title: Photophysical properties of NIR-emitting fluorescence probes: insights from TD-DFT.
abstract: The complex electronic structure and spectroscopic properties of a class of six molecules behaving as near infrared (NIR) fluorescence probes, recently experimentally characterized, are investigated and rationalized using a computational protocol based on Density Functional Theory (DFT) and Time Dependent DFT (TD-DFT). These systems, all belonging to the seminaphthofluorone (SNAFR) series, are characterized by a controlled direction of annulation and regiochemistry of the ionizable moieties significantly tuning the overall absorption and emission features. Experimentally, the overall spectroscopic properties depend both on the pH and on the possible coexistence of different tautomers and regioisomers in solution, thus making the quantitative prediction of their absorption and emission features a challenging task for current ab initio approaches, due to the need for an accurate description of both ground and excited state potential energy landscapes. The results obtained in the present study illustrate the possibility of using a unique computational protocol to describe complex molecular systems in solution not only for the analysis of their intermingled spectroscopic properties but, more interestingly, for the design of new compounds for technological (white emitting dyes) and biological (ratiometric probes) applications.
authors.affiliation: Laboratoire d'Électrochimie, Chimie des Interfaces et Modélisation pour l'Énergie, CNRS UMR-7575, École Nationale Supérieure de Chimie de Paris, Chimie ParisTech, 11 rue P. et M. Curie, F-75231 Paris Cedex 05, France.
authors.forename: Éric
authors.initials: É
authors.lastname: Brémond
authors.forename: Marta E
authors.initials: ME
authors.lastname: Alberto
authors.forename: Nino
authors.initials: N
authors.lastname: Russo
authors.forename: Gino
authors.initials: G
authors.lastname: Ricci
authors.forename: Ilaria
authors.initials: I
authors.lastname: Ciofini
authors.forename: Carlo
authors.initials: C
authors.lastname: Adamo
mesh_terms: D005452:Fluoresceins / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011789:Quantum Theory; D019265:Spectroscopy, Near-Infrared; D013237:Stereoisomerism
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; C401959:seminaphthofluorescein