Femtosecond Intersystem Crossing to the Reactive Triplet State of the 2,6-Dithiopurine Skin Cancer Photosensitizer

2021 ◽  
Author(s):  
Luis A. Ortiz-Rodríguez ◽  
Sean J. Hoehn ◽  
Chris Acquah ◽  
Nadia Abbass ◽  
Lidia Waidmann ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Skin Cancer ◽  
Triplet State ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Strong Absorption ◽  
Intersystem Crossing ◽  
Ultraviolet A

Site-selected sulfur-substituted nucleobases are a class of all organic, heavy-atom-free photosensitizers for photodynamic therapy applications that exhibit excellent photophysical properties such as strong absorption in the ultraviolet-A region of the...

scholarly journals Twisted Bodipy Derivative: Intersystem Crossing, Electron Spin Polarization and Application As a Novel Photodynamic Therapy Reagent

2021 ◽  
Author(s):  
Yu Dong ◽  
Prashant Kumar ◽  
Partha Maity ◽  
Ivan Kurganskii ◽  
Shujing Li ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Quantum Yield ◽  
Triplet State ◽  
Spin Polarization ◽  
Electron Spin ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Electron Spin Polarization ◽  
Intersystem Crossing

The photophysical properties of a heavy atom-free Bodipy derivative with twisted π-conjugation framework were studied. Efficient intersystem crossing (ISC. Quantum yield: 56%) and exceptionally long-lived triplet state wereobserved (4.5 ms....

Löschung der Perylen-Fluoreszenz durch Ag+ -Ionen / Quenching of the Perylene Fluorescence by Ag+-Ions

1983 ◽  
Vol 38 (6) ◽  
pp. 698-700 ◽  
Author(s):  
H. Dreeskamp ◽  
A. Läufer ◽  
M. Zander
Keyword(s):  
Triplet State ◽  
Dynamic Process ◽  
Aromatic Compounds ◽  
Heavy Atom ◽  
Silver Ions ◽  
Intersystem Crossing ◽  
Fluid Solution ◽  
Long Wavelength ◽  
Wavelength Emission ◽  
Atom Effect

The fluorescence of perylene in fluid solution (λ0.0 = 440 nm) is quenched by silver ions in a dynamic process according to a Stern-Volmer kinetics (kq = 2 · 109 [1 • mol-1 · sec-1], in ethanol at 295 K). Simultaneously an unstructured long-wavelength emission (λmax ≈ 470 nm) appears which we assign to a perylene/Ag+ exciplex. A similar emission is observed when other polvcyclic aromatic compounds (PAC) are used, whose fluorescence as in the case of perylene is not easily quenched in an external heavy atom effect by iodopropane (kq ≦ 106). In these cases the excited PAC/Ag+ complex is long-lived enough to emit fluorescence since the intersystem crossing to the triplet system is slow due to the absence of an energetically favorable accepting triplet state

An exceptionally long-lived triplet state of red light-absorbing compact phenothiazine-styrylBodipy electron donor/acceptor dyads: a better alternative to the heavy atom-effect?

2020 ◽  
Vol 56 (11) ◽  
pp. 1721-1724 ◽  
Author(s):  
Yuqi Hou ◽  
Qingyun Liu ◽  
Jianzhang Zhao
Keyword(s):  
Charge Transfer ◽  
Triplet State ◽  
Electron Donor ◽  
Heavy Atom ◽  
Red Light ◽  
Intersystem Crossing ◽  
Spin Orbital ◽  
Heavy Atom Effect ◽  
Donor Acceptor ◽  
Atom Effect

Heavy atom-free dyads showing a red light-absorbing and exceptionally long-lived triplet state based on a spin–orbital charge transfer intersystem crossing mechanism.

scholarly journals Photophysical Properties of Pheophorbide-a Derivatives and Their Photodynamic Therapeutic Effects on a Tumor Cell LineIn Vitro

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Kang-Kyun Wang ◽  
Jing Li ◽  
Bong-Jin Kim ◽  
Jeong-Hyun Lee ◽  
Hee-Won Shin ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Triplet State ◽  
Singlet Oxygen ◽  
Alkyl Group ◽  
Photophysical Properties ◽  
Hydroxyl Group ◽  
Quantum Yields ◽  
Therapeutic Effects ◽  
Pheophorbide A

Pheophorbide-a derivatives have been reported to be potential photosensitizers for photodynamic therapy (PDT). In this study, photophysics of pheophorbide-a derivatives (PaDs) were investigated along with their photodynamic tumoricidal effectin vitro. PaDs were modified by changing the coil length and/or making the hydroxyl group (–OH) substitutions. Their photophysical properties were studied by steady-state and time-resolved spectroscopic methods. The photodynamic tumoricidal effect was evaluated in the mouse breast cancer cell line (EMT6). Lifetime and quantum yield of fluorescence and quantum yields of triplet state and singlet oxygen were studied to determine the dynamic energy flow. The coil length of the substituted alkyl group did not significantly affect the spectroscopic properties. However, the substitution with the hydroxyl group increased the quantum yields of the triplet state and the singlet oxygen due to the enhanced intersystem crossing. In order to check the application possibility as a photodynamic therapy agent, the PaDs with hydroxyl group were studied for the cellular affinity and the photodynamic tumoricidal effect of EMT6. The results showed that the cellular affinity and the photodynamic tumoricidal effect of PaDs with the hydroxyl group depended on the coil-length of the substituted alkyl group.

Excitation energies, singlet–triplet energy gaps, spin–orbit matrix elements and heavy atom effects in BOIMPYs as possible photosensitizers for photodynamic therapy: a computational investigation

2018 ◽  
Vol 20 (4) ◽  
pp. 2656-2661 ◽  
Author(s):  
Bruna Clara De Simone ◽  
Gloria Mazzone ◽  
Nino Russo ◽  
Emilia Sicilia ◽  
Marirosa Toscano
Keyword(s):  
Photodynamic Therapy ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Spin Orbit ◽  
Matrix Elements ◽  
Computational Investigation ◽  
Triplet Energy ◽  
Excitation Energies ◽  
Halogen Atoms ◽  
Energy Gaps

Introduction of halogen atoms in different amounts and positions into the BOIMPY skeleton significantly affects its photophysical properties.

scholarly journals Fluorescence properties of halogenated mono-hydroxyl corroles: the heavy-atom effects

2009 ◽  
Vol 13 (12) ◽  
pp. 1221-1226 ◽  
Author(s):  
Lei Shi ◽  
Hai-Yang Liu ◽  
Han Shen ◽  
Jun Hu ◽  
Guo-Liang Zhang ◽  
...  
Keyword(s):  
Fluorescence Spectra ◽  
Halogen Atom ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Phenyl Group ◽  
Atomic Weight ◽  
Quantum Yields ◽  
Intersystem Crossing ◽  
Fluorescence Quantum Yields ◽  
Atom Effect

A series of mono-hydroxyl corrole bearing a fluorine (1), chlorine (2), bromine (3) and iodine (4) atom on its 10-phenyl group have been synthesized. Fluorescence spectroscopy shows that the halogen atom at meso-phenyl group of corroles exhibit significant heavy-atom effect on their photophysical properties. Fluorescence quantum yields and the lifetime of these corroles decrease with the increasing of the atomic weight of halogen atoms. The quenching of the fluorescence could be interpreted in terms of a heavy atom-induced increase in intersystem crossing from S1 to T1. The intersystem crossing rate constant of these corroles were also determined by transient fluorescence spectra.

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