Effect of intramolecular charge transfer on fluorescence and singlet oxygen production of phthalocyanine analogues

2012 ◽  
Vol 41 (38) ◽  
pp. 11651 ◽  
Author(s):  
Lenka Vachova ◽  
Veronika Novakova ◽  
Kamil Kopecky ◽  
Miroslav Miletin ◽  
Petr Zimcik
Keyword(s):  
Charge Transfer ◽  
Singlet Oxygen ◽  
Intramolecular Charge Transfer ◽  
Oxygen Production

Singlet Oxygen Production in Water:  Aggregation and Charge-Transfer Effects

1996 ◽  
Vol 100 (16) ◽  
pp. 6555-6560 ◽  
Author(s):  
Charles Tanielian ◽  
Christian Wolff ◽  
Marc Esch
Keyword(s):  
Charge Transfer ◽  
Singlet Oxygen ◽  
Oxygen Production ◽  
Transfer Effects

Influence of protonation of peripheral substituents on photophysical and photochemical properties of tetrapyrazinoporphyrazines

2010 ◽  
Vol 14 (07) ◽  
pp. 582-591 ◽  
Author(s):  
Veronika Novakova ◽  
Eva H. Mørkved ◽  
Miroslav Miletin ◽  
Petr Zimcik
Keyword(s):  
Charge Transfer ◽  
Sulfuric Acid ◽  
Singlet Oxygen ◽  
Electron Pair ◽  
Intramolecular Charge Transfer ◽  
Quantum Yields ◽  
Considerable Decrease ◽  
Fluorescence Quantum Yields ◽  
Photochemical Properties ◽  
Free Electron Pair

Octasubstituted zinc tetrapyrazinoporphyrazines with four N,N-dimethylaminophenyls and four phenyl or pyridin-3-yl substituents were synthesized and fully characterized. Their fluorescence quantum yields in DMF or pyridine were very low, almost undetectable, as a consequence of ultrafast intramolecular charge transfer. Titration of their DMF solutions with sulfuric acid led to increase of the fluorescence quantum yields by two orders of magnitude when the full protonation of peripheral substituents was achieved. Intramolecular charge transfer is no longer a favorable way of excited-state relaxation at full protonation of N,N-dimethylaminophenyl substituents because of loss of donor centers (free electron pair on its nitrogen). Similarly, singlet oxygen quantum yields also increased by two orders of magnitude when sulfuric acid was added to tetrapyrazinoporphyrazine solutions in DMF. Protonation at azomethine nitrogens of tetrapyrazinoporphyrazine macrocycle was observed at higher acid concentrations and it led to considerable decrease of fluorescence quantum yields. Octaphenyl zinc tetrapyrazinoporphyrazine and octa(pyridin-3-yl) zinc tetrapyrazinoporphyrazine were used as controls without intramolecular charge transfer. Their fluorescence and singlet oxygen quantum yields were high in DMF and decreased at higher concentrations of sulfuric acid due to protonation of azomethine nitrogens. The results suggest that the photophysical and photochemical properties of studied compounds may be controlled by changes of pH of medium.

Ultrafast intramolecular charge transfer in tetrapyrazinoporphyrazines controls the quantum yields of fluorescence and singlet oxygen

2010 ◽  
Vol 12 (11) ◽  
pp. 2555 ◽  
Author(s):  
Veronika Novakova ◽  
Petr Zimcik ◽  
Miroslav Miletin ◽  
Lenka Vachova ◽  
Kamil Kopecky ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Singlet Oxygen ◽  
Intramolecular Charge Transfer ◽  
Quantum Yields

Photophysics of Squaraine Dyes: Role of Charge-Transfer in Singlet Oxygen Production and Removal

2010 ◽  
Vol 114 (7) ◽  
pp. 2518-2525 ◽  
Author(s):  
Patrizio Salice ◽  
Jacob Arnbjerg ◽  
Brian Wett Pedersen ◽  
Rasmus Toftegaard ◽  
Luca Beverina ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Singlet Oxygen ◽  
Oxygen Production ◽  
Squaraine Dyes

Dynamic adjustment of emission from both singlets and triplets: the role of excited state conformation relaxation and charge transfer in phenothiazine derivates

2021 ◽  
Author(s):  
Weidong Qiu ◽  
Xinyi Cai ◽  
Mengke Li ◽  
Liangying Wang ◽  
Yanmei He ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dynamic Adjustment ◽  
Twisted Intramolecular Charge Transfer

Dynamic adjustment of emission behaviours by controlling the extent of twisted intramolecular charge transfer character in excited state.

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