title: Steady-state and time-resolved spectroscopic characteristics of mesoionic oxazolones solutions.
abstract: Three new mesoionic oxazolo[3,2-b]pyridazin-2-one derivatives, in different solutions have been investigated by UV-Vis absorption, steady-state and time-resolved fluorescence methods. The effect of substituents on the extension of conjugation of the pi-electrons from mesoionic oxazolone has been evidenced by bathochromic shifts of the absorption and fluorescence maxima positions. The fluorescence decay data could be fitted to single-exponential or double-exponential function. The lifetime values are much higher in aprotic polar solvents and in the case of the derivatives that present an extension of the conjugation of pi-electrons. The properties of the compounds present a solvent dependence, being tested in micellar solutions as potential molecular probe "sensitive" to the environment polarity.
authors.affiliation: Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 77208 Bucharest, Romania. mvasilescu@chimfiz.icf.ro
authors.forename: Marilena
authors.initials: M
authors.lastname: Vasilescu
authors.forename: F
authors.initials: F
authors.lastname: Dumitrascu
authors.forename: H
authors.initials: H
authors.lastname: Lemmetyinen
authors.forename: N
authors.initials: N
authors.lastname: Tkachenko
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D008823:Micelles; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents / Q000737:chemistry; D014050:Toluene / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D005456:Fluorescent Dyes; D008823:Micelles; D010080:Oxazoles; D012996:Solutions; D012997:Solvents; D013501:Surface-Active Agents; D014867:Water; D014050:Toluene; D000431:Ethanol; D004121:Dimethyl Sulfoxide; C032159:acetonitrile