scholarly journals Effective Singlet Oxygen Sensitizers Based on the Phenazine Skeleton as Efficient Light Absorbers in Dye Photoinitiating Systems for Radical Polymerization of Acrylates

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3085
Author(s):  
Ilona Pyszka ◽  
Zdzisław Kucybała ◽  
Beata Jędrzejewska
Keyword(s):  
Quantum Yield ◽  
Visible Light ◽  
Triplet State ◽  
Singlet Oxygen ◽  
Radical Polymerization ◽  
State Formation ◽  
Flash Photolysis ◽  
Comparative Method ◽  
Aromatic Rings ◽  
Light Absorbers

A series of dyes based on the phenazine skeleton were synthesized. They differed in the number of conjugated double bonds, the arrangement of aromatic rings (linear and/or angular system), as well as the number and position of nitrogen atoms in the molecule. These compounds were investigated as potential singlet oxygen sensitizers and visible light absorbers in dye photoinitiating systems for radical polymerization. The quantum yield of the singlet oxygen formation was determined by the comparative method based on the 1H NMR spectra recorded for the tested dyes in the presence of 2,3-diphenyl-p-dioxene before and after irradiation. The quantum yield of the triplet state formation was estimated based on the transient absorption spectra recorded using the nanosecond flash photolysis technique. The effectiveness of the dye photoinitiating system was characterized by the initial rate of trimethylolpropane triacrylate (TMPTA) polymerization. In the investigated photoinitiating systems, the sensitizer was an electron acceptor, whereas the co-initiator was an electron donor. The effectiveness of TMPTA photoinitiated polymerization clearly depended on the arrangement of aromatic rings and the number of nitrogen atoms in the modified phenazine structure as well as the quantum yield of the triplet state formation of the photosensitizer in the visible light region.

Effect of Aggregation on Bacteriochlorin a Triplet-state Formation: A Laser Flash Photolysis Study¶

2002 ◽  
Vol 76 (5) ◽  
pp. 480 ◽  
Author(s):  
Xavier Damoiseau ◽  
Francis Tfibel ◽  
Maryse Hoebeke ◽  
Marie-Pierre Fontaine-Aupart
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash

scholarly journals Charge-transfer heptamethine dyes for NIR singlet oxygen generation

2019 ◽  
Vol 55 (38) ◽  
pp. 5511-5514 ◽  
Author(s):  
John B. Jarman ◽  
Dennis A. Dougherty
Keyword(s):  
Charge Transfer ◽  
Triplet State ◽  
Singlet Oxygen ◽  
State Formation ◽  
Charge Transfer State ◽  
Previous Evidence ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
A Charge ◽  
Transfer State

A heptamethine-based charge-transfer dye was designed based on previous evidence of triplet state formation in orthogonal charge-transfer partners and calculations suggesting the formation of a charge-transfer state in heptamethine dye derivatives.

Pulsed photoacoustic determination of the quantum yield of triplet state formation

1985 ◽  
Vol 30 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Stanisa̵w J. Komorowski ◽  
Zbigniew R. Grabowski ◽  
Wojciech Zielenkiewicz
Keyword(s):  
Quantum Yield ◽  
Triplet State ◽  
State Formation

Synthesis, photophysicochemical properties and TD-DFT calculations of tetrakis(2-benzoyl-4-chlorophenoxy) phthalocyanines

2014 ◽  
Vol 18 (04) ◽  
pp. 326-335 ◽  
Author(s):  
Yusuf Yılmaz ◽  
John Mack ◽  
M. Kasım Şener ◽  
Mehmet Sönmez ◽  
Tebello Nyokong
Keyword(s):  
Quantum Yield ◽  
Dft Calculations ◽  
Triplet State ◽  
Singlet Oxygen ◽  
Quantum Yields ◽  
Visible Absorption ◽  
H Nmr ◽  
Wide Range ◽  
Td Dft ◽  
The Impact

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.

Flash Photolysis and ESR Studies on Hematoporphyrin and Photofrin II in Polar and Microheterogeneous Environment

1989 ◽  
Vol 44 (4) ◽  
pp. 283-290 ◽  
Author(s):  
Raimund Quint ◽  
Ruth Maria Quint ◽  
Nikola Getoff ◽  
Tsvetan Gantchev ◽  
Maria Shopova
Keyword(s):  
Triplet State ◽  
Singlet Oxygen ◽  
Absorption Spectra ◽  
Flash Photolysis ◽  
Reducing Agent ◽  
Photodynamic Treatment ◽  
Photofrin Ii

Hematoporphyrin (HP) and its derivatives (HPD; e.g. photofrin II) are used as efficient sensitizers in the photodynamic treatment of tumors. The photoinduced formation of various transients resulting from these substrates at pH 12 and 7.4 were studied by conventional flash photolysis and by ESR techniques in the presence of various additives. EDTA is acting as an efficient reducing agent for the triplet state of the substrates. The absorption spectra of some transients (HP·-, HP -OH, HPD·-, HPD -OH) were obtained. Further, ESR studies (pH 4-7) showed that 3HP is mostly converted into HP·- - in the presence of EDTA, but this is not the case with 3HPD. In airfree HPD solutions a longlived transient was registered, which was attributed to HPD·+ species. In aerated substrate solutions the singlet oxygen ( 1O2) and peroxyradicals are formed. The discussed transients very likely are involved in the photodynamic treatment of tumors in man.

scholarly journals Phosphorescent oxygen-sensing and singlet oxygen production by a biosynthetic silk

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 39530-39533 ◽  
Author(s):  
Conor C. Horgan ◽  
Yong-Shen Han ◽  
Holly Trueman ◽  
Colin J. Jackson ◽  
Tara D. Sutherland ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Visible Light ◽  
Triplet State ◽  
Singlet Oxygen ◽  
Singlet State ◽  
Oxygen Sensing ◽  
Coiled Coil ◽  
Intersystem Crossing ◽  
Oxygen Production

A recombinant coiled-coil silk was utilised to immobilise heavy-metal-macrocycles which are known to undergo efficient intersystem crossing from the singlet state to the triplet state following excitation with visible light.

scholarly journals Quantifying Triplet State Formation in Zinc Dipyrrin Complexes

2019 ◽  
Author(s):  
Norah Z. Alqahtani ◽  
Toni G. Blevins ◽  
Catherine McCusker
Keyword(s):  
Quantum Yield ◽  
Triplet State ◽  
State Formation ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Transient Absorption Spectroscopy ◽  
Heavy Atoms ◽  
Earth Abundant ◽  
Photocatalytic Reactions

Photocatalysis is a promising method to harness solar energy and use it to form fuels and other high value chemicals, but most sensitizers used in photocatalytic reactions are complexes of rare and expensive metals such as ruthenium and iridium. Zinc dipyrromethene complexes have potential to be a more earth-abundant alternative, but their photophysical properties are largely unexplored. In this study, triplet state formation was quantified in two zinc dipyrromethene complexes, with a and without heavy atoms, by transient absorption spectroscopy. Without heavy atoms the triplet quantum yield was 16% in toluene and 27% in THF. With the addition of heavy I atoms the triplet quantum yield is increased to 62-63% and is insensitive to solvent polarity. These triplet yields meet or exceed those of successful organic photosensitizers, illustrating the potential for zinc dipyrromethene complexes as photosensitizers

Synthesis, photophysicochemical studies of adjacently tetrasubstituted binaphthalo-phthalocyanines

2005 ◽  
Vol 09 (05) ◽  
pp. 316-325 ◽  
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.

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