title: Efficient luminescence from fluorene- and spirobifluorene-based lanthanide complexes upon near-visible irradiation.
abstract: We describe herein the synthesis and photophysical characterization of new lanthanide complexes that consist of a (9,9-dimethylfluoren-2-yl)-2-oxoethyl or a (9,9'-spirobifluoren-2-yl)-2-oxoethyl unit as the antenna, covalently linked to a 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A) unit as the Ln(3+) (Gd(3+), Eu(3+), Sm(3+), Tb(3+), Dy(3+)) coordination site. We were able to translate the spectroscopic properties of the innovative bipartite ligands into the formation of highly luminescent europium complexes that exhibit efficient emission (ϕ(se)>0.1) upon sensitization in the near-visible region, that is, with an excitation wavelength above 350 nm. The luminescence of the Eu(3+) complexes is clearly detectable at concentrations as low as 10 pM. Furthermore, the structural organization of these bipartite ligands makes the complexes highly soluble in aqueous solutions and chemically stable over time.
authors.affiliation: IENI-CNR and INSTM, Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova (Italy).
authors.forename: Gregorio
authors.initials: G
authors.lastname: Bottaro
authors.forename: Fabio
authors.initials: F
authors.lastname: Rizzo
authors.forename: Marco
authors.initials: M
authors.lastname: Cavazzini
authors.forename: Lidia
authors.initials: L
authors.lastname: Armelao
authors.forename: Silvio
authors.initials: S
authors.lastname: Quici
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D005063:Europium / Q000737:chemistry; D005449:Fluorenes / Q000737:chemistry*; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D008163:Luminescent Measurements; D013141:Spiro Compounds / Q000737:chemistry*
chemical_list: C520644:1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid; D056831:Coordination Complexes; D005449:Fluorenes; D006573:Heterocyclic Compounds, 1-Ring; D028581:Lanthanoid Series Elements; D008024:Ligands; D013141:Spiro Compounds; C041509:fluorene; D005063:Europium
keywords: antennas; fluorenes; lanthanides; luminescence; photophysics