A photosensitizer with conformational restriction for enhanced photodynamic therapy

2021 ◽  
Author(s):  
Haiqiao Huang ◽  
Saran Long ◽  
Daipeng Huang ◽  
Jianjun Du ◽  
Jiangli Fan ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Triplet State ◽  
Quantum Yields ◽  
Fluorescence Lifetimes ◽  
Conformational Restriction ◽  
Fluorescence Quantum Yields ◽  
Flexible Molecule ◽  
Conformationally Restrained

A rigidly hemicyanine CSZ-J and a flexible molecule ESZ-J were synthesized. In particularly, the conformationally restrained CSZ-J had higher fluorescence quantum yields, longer fluorescence lifetimes and higher triplet state quantum...

Luminescence of 5-Phenyltetrazole and its Derivatives. Part II. Phosphorescence

1984 ◽  
Vol 39 (6) ◽  
pp. 556-559 ◽  
Author(s):  
I. Gryczyński ◽  
A. Kawski ◽  
Z. Grzonka ◽  
A. Rażyńska
Keyword(s):  
Triplet State ◽  
Quantum Yields ◽  
Intersystem Crossing ◽  
Thermal Deactivation ◽  
Fluorescence Quantum Yields ◽  
Radiative Transitions ◽  
Polyvinyl Alcohol Film ◽  
Methyl Derivatives ◽  
Temperature Responses ◽  
Phosphorescence Spectra

The phosphorescence spectra, mean lifetimes of phosphorescence and ratios of phosphorescence/ fluorescence quantum yields have been measured for 5-phenyltetrazole and its three methyl derivatives in a polyvinyl alcohol film over the temperature range of (77-250) K. Temperature responses of the non-radiative intersystem crossing constant. KST, and the non-radiative triplet state deactivation constant, km, have been investigated on the basis of these measurements. The energy of activation for the non-radiative transitions has been determined. With the methyl 5-phenyltetrazoles, the thermal deactivation of the triplet state, contrary to the intersystem crossing, has been found to be influenced by the position of the methyl substituent in the phenyl ring.

The influence of phenylethynyl linkers on the photo-physical properties of metal-free porphyrins

2000 ◽  
Vol 04 (07) ◽  
pp. 669-683 ◽  
Author(s):  
GARY A. BAKER ◽  
FRANK V. BRIGHT ◽  
MICHAEL R. DETTY ◽  
SIDDHARTH PANDEY ◽  
COREY E. STILTS ◽  
...  
Keyword(s):  
Excited State ◽  
Radiative Decay ◽  
Phenyl Group ◽  
Quantum Yields ◽  
Fluorescence Lifetimes ◽  
Strongly Coupled ◽  
Metal Free ◽  
Fluorescence Quantum Yields ◽  
Porphyrin Core ◽  
Absorbance Spectra

Series of 5,10,15,20-tetraarylporphyrins 1 and 5,10,15,20-tetrakis[4-(arylethynyl)phenyl]porphyrins 2 were prepared via condensation of pyrrole with the appropriate benzaldehyde or 4-(arylethynyl)benzaldehyde derivative (3). Condensation of meso-phenyldipyrromethane with mixtures of benzaldehyde and 4-(trimethylsilyl-ethynyl)benzaldehyde gave a separable mixture of mono- (6), bis- (both cis-7 and trans-8) and tris[4-(trimethylsilylethynyl)phenyl]porphyrin (9). Following removal of the trimethylsilyl groups of 6–9, the 4-ethynylphenyl groups of 11–14 were coupled to 1-iodo-3,5-di(trifluoromethyl)benzene with Pd ( OAc )2 to give 15–18 bearing one, two (both cis- and trans-) and three 4-[bis-3,5-(trifluoromethyl)phenylethynyl]phenyl groups respectively. Coupling of 11 and 1-iodo-4-nitrobenzene with Pd ( OAc )2 gave porphyrin 19 with one 4-(4-nitrophenylethynyl)phenyl group. Porphyrin 24 with a p-quinone linked to the porphyrin core via a phenylethynyl group was prepared via similar chemistry. The absorbance spectra, emission maxima, excited-state fluorescence lifetimes, quantum yields of fluorescence, rates of fluorescence and rates of non-radiative decay were measured for each of the porphyrins. Absorbance spectra and emission maxima were nearly identical for all the porphyrins of this study, which suggests that the aryl groups and 4-(arylethynyl)phenyl groups are not strongly coupled to the porphyrin core in these metal-free compounds. Fluorescence quantum yields and rates of radiative decay were larger for porphyrins bearing 4-(arylethynyl)phenyl groups, while excited-state fluorescence lifetimes were somewhat shorter. These effects were additive for each additional 4-(arylethynyl)phenyl group.

