title: Thiazole orange (TO) as a light-switch probe: a combined quantum-mechanical and spectroscopic study.
abstract: A Density Functional Theory (DFT) study of the absorbance and fluorescence emission characteristics of the cyanine thiazole orange (TO) in solution and when intercalated in DNA was carried out in combination with spectrophotometric and spectrofluorometric experiments under different conditions (temperature, concentration, solvent viscosity). T-jump relaxation kinetics of the TO monomer-dimer conversion enabled the thermodynamic parameters of this process to be evaluated. The overall data collected provided information on the features of the "light-switch" by the fluorescent TO and the comparison between experimental and calculated photo-physical properties allowed us to explain and rationalize both shifts and quenching/enhancing effects on fluorescence due to solvation, dimerisation and intercalation in the DNA.
authors.affiliation: Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento, 35, 56126 Pisa, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Biancardi
authors.forename: Tarita
authors.initials: T
authors.lastname: Biver
authors.forename: Alberto
authors.initials: A
authors.lastname: Marini
authors.forename: Benedetta
authors.initials: B
authors.lastname: Mennucci
authors.forename: Fernando
authors.initials: F
authors.lastname: Secco
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D007364:Intercalating Agents / Q000737:chemistry; D008027:Light; D011789:Quantum Theory; D011804:Quinolines / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D052160:Benzothiazoles; D007364:Intercalating Agents; D011804:Quinolines; D012996:Solutions; C051000:thiazole orange; D004247:DNA