Please use this identifier to cite or link to this item:
https://hdl.handle.net/10316/10280
Title: | Self-Aggregation of Lipophilic Porphyrins in Reverse Micelles of Aerosol OT | Authors: | Togashi, Denisio M. Costa, Sílvia M. B. Sobral, Abílio J. F. N. Gonçalves, A. M. d'A. R. |
Issue Date: | 5-Aug-2004 | Publisher: | American Chemical Society | Citation: | The Journal of Physical Chemistry B. 108:31 (2004) 11344-11356 | Abstract: | The aggregation process of meso-tetra(4-aminosulfonylphenyl)porphyrin (PC0), of butyl and dodecyl derivatives (PC4 and PC12, respectively) in the presence of aerosol-OT (AOT) reversed micelles with different values of ω0 = [water]/[AOT] was investigated using steady-state extinction, fluorescence, and resonance light scattering (RLS) techniques. The scattering has been accounted for and the absorption spectra corrected from the extinction spectra. In homogeneous solutions, the porphyrins exist as a monomer showing the Soret band around 420 nm and emission bands at 650 and 716 nm. In reverse micelles, the spectra vary according to the chain length and the amount of solubilized water. Only PC12 is dissolved as a monomer at ω0 = 0, and PC4 shows some degree of aggregation. PC0 is present largely as an aggregate. At ω0 ≠ 0, a complete aggregation is observed for PC4 and PC12, whereas in PC0, some degree of disaggregation was detected. The extinction spectra of PC0 and PC4 in aggregate forms show a broad and red shifted Soret band indicating J aggregates. By contrast, the Soret band intensity of PC12 decreases and a new band around 376 nm appears with a broadening of the monomer Soret band which reflects H aggregates. RLS shows a strong signal for PC12 at red spectral region at high ω0 indicating J aggregate types. The fluorescence spectra showed the new band around 670 nm for PC0 and PC12, whereas in PC4, only blue shifted bands were observed with ω0 increase. The global fluorescence quantum yield of the PC12 aggregates is lower than the respective monomer. The aggregate sizes were followed by RLS measurements which showed an increase of intensity at around 440 nm. The aggregation dynamics is dependent on both the porphyrin concentration and ω0. | URI: | https://hdl.handle.net/10316/10280 | ISSN: | 1520-6106 | DOI: | 10.1021/jp037901p | Rights: | openAccess |
Appears in Collections: | FCTUC Química - Artigos em Revistas Internacionais |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Self-Aggregation of Lipophilic Porphyrins.pdf | 230.04 kB | Adobe PDF | View/Open |
SCOPUSTM
Citations
38
checked on Sep 30, 2024
WEB OF SCIENCETM
Citations
5
38
checked on Sep 2, 2024
Page view(s) 50
451
checked on Oct 1, 2024
Download(s)
283
checked on Oct 1, 2024
Google ScholarTM
Check
Altmetric
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.