Structure and dynamics of micelle-based fluorescent sensor for transition metals

A structural model of the fluorescent supramolecular sensor Triton X-100:pyrene:dodecyl-dioxo-2,3,2 is proposed, based on a micellar approach. Under the experimental conditions, phase behavior of the micellar solution restricts ligand:surfactant ratio to 1:10. Thermodynamic and kinetic data indicate that the quenching mechanism involved in the ON-OFF response is intramicellar, and selective compartmentalization of fluorophore and quencher inside micelles can affect effective collisions. An oblate ellipsoid is proposed as the most suitable structure for this micellar-based sensor. Main structural properties of surfactant aggregates and the complex itself are not affected by this assembling, suggesting that the micelle acts as a dynamic substrate. (C) 2004 Elsevier B.V. All rights reserved.