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STUDY OF THE FLUORESCENCE-QUENCHING OF Mg-TNP BY ANIONIC ANTHRAQUINONES

K. Gunaydin1, R.-M. Ion2,* , F. Scarlat3, Fl. Scarlat4, V. I. R. Niculescu4, C. Macau4

Affiliation

  1. Mustafa Kemal University, Faculty of Sciences and Letters, Antakya-Hatay,Turkey
  2. Institute for Chemical Research - ICECHIM, Chemical Analysis Department, Bucharest, Romania
  3. Valahia University of Targoviste, Faculty of Sciences, Targoviste, Romania
  4. National Institute for Laser, Plasma and Radiation Physics, Bucharest, Romania

Abstract

The fluorescence quenching of magnesium 5,10,15,20-tetra-p-naphtyl-porphyrin (Mg-TNP) has been studied in benzene using 9,10-anthraquinone-2-sulfonic acid sodium salt (An 1), 9,10 -anthraquinone-2,6-disulfonic acid sodium salt monohydrate (An 2), 9,10-anthraquinone 1,5-disulfonic disodium salt monohydrate (An 3) as quenchers. The fluorescence quenching rate constants are deduced from the Stern-Volmer curves and it is postulated that the quenching occurs via the formation of a charge transfer complex formation. For all these cases, Ro values are in the 1-10 Å range, which correspond to one singlet quenching processes by diffusion controlled energy transfer. Electron-exchange and/or electron transfer processes are expected to proceed also at these distances. The quenching mechanism is concerted one between static quenching with energy transfer (due to long-range dipole-dipole interaction between excited anthraquinone molecules (donor) and the ground state acceptor molecule Mg-TNP) and electron transfer which should occur from singlet excited state of Mg-TNP to donor anthraquinone molecule, leading to formation of stable radical anion and cations..

Keywords

Porphyrins, Fluorescence, Quenching, Anthaquinones.

Submitted at: June 10, 2003
Accepted at: March 15, 2004

Citation

K. Gunaydin, R.-M. Ion, F. Scarlat, Fl. Scarlat, V. I. R. Niculescu, C. Macau, STUDY OF THE FLUORESCENCE-QUENCHING OF Mg-TNP BY ANIONIC ANTHRAQUINONES, Journal of Optoelectronics and Advanced Materials Vol. 6, Iss. 1, pp. 289-296 (2004)