Gunaydin, KIon, RMScarlat, FScarlat, FNiculescu, VIRMacau, C2024-09-182024-09-1820041454-41641841-7132https://hdl.handle.net/20.500.12483/11784The 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, R(o)values are in the 1-10 Angstrom 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.eninfo:eu-repo/semantics/closedAccessporphyrinsfluorescencequenchinganthaquinonesArticle612892962-s2.0-1842631711Q4WOS:000220389800037Q2