title: Excited-State Decay Pathways of Molecular Rotors: Twisted Intermediate or Conical Intersection?
abstract: The fluorescence intensity of molecular rotors containing the dicyanomethylenedihydrofuran (DCDHF) motif increases strongly with solvent viscosity. Single-bond and double-bond rotations have been proposed as pathways of nonradiative decay for this and related molecular rotors. We show here that both are involved in the case of DCDHF rotors: Fluorescence is quenched by rotation around the dicyanomethylene double bond in nonpolar solvents, but in a sufficiently polar environment rotation about a formally single bond leads to a dark internal charge-transfer state.
authors.affiliation: van 't Hoff Institute for Molecular Sciences, University of Amsterdam , P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.|van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam , P.O. Box 94485, 1090 GL Amsterdam, The Netherlands.
authors.forename: Tomislav
authors.initials: T
authors.lastname: Suhina
authors.affiliation: Center for Nanotechnology (CeNTech) and Physical Institute, University of Münster , Heisenbergstrasse 11, 48149 Münster, Germany.
authors.forename: Saeed
authors.initials: S
authors.lastname: Amirjalayer
authors.affiliation: Dipartimento di Chimica e Chimica Industriale, University of Pisa , via G. Moruzzi 13, 56124 Pisa, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Mennucci
authors.affiliation: van 't Hoff Institute for Molecular Sciences, University of Amsterdam , P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.
authors.forename: Sander
authors.initials: S
authors.lastname: Woutersen
authors.affiliation: van 't Hoff Institute for Molecular Sciences, University of Amsterdam , P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: Hilbers
authors.affiliation: van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam , P.O. Box 94485, 1090 GL Amsterdam, The Netherlands.
authors.forename: Daniel
authors.initials: D
authors.lastname: Bonn
authors.affiliation: van 't Hoff Institute for Molecular Sciences, University of Amsterdam , P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.
authors.forename: Albert M
authors.initials: AM
authors.lastname: Brouwer