The observation of room temperature delayed fluorescence in various non-peripherally substituted phthalocyanines

2007 ◽  
Vol 11 (08) ◽  
pp. 613-617 ◽  
Author(s):  
Jannie C. Swarts ◽  
M. David Maree
Keyword(s):  
Room Temperature ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Fluorescence Lifetimes ◽  
Fluorescence Quantum Yields

The first observation of direct room temperature delayed fluorescence from non-peripherally substituted phthalocyanines is reported. The quantum yields of delayed fluorescence and delayed fluorescence lifetimes were determined and are discussed. The normal fluorescence quantum yields and photodegradative quantum yields of these compounds were also determined.

scholarly journals Utilizing selective chlorination to synthesize new triangulenium dyes

2021 ◽  
Author(s):  
Jesper Dahl Jensen ◽  
Niels Bisballe ◽  
Laura Kacenauskaite ◽  
Maria Storm Thomsen ◽  
Junsheng Chen ◽  
...  
Keyword(s):  
Early Stage ◽  
Quantum Yields ◽  
Electrophilic Aromatic Substitution ◽  
Fluorescence Lifetimes ◽  
Aromatic Substitution ◽  
Compound A ◽  
Fluorescence Quantum Yields ◽  
Reduction Potentials ◽  
Snar Reaction ◽  
High Fluorescence

Access to functionalization of new sites on the triangulenium core structure has been achieved at an early stage by chlorination with N-chlorosuccinimide (NCS), giving rise to two new triangulenium dyes (1 and 2). By introducing the chlorine functionalities in the acridinium precursor, positions complementary to those previously accessed by electrophilic aromatic substitution of the final dyes can be accesed. The chlorination is selective, giving only one regioisomer for both mono- and dichlorination products. For the monochlorinated acridinium compound a highly selective ring-closing reaction was discovered to generate only a single regioisomer of the cationic [4]helicene product. This discovery aspired further investigations into the mechanism of [4]helicene formation and to the first isolation of the previously proposed intermediate of the two-step SNAr reaction, key to all aza-bridged triangulenium and helicenium systems. A late stage functionalization of DAOTA+ with NCS gave rise to a different dichlorinated compound (2). The fully ring closed chlorinated triangulenium dyes 1, 2 and 3 show a redshift in absorption and emission relative to the non-chlorinated analogues, while still maintaining relatively high fluorescence quantum yields of 36%, 26%, and 41%, and long fluorescence lifetimes of 15 ns, 12.5 ns and 16 ns, respectively. Cyclic voltammetry shows that chlorination of the triangulenium dyes significantly lowers reduction potentials and thus allows for efficient tuning of redox and photo-redox properties.

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.

scholarly journals The origin of the solvent dependence of fluorescence quantum yields in dipolar merocyanine dyes

2019 ◽  
Vol 10 (48) ◽  
pp. 11013-11022 ◽  
Author(s):  
Joscha Hoche ◽  
Alexander Schulz ◽  
Lysanne Monika Dietrich ◽  
Alexander Humeniuk ◽  
Matthias Stolte ◽  
...  
Keyword(s):  
Activation Energy ◽  
Energy Barrier ◽  
Conical Intersection ◽  
Quantum Yields ◽  
Fluorescence Lifetimes ◽  
Activation Energy Barrier ◽  
Polar Solvents ◽  
Fluorescence Quantum Yields ◽  
Solvent Dependence ◽  
Merocyanine Dyes

An increasing activation energy barrier to a conical intersection was identified as the reason for higher fluorescence lifetimes and quantum yields for merocyanines in polar solvents.

