scholarly journals Generation of N,N-Di(4-bromophenyl)nitrenium Ion Under Acidic Conditions: Search for a Nitrenium Dication

2020 ◽  
Author(s):  
Andrea Zeppuhar ◽  
Daniel Falvey
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Cation Radical ◽  
Laser Flash ◽  
Strong Electron ◽  
Nitrenium Ion ◽  
Mechanistic Analysis ◽  
Separate Pathway ◽  
Acidic Conditions ◽  
Aqueous Conditions

The behavior of the N,N-di(4-bromophenyl)nitrenium ion under acidic aqueous conditions was examined via laser flash photolysis experiments. A long-lived species forms and can be assigned as the cation radical or the dication. This species is unreactive towards nucleophiles and reactive towards strong electron donors, consistent with a cation radical. Mechanistic analysis indicates its formation is through a separate pathway than that of the nitrenium ion, suggestive of a triplet mechanism.

scholarly journals Generation of N,N-Di(4-bromophenyl)nitrenium Ion Under Acidic Conditions: Search for a Nitrenium Dication

2020 ◽  
Author(s):  
Andrea Zeppuhar ◽  
Daniel Falvey
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Cation Radical ◽  
Laser Flash ◽  
Strong Electron ◽  
Nitrenium Ion ◽  
Mechanistic Analysis ◽  
Separate Pathway ◽  
Acidic Conditions ◽  
Aqueous Conditions

The behavior of the N,N-di(4-bromophenyl)nitrenium ion under acidic aqueous conditions was examined via laser flash photolysis experiments. A long-lived species forms and can be assigned as the cation radical or the dication. This species is unreactive towards nucleophiles and reactive towards strong electron donors, consistent with a cation radical. Mechanistic analysis indicates its formation is through a separate pathway than that of the nitrenium ion, suggestive of a triplet mechanism.

Substituted Phosphorous Triazatetrabenzocorroles: Correlation Between Structure and Excited State Properties

2009 ◽  
Vol 62 (5) ◽  
pp. 434 ◽  
Author(s):  
Xian-Fu Zhang ◽  
Yakuan Chang ◽  
Yanling Peng ◽  
Fushi Zhang
Keyword(s):  
Quantum Yield ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Photophysical Properties ◽  
Laser Flash ◽  
Time Resolved Fluorescence ◽  
Absorption Properties ◽  
Strong Electron ◽  
Time Resolved ◽  
Triplet Formation

The photophysical properties of five novel phthalocyanine analogues, dihydroxy phosphorus(v) triazatetrabenzocorrole (PTBC) substituted with –NO2, –SO3H, OiPr, and –NH2, respectively, were studied by a combination of absorption, steady-state emission, time-resolved fluorescence, and laser flash photolysis. All substituents, even for the strong electron-donating –NH2, cause only a slight red shift of their absorption and emission maxima. These complexes are generally monomeric in organic solution, whereas the sulfonated derivative, PTBC(SO3H)4, slightly aggregates in aqueous buffer. Distinct from phthalocyanines, PTBCs substituted with –NO2 or –NH2 still show high photo activities. The electron-withdrawing –NO2 and –SO3H decrease the fluorescence quantum yield but increase the triplet formation yield to 0.76 and 0.82, respectively. All PTBCs have long triplet lifetimes and hence generate singlet oxygen efficiently with a quantum yield from 0.43 to 0.75. Together with the ground-state absorption properties, the results suggest that these PTBCs may be used as excellent photosensitizers for photodynamic therapy.

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