Luminescent and colorimetric sensors for anions

ORGN 277

Thorfinnur Gunnlaugsson, gunnlaut@tcd.ie, Paul E Kruger, Gillian M Hussey, Juliann Tierney, and Haslin Dato Paduka Ali. School of Chemistry, University of Dublin, Trinity College Dublin, Dublin 2, Ireland, College Green, Dublin, 2, Ireland
Luminescent and colorimetric anion recognition and sensing is a rapidly developing field within supramolecular chemistry. We recently demonstrated the first examples of photoinduced electron transfer PET anion sensing using charge-neutral thiourea and urea hydrogen bonding motifs, where the emission was quenched upon anion recognition by ions such as acetate and fluoride in organic solvents. Despite these successes, there is a need to develop receptors capable of anion binding within competitive media. Here we present several novel naphthalimide-based sensors which belong to a family of new charge-neutral colorimetric internal charge transfer (ICT) chemosensors. We demonstrated that the recognition of biologically important anions is achieved in aqueous solution via hydrogen bonding at charge neutral sites which can be monitored by changes in their ground and excited states. Furthermore, the anion binding is accompanied by a visually striking color change, giving naked eye anion sensing even after immobilization of these sensors onto materials.