Electronic absorption, MCD, and luminescence properties of porphyrin J-aggregates

2013 ◽  
Vol 17 (08n09) ◽  
pp. 703-711 ◽  
Author(s):  
Yuichi Kitagawa ◽  
Junji Hiromoto ◽  
Kazuyuki Ishii
Keyword(s):  
Electronic Absorption ◽  
Magnetic Circular Dichroism ◽  
Protonated Form ◽  
Red Shift ◽  
Energy Splitting ◽  
Absorption Bands ◽  
Exciton Interactions ◽  
J Aggregates ◽  
Fluorescence And Phosphorescence Spectra ◽  
Phosphorescence Spectra

In this paper, we have investigated electronic absorption, magnetic circular dichroism, fluorescence, and phosphorescence spectra for a protonated form of H 2 TPPS 4( H 4 TPPS 4) and the J-aggregates of H 4 TPPS 4. The J-aggregation induces a large red-shift in the B (Soret) and Q absorption bands, while the phosphorescence peaks of H 4 TPPS 4 and its J-aggregates are almost entirely similar. The large red-shift of the B-band is quantitatively explained by the exciton interactions. Thus, the exciton interactions in the J-aggregates are proposed as a useful approach to decrease the energy splitting between the fluorescent and phosphorescent states.

scholarly journals Natural and magnetic circular dichroism spectra of nucleosides: effect of the dynamics and environment

RSC Advances ◽  
2021 ◽  
Vol 11 (14) ◽  
pp. 8411-8419
Author(s):  
Jakub Kaminský ◽  
Valery Andrushchenko ◽  
Petr Bouř
Keyword(s):  
Molecular Dynamics ◽  
Circular Dichroism ◽  
Nucleic Acids ◽  
Electronic Absorption ◽  
Magnetic Circular Dichroism ◽  
Circular Dichroism Spectra ◽  
Circular Dichroïsm ◽  
Magnetic Circular Dichroism Spectra

Electronic absorption, natural and magnetic circular dichroism spectra of several nucleosides are simulated to understand their dependence on molecular dynamics and environment, their sensitivity to nucleoside pairing and stacking in nucleic acids.

Investigation of Spectral Sensitization III. A Study of the Visible and Infrared Spectra of Some Very Pure Bis-Thiazolinyl and Bis-Thiazolyl Cyanine Iodides

1966 ◽  
Vol 20 (3) ◽  
pp. 150-158 ◽  
Author(s):  
A. Leifer ◽  
M. Boedner ◽  
P. Dougherty ◽  
A. Fusco ◽  
M. Koral ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Low Frequency ◽  
Red Shift ◽  
Absorption Bands ◽  
Spin Resonance ◽  
Visible Spectra ◽  
Bond System ◽  
Phenyl Rings ◽  
In Series ◽  
Systematic Group

A detailed study of the visible spectra in solution and the infrared spectra of the dyes in the solid state have been made for the following vinylogous series of cyanine dyes: [2-bis(3-ethylthiazolinyl)] cyanine iodides, I; [2-bis(3-ethyl-4-methylthiazolyl)] cyanine iodides, II; and [2-bis(3-ethyl-4,5-diphenylthiozolyl] cyanine iodides, III. Each dye, to be acceptable for study, had to be chromatographically pure, give a correct microchemical elemental analysis, and be free of electron-spin resonance (free radical) signals. These vinylogous series of dyes form a systematic group. That is, in series I there is only a resonant conjugated chain of alternate single and double bonds present between the two nitrogen atoms; in series II there are additional olefinic unsaturated bonds which are in conjugation with the resonant conjugated chain; and in series III there are additional phenyl rings in conjugation with the entire pi bond system present in II. The characteristic red shift of the principal absorption maxima was observed for these dyes in the visible as the number of methine linkages increased. Furthermore, a small relative red shift of the absorption maxima has been observed for this group of dyes and has been interpreted on the basis of the type of unsaturation present in conjugation with the resonant conjugated chain. Assignments of vibrational modes to separate absorption regions have been made for these vinylogous series of dyes. A correlation of the dye structure with the absorption bands has been made. Each vinylog gave rise to a characteristic pattern of resonant conjugated stretching modes in the region 1600 to 1400 cm−1. These modes exhibited a low frequency shift as the resonant conjugated chain-length increased. For a constant number of polymethine linkages these modes are a function of the type of unsaturation present which is in conjugation with the resonant conjugated chain.

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