title: Photophysical properties of quinolizinium salts and their interactions with DNA in aqueous solution.
abstract: The photophysical properties of three quinolizinium salts (naphto[2,1-b]quinolizinium bromide (Q2), naphto[1,2-b]quinolizinium bromide (Q3), and indolo[2,3-b]quinolizinium tetrafluoroborate (HI)) in fluid media and their interactions with DNA were investigated by steady-state and by nanosecond and femtosecond time-resolved techniques. The main decay pathways of the excited singlet state S(1), fluorescence, intersystem crossing, and internal conversion, were characterized in terms of quantum yields and rate constants. The lowest triplet state of the quinolizinium salts is able to sensitize singlet oxygen in rather high efficiency (phi(Delta) = 0.4 to 0.5 in MeCN). The complexes between quinolizinium salts and DNA formed in the ground state were characterized in terms of lifetimes and decay channels to give more details of the mechanism of photoinduced DNA strand break.
authors.affiliation: Dipartimento di Chimica and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati, via Elce di Sotto 8, Perugia 06123, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Barbafina
authors.forename: Matteo
authors.initials: M
authors.lastname: Amelia
authors.forename: Loredana
authors.initials: L
authors.lastname: Latterini
authors.forename: Gian Gaetano
authors.initials: GG
authors.lastname: Aloisi
authors.forename: Fausto
authors.initials: F
authors.lastname: Elisei
mesh_terms: D000042:Absorption; D004247:DNA / Q000378:metabolism*; D011807:Quinolizines / Q000737:chemistry* / Q000378:metabolism*; D012492:Salts / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D011807:Quinolizines; D012492:Salts; D012996:Solutions; D014867:Water; D004247:DNA