title: Polar fluorenes and spirobifluorenes: fluorescence and fluorescence anisotropy spectra.
abstract: An extensive spectroscopic study is presented of two asymmetrically substituted fluorene dyes and of the related spiro dimers in both liquid and glassy solvents. Essential-state models are developed to accurately reproduce linear absorption and fluorescence spectra and their complex dependence on solvent polarity. The same models are exploited to quantitatively calculate fluorescence excitation and anisotropy spectra in rigid matrixes. Impressive red-edge effects observed for spiro dimers in glassy polar solvents are accurately reproduced and understood. Interchromophore interactions in the spiro dimers are very small, leading to marginal effects in absorption and fluorescence spectra, but they effectively promote energy transfer between the two chromophores, as best evidenced comparing anisotropy spectra of the substituted fluorenes and of corresponding spiro dimers dissolved in glassy solvent matrixes.
authors.affiliation: Dipartimento di Chimica GIAF and INSTM-UdR Parma, Università degli studi di Parma, Parco Area delle Scienze 17/a, 43124 Parma, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Grisanti
authors.forename: Francesca
authors.initials: F
authors.lastname: Terenziani
authors.forename: Cristina
authors.initials: C
authors.lastname: Sissa
authors.forename: Marco
authors.initials: M
authors.lastname: Cavazzini
authors.forename: Fabio
authors.initials: F
authors.lastname: Rizzo
authors.forename: Simonetta
authors.initials: S
authors.lastname: Orlandi
authors.forename: Anna
authors.initials: A
authors.lastname: Painelli