title: Adducts between dansylated poly(propylene amine) dendrimers and anthracene clips mediated by Zn(II) ions: highly efficient photoinduced energy transfer.
abstract: A family of poly(propylene amine) dendrimers, decorated at their periphery with 4, 16, and 32 dansyl units and a molecular clip, composed of two anthracene sidewalls and a disulfate benzene bridging unit, show intense UV absorption and strong fluorescence in the visible region when in a CH(3)CN/CH(2)Cl(2) (1:1, v/v) solvent mixture. Both these classes of compounds are good ligands for Zn(II) ions, as demonstrated by the changes in the absorption and fluorescence spectra upon addition of metal ions. These coordinating properties have been exploited in the self-assembly of complex structures in which the interaction between a dansylated dendrimer and anthracene-functionalized clips is mediated by Zn(II) ions. The self-assembly process is reversible and the number of metal ions and molecular clips associated with each dendrimer increases with the generation number. In these adducts, an energy transfer process from the anthracene to yield the fluorescent excited state of dansyl takes place with almost unitary efficiency.
authors.affiliation: Dipartimento di Chimica "G. Ciamician", Università di Bologna via Selmi 2, 40126 Bologna (Italy), Fax: (+39) 051-2099456.
authors.forename: Barbara
authors.initials: B
authors.lastname: Branchi
authors.affiliation: Dipartimento di Chimica "G. Ciamician", Università di Bologna via Selmi 2, 40126 Bologna (Italy), Fax: (+39) 051-2099456.
authors.forename: Paola
authors.initials: P
authors.lastname: Ceroni
authors.affiliation: Dipartimento di Chimica "G. Ciamician", Università di Bologna via Selmi 2, 40126 Bologna (Italy), Fax: (+39) 051-2099456.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Balzani
authors.affiliation: Dipartimento di Chimica "G. Ciamician", Università di Bologna via Selmi 2, 40126 Bologna (Italy), Fax: (+39) 051-2099456.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Bergamini
authors.affiliation: Institut für Organische Chemie der Universität Duisburg-Essen, Campus Essen, Universitätsstr. 5, 45117 Essen (Germany), Fax: (+49).
authors.forename: Frank-Gerrit
authors.initials: FG
authors.lastname: Klärner
authors.affiliation: Kekulé-Institut für Organische Chemie und Biochemie der Universität Bonn, Gerhard-Domagk Strasse 1, 53121 Bonn (Germany).
authors.forename: Fritz
authors.initials: F
authors.lastname: Vögtle