The quantum yield of triplet formation and triplet lifetime in the solid phase by a time-resolved thermal lens method. Application to pyridazine

1988 ◽  
Vol 145 (4) ◽  
pp. 286-288 ◽  
Author(s):  
Masahide Terazima ◽  
Tohru Azumi
2009 ◽  
Vol 62 (5) ◽  
pp. 434 ◽  
Author(s):  
Xian-Fu Zhang ◽  
Yakuan Chang ◽  
Yanling Peng ◽  
Fushi Zhang

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.


2003 ◽  
Vol 07 (09) ◽  
pp. 630-636 ◽  
Author(s):  
Marcelo M. M. Pelisson ◽  
Fernanda M. Tomé ◽  
Milton Beltrame ◽  
Andreza R. Simioni ◽  
Antonio C. Tedesco

The synthesis of a zinc derivative of tribenzonaphthoporphyrazinato ( Zn -tri- PcNc ) obtained from 6-carboxymethyl-2,3-dicyanonaphthalene and phthalonitrile is described. This new phthalocyanine ( Pc ) compound was characterized by 1 H NMR, elemental analyses, IR and UV-vis. The spectroscopic analysis of this compound show an electronic spectrum in DMSO with characteristic bands in the Soret and ϱ region. Steady state and time-resolved spectral analysis revealed a fluorescence quantum yield and a fluorescence lifetime of Φf=0.22 and τf = 2.56 ns respectively, in agreement with other Pc derivatives. This compound also shows a triplet lifetime in air satured solutions of 1.06 μs and a transient with the maximum absortion located at 610 nm, 120 nm shifted to the red compared to the triplet observed by other Pc compounds.


2019 ◽  
Vol 26 (10) ◽  
pp. 758-767
Author(s):  
Vicente Rubio ◽  
Vijaya Iragavarapu ◽  
Maciej J. Stawikowski

Background: Herein we report the multigram-scale synthesis, characterization and application of a rhodamine B-based fluorophore (ROSA) suitable for fluorescent studies in biological applications. This fluorophore is devoid of rhodamine spirolactone formation and furthermore characterized by a high molar extinction coefficient (ϵ=87250 ± 1630 M-1cm-1) and quantum yield (φ) of 0.589 ± 0.070 in water. Reported here is also the application of ROSA towards synthesis of a ROSA-PEG-GRGDS-NH2 fluorescent probe suitable for live cell imaging of αvβ3 integrins for in vitro assays. Objective: The main objective of this study is to efficiently prepare rhodamine B derivative, devoid of spirolactone formation that would be suitable for bioconjugation and subsequent bioimaging. Methods: Rhodamine B was transformed into rhodamine B succinimide ester (RhoB-OSu) using N-hydroxysuccinimide. RhoB-OSu was further coupled to sarcosine to obtain rhodamine Bsarcosine dye (ROSA) in good yield. The ROSA dye was then coupled to a αvβ3 integrin binding sequence using standard solid-phase conditions. Resulting ROSA-PEG-GRGDS-NH2 probe was used to image integrins on cancer cells. Results: The rhodamine B-sarcosine dye (ROSA) was obtained in multigram scale in good total yield of 47%. Unlike rhodamine B, the ROSA dye does not undergo pH-dependent spirolactone/spirolactam formation as compared with rhodamine B-glycine. It is also characterized by excellent quantum yield (φ) of 0.589 ± 0.070 in water and high molar extinction coefficient of 87250 ± 1630 M-1cm-1. ROSA coupling to the RGD-like peptide was proved to be efficient and straightforward. Imaging using standard filters on multimode plate reader and confocal microscope was performed. The αvβ3 integrins present on the surface of live WM-266-4 (melanoma) and MCF- 7 (breast cancer) cells were successfully imaged. Conclusion: We successfully derivatized rhodamine B to create an inexpensive, stable and convenient to use fluorescent probe. The obtained derivative has excellent photochemical properties and it is suitable for bioconjugation and many imaging applications.


Sign in / Sign up

Export Citation Format

Share Document