–Acceptor-Substituted Alkenes: pH-Dependent Fluorescence and Unusual Photooxygenation Properties

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3305
Author(s):  
Tim Lippold ◽  
Jörg M. Neudörfl ◽  
Axel Griesbeck
Keyword(s):  
Fluorescence Spectroscopy ◽  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Stokes Shift ◽  
Synthetic Route ◽  
Reactivity Pattern ◽  
Absorption And Fluorescence Spectroscopy ◽  
Donor Acceptor ◽  
Ph Dependent ◽  
Presence And Absence

A synthetic route to new heterocyclic 1,1-donor–acceptor-substituted alkenes starting with N-methyl-acridone, xanthone, and thioxanthone was investigated, leading to the acridone- and xanthone-derived products methyl 2-methoxy-2-(10-methylacridin-9 (10H)-ylidene)acetate (7) and methyl 2-methoxy-2-(9H-xanthen-9-ylidene)acetate (10) in low yields with the de-methoxylated product methyl 2-(10-methylacridin-9 (10H)-ylidene)acetate (8) and the reduced compound methyl 2-methoxy-2-(9H-xanthen-9-yl)acetate (11) as the major products from N-methyl acridone and xanthone. From thioxanthone, only the rearrangement and reduction products (14) and (15) resulted. The photophysical properties of compounds (7), (8), and (10) were investigated in the presence and absence of the Brønsted acid TFA by NMR, UV–VIS absorption, and fluorescence spectroscopy. Protonation of the acridone-derived alkenes (7) and (8) led to strong bathochromic and hyperchromic fluorescence shifts and a substantial increase in Stokes shift. The photooxygenation experiments with these substrates showed an unusual reactivity pattern in the singlet oxygen processes: whereas the electron-rich enolether (7) was chemically unreactive, (8) and (10) were oxidatively cleaved, presumably via intermediate 1,2-dioxetanes.

Assessment of the relevance of GaPc substituted with azido-polyethylene glycol chains for photodynamic therapy. Design, synthetic strategy, fluorescence, singlet oxygen generation, and pH-dependent spectroscopic behaviour

2017 ◽  
Vol 41 (18) ◽  
pp. 10027-10036 ◽  
Author(s):  
Veysel Koç ◽  
Sevinc Zehra Topal ◽  
Duygu Aydın Tekdaş ◽  
Özge Dilara Ateş ◽  
Emel Önal ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Polyethylene Glycol ◽  
Singlet Oxygen ◽  
Synthetic Route ◽  
Spectroscopic Behaviour ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Synthetic Strategy ◽  
Ph Dependent ◽  
Therapy Design

New synthetic route and PDT potential of symmetrically and asymmetrically substituted Ga(iii)Pcs with terminal azides.

Polypeptides with pendant porphyrins of defined sequence of chromophores: towards artificial photosynthetic systems

2008 ◽  
Vol 12 (12) ◽  
pp. 1232-1241 ◽  
Author(s):  
Farid Aziat ◽  
Régis Rein ◽  
Jorge Peón ◽  
Ernesto Rivera ◽  
Nathalie Solladié
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Amino Acid ◽  
Fluorescence Spectroscopy ◽  
Photophysical Properties ◽  
Free Base ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Absorption And Fluorescence Spectroscopy ◽  
Artificial Photosynthetic

In this paper we now report our ongoing progress in the preparation of artificial photosynthetic systems through the preparation of light harvesting multi-porphyrins. A tetramer, constituted of a central dipeptide functionalized by two free-base porphyrins and surrounded by one amino-acid bearing a pendant Zn ( II ) porphyrin on each side, has been chosen. The optical and photophysical properties of this tetramer have been studied by absorption and fluorescence spectroscopy. In addition, the energy transfer phenomenon has been studied and monitored by femtosecond time-resolved fluorescence. Our results indicate that the excited state dynamics redounding in the excitation being localized in the inner free-base porphyrins takes place in the time scale of approximately 1 ps.

scholarly journals Photophysical Properties of Donor-Acceptor Stenhouse Adducts and Their Inclusion Complexes with Cyclodextrins and Cucurbit[7]uril

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4928
Author(s):  
Liam Payne ◽  
Jason D. Josephson ◽  
R. Scott Murphy ◽  
Brian D. Wagner
Keyword(s):  
Aqueous Solution ◽  
Fluorescence Spectroscopy ◽  
Inclusion Complex ◽  
Charge Separation ◽  
Photophysical Properties ◽  
Protic Solvents ◽  
Mechanistic Insight ◽  
Donor Acceptor ◽  
Strong Inclusion ◽  
Supramolecular Complexation