Photophysical properties of Zn(II) phthalocyaninates incorporated into liposomes

2002 ◽  
Vol 06 (02) ◽  
pp. 122-129 ◽  
Author(s):  
Myriam E. Rodriguez ◽  
Josefina Awruch ◽  
Lelia Dicelio
Keyword(s):  
Photodynamic Therapy ◽  
Solid Tumor ◽  
Water Solubility ◽  
Photophysical Properties ◽  
Association Constants ◽  
The Other ◽  
Quantum Yields ◽  
Tumor Models ◽  
Fluorescence Quantum Yields ◽  
Cellular Components

Amphiphilic phthalocyanines are used as potential photosensitizers in photodynamic therapy. The low water solubility of most of these dyes is the reason that different kinds of vehicles are employed as endogenous carriers. Due to the photophysical inactivity of the phthalocyanine aggregates, it is important to improve their solubility in order to study dyes in solid tumor models. On the other hand, the photodynamic therapy activity depends on the location of phthalocyanines in the cell and the interaction of cellular components. In this work, the photophysical properties of tetrasubstituted Zn ( II ) phthalocyanines with different lipophilic properties are incorporated into liposomes of L-α-dimyristoylphosphatidylcholine (DMPC). The fluorescence quantum yields, the association constants and their localization in the membranes are reported.

Photochemical /Photocytotoxicity Studies of New Tetrapyrrolic Structures as Potential Candidates for Cancer Theranostics

2020 ◽  
Vol 17 (5) ◽  
pp. 661-669
Author(s):  
Luis F. Vieira Ferreira ◽  
Isabel Ferreira Machado ◽  
Ana Gama ◽  
Radu P. Socoteanu ◽  
Rica Boscencu ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Emission ◽  
Human Tumor ◽  
Phenyl Group ◽  
Quantum Yields ◽  
Integrating Sphere ◽  
Fluorescence Quantum Yields ◽  
Photodynamic Therapy Of Cancer ◽  
Cytotoxicity Studies ◽  
Absolute Measurements

Background: Detailed photochemical and photocytotoxicity studies of two new porphyrins: 5,10,15,20-meso-tetrakis-(4-acetoxy-3-methoxyphenyl) porphyrin (P2.1) and 5-(4-hydroxy-3- methoxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl)porphyrin (P2.2) are reported, as potential candidates for theranostics. For powdered samples of P2.1 and P2.2 adsorbed onto a powdered biocompatible substrate, polyethylene glycol (PEG), a concentration study was performed, correlating the fluorescence emission intensity with sample absorption to determine the useful concentration range for photodynamic therapy of cancer (PDT) in which aggregation does not occur. Cytotoxicity studies were performed in dark and illuminated conditions. Methods: The laser induced luminescence set-up is home-made, a N2 laser is used as the excitation source and a time gated charged-coupled device (ICCD) as the detector. Fluorescence lifetime determinations were made using pulsed light sources from the excitation LEDs and measures of the fluorescence intensities at different time delays after the excitation pulse. The singlet oxygen formation quantum yields ΦΔ measurements were obtained by comparing the total area of the emission spectra for the reference compound and also for the samples under study in the same solvent and with the same optical density at the excitation wavelength (405 nm). An integrating sphere for relative and absolute measurements was used in this work as an alternative methodology to obtain the values for the fluorescence emission quantum yields (ΦF) of the adsorbed porphyrin under study. The cytotoxicity evaluation was made in the dark and under irradiation, using four different human tumor cell lines and one non-tumor primary cell culture. Results: In order to establish the useful range of concentrations of the sensitizer for PDT, and due to the use of powdered samples, a special methodology was needed: the variations of the fluorescence lifetimes and fluorescence quantum yields were evaluated as a function of the concentration of the dye, measured by (1-R)*fdye. Both ΦF and τF are constant in the range from 0.002 to about 0.050 μmol g-1, and only after that a concentration quenching effect becomes visible, decreasing both ΦF and τF. This methodology is based in the correlations established between the Remission Function values and ΦF and τF obtained for increasing values of the sensitizer concentrations. Conclusion: The study of the aggregation effects of P2.1 and P2.2 porphyrins into a PEG matrix allowed us to determine the usable concentration range for photodynamic therapy use, where the aggregation of porphyrins decreases, therefore reducing the PDT action. The use of an integrating sphere for relative and absolute measurements of fluorescence quantum yields and also the lifetime studies as a function of the dye loading confirms the useful range for the use of P2.1 and P2.2 in PEG as powdered samples. The determination of the GI50, the porphyrin concentration which inhibits 50% of the cell growth, evidences that P2.2, the A3B porphyrin overtakes P2.1 (the A4 porphyrin) in terms of PDT efficiency and both porphyrins are much better PDT agents than the unsubstituted porphyrin, TPP. These data clearly show that porphyrins P2.2 and P2.1 exhibit an excellent behaviour in terms of its photocytotoxicity. These results encourage us to pursuit in the study of this family of porphyrins in which a balance of hydrophobic versus hydrophilic substituents in the phenyl group was achieved.

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.

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