Photoacoustic Measurements of Porphyrin Triplet-State Quantum Yields and Singlet-Oxygen Efficiencies

The synthesis of metal free, magnesium and zinc tetrakis(2-benzoyl-4-chlorophenoxy) phthalocyanine derivatives (2–4) is described along with their characterization by elemental analysis, IR, UV-visible absorption, and 1 H NMR spectroscopy and mass spectrometry. Trends observed in the fluorescence, triplet state, singlet oxygen and photodegradation quantum yields and the triplet state lifetimes are also analyzed. The compounds exhibit high solubility in a wide range of organic solvents and no evidence of aggregation was observed over a wide concentration range. The Zn ( II ) complex (4) was found to have a very high singlet oxygen quantum yield (ΦΔ = 0.78) in dimethylsulfoxide (DMSO) and a reasonably large triplet state quantum yield (ΦT = 0.82). The photophysical and photochemical properties clearly demonstrate that these compounds could prove useful in singlet oxygen applications such as photodynamic therapy (PDT). DFT and TD-DFT calculations were used to assess the impact of the positional isomerism of the 2-benzoyl-4-chlorophenoxy substituents on the electronic structures and optical spectroscopy.

Download Full-text

Synthesis, photophysicochemical studies of adjacently tetrasubstituted binaphthalo-phthalocyanines

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s108842460500040x ◽

2005 ◽

Vol 09 (05) ◽

pp. 316-325 ◽

Cited By ~ 7

Author(s):

Itumeleng Seotsanyana-Mokhosi ◽

Ji-Yao Chen ◽

Tebello Nyokong

Keyword(s):

Excited State ◽

Quantum Yield ◽

Triplet State ◽

Singlet Oxygen ◽

Photophysical Properties ◽

Zinc Phthalocyanine ◽

Quantum Yields ◽

Triplet Excited State ◽

General Increase ◽

Photochemical Behavior

Adjacent binaphthalo-phthalocyanines tetra-substituted with phenoxy (4a), 4-carboxyphenoxy (4b) and 4-t-butylphenoxy (4c) groups, as well as the di-substituted 4-carboxyphenoxy (5b) have been synthesized and characterized. The photophysical and photochemical behavior of 4a-c, were compared with those of the corresponding di-substituted derivatives, (5a-c). The secondary substituents on the phenoxy ring have an influence on the aggregation of the molecules and hence on their photophysical properties. All of the complexes exhibit a relatively good conversion of energy from the triplet-excited state to the singlet oxygen. The less aggregated molecule (4c), has the highest singlet oxygen quantum yield. For all the molecules, fluorescence yields are low and they all have relatively shorter triplet lifetimes compared with the unsubstituted zinc phthalocyanine. Increasing the number of ring substituents on these rigid MPc complexes (from complexes 5 to 4) showed a general increase in the triplet state lifetimes and singlet oxygen quantum yields, and a decrease in stability.

Download Full-text

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

International Journal of Photoenergy ◽

10.1155/2014/793723 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 2

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.

Download Full-text

Products of Docosahexaenoate Oxidation as Contributors to Photosensitising Properties of Retinal Lipofuscin

International Journal of Molecular Sciences ◽

10.3390/ijms22073525 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3525

Author(s):

Małgorzata B. Różanowska ◽

Anna Pawlak ◽

Bartosz Różanowski

Keyword(s):

Visible Light ◽

Triplet State ◽

Singlet Oxygen ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Wavelength Dependence ◽

Oxidation Products ◽

Quantum Yields ◽

Excited Triplet ◽

Uva Light

Retinal lipofuscin which accumulates with age in the retinal pigment epithelium (RPE) is subjected to daily exposures to high fluxes of visible light and exhibits potent photosensitising properties; however, the molecules responsible for its photoreactivity remain unknown. Here, we demonstrate that autooxidation of docosahexaenoate (DHE) leads to the formation of products absorbing, in addition to UVB and UVA light, also visible light. The products of DHE oxidation exhibit potent photosensitising properties similar to photosensitising properties of lipofuscin, including generation of an excited triplet state with similar characteristics as the lipofuscin triplet state, and photosensitised formation of singlet oxygen and superoxide. The quantum yields of singlet oxygen and superoxide generation by oxidised DHE photoexcited with visible light are 2.4- and 3.6-fold higher, respectively, than for lipofuscin, which is consistent with the fact that lipofuscin contains some chromophores which do contribute to the absorption of light but not so much to its photosensitising properties. Importantly, the wavelength dependence of photooxidation induced by DHE oxidation products normalised to equal numbers of incident photons is also similar to that of lipofuscin—it steeply increases with decreasing wavelength. Altogether, our results demonstrate that products of DHE oxidation include potent photosensitiser(s) which are likely to contribute to lipofuscin photoreactivity.