Donor-acceptor Stenhouse adducts (DASAs) are a novel class of solvatochromic photoswitches with increasing importance in photochemistry. Known for their reversibility between open triene and closed cyclized states, these push-pull molecules are applicable in a suite of light-controlled applications. Recent works have sought to understand the DASA photoswitching mechanism and reactive state, as DASAs are vulnerable to irreversible “dark switching” in polar protic solvents. Despite the utility of fluorescence spectroscopy for providing information regarding the electronic structure of organic compounds and gaining mechanistic insight, there have been few studies of DASA fluorescence. Herein, we characterize various photophysical properties of two common DASAs based on Meldrum’s acid and dimethylbarbituric acid by fluorescence spectroscopy. This approach is applied in tandem with complexation by cyclodextrins and cucurbiturils to reveal the zwitterionic charge separation of these photoswitches in aqueous solution and the protective nature of supramolecular complexation against degradative dark switching. DASA-M, for example, was found to form a weak host-guest inclusion complex with (2-hydroxypropyl)-γ-cyclodextrin, with a binding constant K = 60 M−1, but a very strong inclusion complex with cucurbit[7]uril, with K = 27,000 M−1. This complexation within the host cavity was found to increase the half-life of both DASAs in aqueous solution, indicating the significant and potentially useful stabilization of these DASAs by host encapsulation.

scholarly journals Photophysical Properties of Protoporphyrin IX, Pyropheophorbide-a, and Photofrin® in Different Conditions

2021 ◽  
Vol 14 (2) ◽  
pp. 138
Author(s):  
Bauyrzhan Myrzakhmetov ◽  
Philippe Arnoux ◽  
Serge Mordon ◽  
Samir Acherar ◽  
Irina Tsoy ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Protoporphyrin Ix ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Visible Absorption ◽  
Light Dosimetry ◽  
Time Resolved ◽  
Pyropheophorbide A ◽  
Influence Of Solvent

Photodynamic therapy (PDT) is an innovative treatment of malignant or diseased tissues. The effectiveness of PDT depends on light dosimetry, oxygen availability, and properties of the photosensitizer (PS). Depending on the medium, photophysical properties of the PS can change leading to increase or decrease in fluorescence emission and formation of reactive oxygen species (ROS) especially singlet oxygen (1O2). In this study, the influence of solvent polarity, viscosity, concentration, temperature, and pH medium on the photophysical properties of protoporphyrin IX, pyropheophorbide-a, and Photofrin® were investigated by UV-visible absorption, fluorescence emission, singlet oxygen emission, and time-resolved fluorescence spectroscopies.

scholarly journals New Approach in the Application of Conjugated Polymers: The Light-Activated Source of Versatile Singlet Oxygen Molecule

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1098
Author(s):  
Agata Blacha-Grzechnik
Keyword(s):  
Conjugated Polymers ◽  
Singlet Oxygen ◽  
Near Infrared ◽  
Photophysical Properties ◽  
Short Review ◽  
The Novel ◽  
New Approach ◽  
Intermolecular Energy ◽  
Intermolecular Energy Transfer ◽  
High Absorption

For many years, the research on conjugated polymers (CPs) has been mainly focused on their application in organic electronics. Recent works, however, show that due to the unique optical and photophysical properties of CPs, such as high absorption in UV–Vis or even near-infrared (NIR) region and efficient intra-/intermolecular energy transfer, which can be relatively easily optimized, CPs can be considered as an effective light-activated source of versatile and highly reactive singlet oxygen for medical or catalytic use. The aim of this short review is to present the novel possibilities that lie dormant in those exceptional polymers with the extended system of π-conjugated bonds.

Synthesis, photophysical properties, and computational studies of benzothiadiazole and/or phenothiazine based donor/acceptor π-conjugated copolymers

2021 ◽  
Vol 28 (7) ◽  
Author(s):  
Ashraf A. El-Shehawy ◽  
Morad M. El-Hendawy ◽  
Adel M. Attia ◽  
Abdul-Rahman I. A. Abdallah ◽  
Nabiha I. Abdo
Keyword(s):  
Photophysical Properties ◽  
Computational Studies ◽  
Donor Acceptor ◽  
Conjugated Copolymers

Absorption and fluorescence spectroscopy on a smartphone

2015 ◽  
Author(s):  
Md. Arafat Hossain ◽  
John Canning ◽  
Kevin Cook ◽  
Sandra Ast ◽  
Peter J. Rutledge ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Absorption And Fluorescence Spectroscopy

Dual emissive bodipy–benzodithiophene–bodipy TICT triad with a remarkable Stokes shift of 194 nm

2018 ◽  
Vol 16 (12) ◽  
pp. 2033-2038 ◽  
Author(s):  
Sanchita Sengupta ◽  
Upendra K. Pandey
Keyword(s):  
Stokes Shift ◽  
High Mobility ◽  
Donor Acceptor

An acceptor–donor–acceptor (A–D–A) triad based on BODIPY and benzodithiophene exhibited a high Stokes shift of ∼194 nm, TICT and high mobility of 4.46 × 10−4 cm2 V−1 s−1.

Photophysical properties of aminomethylpsoralen in presence and absence of DNA

1980 ◽  
Vol 607 (2) ◽  
pp. 379-383 ◽  
Author(s):  
Christian Salet ◽  
Teresa Macedo De Sa E Melo ◽  
Rene Bensasson ◽  
Edward J. Land
Keyword(s):  
Photophysical Properties ◽  
Presence And Absence
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