An Iodine Fluorescence Quenching Clock Reaction.

• Autores: Richard B. Weinberg
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 84, Nº 5, 2007, págs. 797-800
• Idioma: inglés
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• Resumen

  • A fluorescent clock reaction is described that is based on the principles of the Landolt iodine reaction but uses the potent fluorescence quenching properties of triiodide to abruptly extinguish the ultraviolet fluorescence of optical brighteners present in liquid laundry detergents. The reaction uses easily obtained household products. One variation illustrates the sequential steps and mechanisms of the reaction; other variations maximize the dramatic impact of the demonstration; and a variation that uses liquid detergent in the Briggs�Rauscher reaction yields a striking oscillating luminescence. The iodine fluorescence quenching clock reaction can be used in the classroom to explore not only the principles of redox chemistry and reaction kinetics, but also the photophysics of fluorescent pH probes and optical quenching.