Download Full-text

Synthesis and Biological Evaluations of Organoruthenium Scaffolds: A Comprehensive Update

Current Organic Synthesis ◽

10.2174/1570179414666170703143049 ◽

2018 ◽

Vol 15 (2) ◽

pp. 179-207

Author(s):

Ashaparna Mondal ◽

Priyankar Paira

Keyword(s):

Singlet Oxygen ◽

Anticancer Agents ◽

Ruthenium Complexes ◽

Chemotherapeutic Agents ◽

Quantum Yields ◽

Ros Generation ◽

Standard Drug ◽

Cellular Environment ◽

Theranostic Agents

Background: Currently ruthenium complexes are immerging as effective anticancer agents due to their less toxicity, better antiproliferative and antimetastatic activity, better stability in cellular environment and most importantly variable oxidation and co-ordination states of ruthenium allows binding this molecule with a variety of ligands. So in past few years researchers have shifted their interest towards organoruthenium complexes having good fluorescent profile that may be applicable for cancer theranostics. Nowadays, photodynamic therapy has become more acceptable because of its easy and effective approach towards killing cancer cells. Objective: Objective of this review article is to shed light on synthesis, characterization, stability and fluorescence studies of various ruthenium [Ru(II) and Ru(III)] complexes and different bioactivity studies conducted with the synthesized compounds to test their candidacy as potent chemotherapeutic agents. Methods: Various heterocyclic ligands containing N,O and S as heteroatom mainly were prepared and subjected to complexation with ruthenium-p-cymene moiety. In most cases [Ru(η6-p-cymene)(µ-Cl)Cl]2 was used as ruthenium precursor and the reactions were conducted in various alcohol medium such as methanol, ethanol or propanol. The synthesized complexes were characterized by 1H NMR and 13C NMR spectroscopy, GC-MS, ESI-MS, elemental analysis and single crystal X-ray crystallography methods. Fluorescence study and stability study were conducted accordingly using water, PBS buffer or DMSO. Stable compounds were considered for cell viability studies. To study the efficacy of the compounds in ROS generation as photosensitizers, in few cases, singlet oxygen quantum yields in presence of light were calculated. Suitable compounds were selected for in vitro & in vivo antiproliferative, anti-invasive activity studies. Result: Many newly synthesized compounds were found to have less IC50 compared to a standard drug cysplatin. Those compounds were also stable preferably in physiological conditions. Good fluorescence profile and ROS generation ability were observed for few compounds. Conclusion: Numerous ruthenium complexes were developed which can be used as cancer theranostic agents. Few molecules were synthesized as photosensitizers which were supposed to generate reactive singlet oxygen species in targeted cellular environment in presence of a particular type of light and thereby ceasing cancer cell growth.

Download Full-text

Ruthenium-based PACT agents based on bisquinoline chelates: synthesis, photochemistry, and cytotoxicity

JBIC Journal of Biological Inorganic Chemistry ◽

10.1007/s00775-021-01882-8 ◽

2021 ◽

Author(s):

Anja Busemann ◽

Ingrid Flaspohler ◽

Xue-Quan Zhou ◽

Claudia Schmidt ◽

Sina K. Goetzfried ◽

...

Keyword(s):

Quantum Yield ◽

Singlet Oxygen ◽

Cancer Cells ◽

Cellular Uptake ◽

Ruthenium Complex ◽

Human Cancer ◽

Light Irradiation ◽

Quantum Yields ◽

Light Activation ◽

Human Cancer Cells

AbstractThe known ruthenium complex [Ru(tpy)(bpy)(Hmte)](PF6)2 ([1](PF6)2, where tpy = 2,2’:6’,2″-terpyridine, bpy = 2,2’-bipyridine, Hmte = 2-(methylthio)ethanol) is photosubstitutionally active but non-toxic to cancer cells even upon light irradiation. In this work, the two analogs complexes [Ru(tpy)(NN)(Hmte)](PF6)2, where NN = 3,3'-biisoquinoline (i-biq, [2](PF6)2) and di(isoquinolin-3-yl)amine (i-Hdiqa, [3](PF6)2), were synthesized and their photochemistry and phototoxicity evaluated to assess their suitability as photoactivated chemotherapy (PACT) agents. The increase of the aromatic surface of [2](PF6)2 and [3](PF6)2, compared to [1](PF6)2, leads to higher lipophilicity and higher cellular uptake for the former complexes. Such improved uptake is directly correlated to the cytotoxicity of these compounds in the dark: while [2](PF6)2 and [3](PF6)2 showed low EC50 values in human cancer cells, [1](PF6)2 is not cytotoxic due to poor cellular uptake. While stable in the dark, all complexes substituted the protecting thioether ligand upon light irradiation (520 nm), with the highest photosubstitution quantum yield found for [3](PF6)2 (Φ[3] = 0.070). Compounds [2](PF6)2 and [3](PF6)2 were found both more cytotoxic after light activation than in the dark, with a photo index of 4. Considering the very low singlet oxygen quantum yields of these compounds, and the lack of cytotoxicity of the photoreleased Hmte thioether ligand, it can be concluded that the toxicity observed after light activation is due to the photoreleased aqua complexes [Ru(tpy)(NN)(OH2)]2+, and thus that [2](PF6)2 and [3](PF6)2 are promising PACT candidates. Graphic abstract

Download Full-text

Merbromin (mercurochrome) and other xanthene dyes: Quantum yields of triplet sensitizer generation and singlet oxygen formation in alcoholic solutions

Journal of Photochemistry and Photobiology B Biology ◽

10.1016/1011-1344(92)85018-p ◽

1992 ◽

Vol 12 (1) ◽

pp. 57-81 ◽

Cited By ~ 18

Author(s):

Klaus Gollnick ◽

Theodor Franken ◽

Mohamed F.R. Fouda ◽

Hanns R. Paur ◽

Stephan Held

Keyword(s):

Singlet Oxygen ◽

Quantum Yields ◽

Xanthene Dyes ◽

Oxygen Formation ◽

Singlet Oxygen Formation

Download Full-text

New soluble 4-(4-formyl-2,6-dimethoxyphenoxy) substituted phthalocyanines: Synthesis, characterization, photophysical and photochemical properties

Main Group Chemistry ◽

10.3233/mgc-210123 ◽

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.

Download Full-text