Fluorescence Photoactivation by Intermolecular Proton Transfer

SUBRAMANI SWAMINATHAN; MARCO PETRIELLA; ERHAN DENIZ; JANET CUSIDO; JAMES D. BAKER; MARIANO L. BOSSI; FRANÇISCO M. RAYMO

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2012 vol. 116 p. 9928 - 9933

1089-5639

We designed a strategy to activate fluorescence under the influence of opticalstimulations based on the intermolecular transfer of protons. Specifically, the illumination of a2-nitrobenzyl derivative at an activating wavelength is accompanied by the release of hydrogenbromide. In turn, the photogenerated acid encourages the opening of an oxazine ringembedded within a halochromic compound. This structural transformation extends theconjugation of an adjacent coumarin fluorophore and enables its absorption at an appropriateexcitation wavelength. Indeed, this bimolecular system offers the opportunity to activatefluorescence in liquid solutions, within rigid matrixes and inside micellar assemblies, relyingon the interplay of activating and exciting beams. Furthermore, this strategy permits thepermanent imprinting of fluorescent patterns on polymer films, the monitoring of protondiffusion within such materials in real time on a millisecond time scale, and the acquisition ofimages with spatial resolution at the nanometer level. Thus, our operating principles forfluorescence activation can eventually lead to the development of valuable photoswitchableprobes for imaging applications and versatile mechanisms for the investigation of proton transport.