Metal nanoparticles concentration effects on the photophysical properties of molecular and supramolecular probes

MOLINA TORRES, MARÍA ANDREA; NÚÑEZ, RODRIGO NICOLÁS; VEGLIA, ALICIA VIVIANA; PACIONI, NATALIA LORENA

Villa Carlos Paz, Córdoba

Congreso; XIII Encuetro Latinoamericano de Fotoquímica y Fotobiología; 2017

Effect of metal nanoparticles concentration on the photophysical properties of molecular and supramolecular probes. María Andrea Molina Torres&, Rodrigo N. Núñez&, Alicia V. Veglia and Natalia L. Pacioni INFIQC-CONICET and Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Química Orgánica. Haya de la Torre y Medina Allende s/n, Ciudad Universitaria, X5000HUA, Córdoba, Argentina.e-mail: nataliap@fcq.unc.edu.ar. &Equal contribution. Nowadays, it is widely accepted metal nanoparticles (NP) affect the photophysical and photochemical performance of molecules located close or in contact with the metal surface in different ways. Either quenching or enhancement of their properties can be produced, and factors affecting these phenomena are NP size, composition, shape as well as distance of the molecule from the surface [1-2]. Although, the mentioned properties variations are continually explored to improve molecule sensing, reports on the effect of nanoparticle concentration on the photophysical properties such as fluorescence are still scarce. On the other hand, due to the environmental implications NP can have, in the last years it has been an increased interest on developing analytical methods oriented to the detection of NP. In this frame, our aim is to explore the NP concentration dependance of the photophysical properties of molecular probes and supramolecular complexes as an strategy to detect metal nanoparticles in mixtures. In this work we selected Rhodamine B and 6G (RhB and Rh6G, respectively) as molecular probes and carbazol@cyclodextrins (CZL@CDs) as the supramolecular systems; and colloidal AgNP (citrate, gallic acid or stabilized by a gemini surfactant) and AuNP (citrate stabilized) as the tested NP. We evaluated the effect on the fluorescence of RhB, Rh6G and CZL@CDs of the presence of different NP at different concentrations with or without pH control. A comparison between all the systems will be discussed. AcknowledgmentsWe want to thanks Dr. Mariana Fernandez and Lic. Erica Pachón Gómez for providing the gemini surfactant. We also would like to thank ANPCyT, SECYT-UNC and CONICET for funding this project. References[1] J. R. Lakowicz, Principles of Fluorescence Spectroscopy, 3rd ed., Springer, 2006; [2] S. K. Ghosh and T. Pal, Phys. Chem. Chem. Phys., 2009, 11, 3811.