Effects of Chlorophyll Triplet States on the Kinetics of Spectral Hole Growth

2021 ◽  
Vol 125 (13) ◽  
pp. 3278-3285
Author(s):  
Alexandra Trempe ◽  
Alexander Levenberg ◽  
Angel David Gonzalez Ortega ◽  
Maria A. Lujan ◽  
Rafael Picorel ◽  
...  
Keyword(s):  
Triplet States ◽  
Spectral Hole ◽  
Hole Growth ◽  
Kinetics Of

Protonation of some non-transition metal phthalocyanines — spectral and photophysicochemical consequences

2012 ◽  
Vol 16 (07n08) ◽  
pp. 885-894 ◽  
Author(s):  
Abimbola O. Ogunsipe ◽  
Mopelola A. Idowu ◽  
Taofeek B. Ogunbayo ◽  
Isaac A. Akinbulu
Keyword(s):  
Transition Metal ◽  
Rate Constant ◽  
Rate Equation ◽  
Aluminum Chloride ◽  
Ground State ◽  
Triplet States ◽  
Metal Phthalocyanines ◽  
Excited Triplet ◽  
Kinetics Of ◽  
Excited Triplet States

The photophysics and photochemistry of phthalocyanine complexes of magnesium (MgPc), aluminum chloride (ClAlPc) and zinc (ZnPc) are studied in N,N′-dimethylformamide (DMF). The values obtained for the photophysical and photochemical parameters are normal for simple metallophthalocyanine (MPc) complexes. Protonation of the azomethine bridges reduced the photoactivities of the complexes considerably; however the excited triplet states of the protonated species are more stable towards ground state oxygen. The interaction of the non-protonated MPcs with ground state oxygen is shown to be diffusion-assisted, with bimolecular rate constant values of the order of 1010 M-1.s-1. MgPc could not be protonated; it was easily demetalated by the protonating acid. The kinetics of the demetalation yielded the rate equation: Rate = 0.1[MgPc][H+]2/3

Photophysical and Photochemical Properties of Some Fluorescent Derivatives of Vitamin B1

1987 ◽  
Vol 42 (5) ◽  
pp. 485-489 ◽  
Author(s):  
B. Marciniak
Keyword(s):  
Vitamin B1 ◽  
Emission Spectra ◽  
Photochemical Reactions ◽  
Triplet States ◽  
Excited Singlet ◽  
Yield Data ◽  
Singlet And Triplet States ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Fluorescent Derivatives

Absorption and emission spectra, depopulation kinetics of the lowest excited singlet and triplet states and acid-base equilibria of two fluorescent vitamin B, derivatives, the products I and II of the reaction of N-methylated vitamine B, with cytidine and adenosine, respectively, were investigated. Analysis of the lifetime and quantum yield data indicate that at 77 K emissions are the main processes of deactivation of the S1 and T1 states for the free ion and protonated forms. The pKa values indicate a much higher acidity in the excited singlet and triplet states than in the ground state. I and II undergo very slow photochemical reactions in solution in the presence of oxygen (Φ ~ 10-4).

Sign in / Sign up

Export Citation Format

Share Document