title: Fluorescence photoactivation by intermolecular proton transfer.
abstract: We designed a strategy to activate fluorescence under the influence of optical stimulations based on the intermolecular transfer of protons. Specifically, the illumination of a 2-nitrobenzyl derivative at an activating wavelength is accompanied by the release of hydrogen bromide. In turn, the photogenerated acid encourages the opening of an oxazine ring embedded within a halochromic compound. This structural transformation extends the conjugation of an adjacent coumarin fluorophore and enables its absorption at an appropriate excitation wavelength. Indeed, this bimolecular system offers the opportunity to activate fluorescence in liquid solutions, within rigid matrixes and inside micellar assemblies, relying on the interplay of activating and exciting beams. Furthermore, this strategy permits the permanent imprinting of fluorescent patterns on polymer films, the monitoring of proton diffusion within such materials in real time on a millisecond time scale, and the acquisition of images with spatial resolution at the nanometer level. Thus, our operating principles for fluorescence activation can eventually lead to the development of valuable photoswitchable probes for imaging applications and versatile mechanisms for the investigation of proton transport.
authors.affiliation: Laboratory for Molecular Photonics, Department Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146-0431, USA.
authors.forename: Subramani
authors.initials: S
authors.lastname: Swaminathan
authors.forename: Marco
authors.initials: M
authors.lastname: Petriella
authors.forename: Erhan
authors.initials: E
authors.lastname: Deniz
authors.forename: Janet
authors.initials: J
authors.lastname: Cusido
authors.forename: James D
authors.initials: JD
authors.lastname: Baker
authors.forename: Mariano L
authors.initials: ML
authors.lastname: Bossi
authors.forename: Françisco M
authors.initials: FM
authors.lastname: Raymo
mesh_terms: D005453:Fluorescence; D018054:Hydrobromic Acid / Q000737:chemistry*; D055668:Photochemical Processes; D011522:Protons
chemical_list: D011522:Protons; D018054:Hydrobromic Acid