title: Red-green emitting and superparamagnetic nanomarkers containing Fe3O4 functionalized with calixarene and rare earth complexes.
abstract: The design of bifunctional magnetic luminescent nanomaterials containing Fe3O4 functionalized with rare earth ion complexes of calixarene and β-diketonate ligands is reported. Their preparation is accessible through a facile one-pot method. These novel Fe3O4@calix-Eu(TTA) (TTA = thenoyltrifluoroacetonate) and Fe3O4@calix-Tb(ACAC) (ACAC = acetylacetonate) magnetic luminescent nanomaterials show interesting superparamagnetic and photonic properties. The magnetic properties (M-H and ZFC/FC measurements) at temperatures of 5 and 300 K were explored to investigate the extent of coating and the crystallinity effect on the saturation magnetization values and blocking temperatures. Even though magnetite is a strong luminescence quencher, the coating of the Fe3O4 nanoparticles with synthetically functionalized rare earth complexes has overcome this difficulty. The intramolecular energy transfer from the T1 excited triplet states of TTA and ACAC ligands to the emitting levels of Eu(3+) and Tb(3+) in the nanomaterials and emission efficiencies are presented and discussed, as well as the structural conclusions from the values of the 4f-4f intensity parameters in the case of the Eu(3+) ion. These novel nanomaterials may act as the emitting layer for the red and green light for magnetic light-converting molecular devices (MLCMDs).
authors.affiliation: Institute of Chemistry, Department of Fundamental Chemistry, University of São Paulo , Av. Prof. Lineu Prestes, 748, 05508-000 São Paulo-SP, Brazil.
authors.forename: Latif U
authors.initials: LU
authors.lastname: Khan
authors.forename: Hermi F
authors.initials: HF
authors.lastname: Brito
authors.forename: Jorma
authors.initials: J
authors.lastname: Hölsä
authors.forename: Kleber R
authors.initials: KR
authors.lastname: Pirota
authors.forename: Diego
authors.initials: D
authors.lastname: Muraca
authors.forename: Maria C F C
authors.initials: MC
authors.lastname: Felinto
authors.forename: Ercules E S
authors.initials: EE
authors.lastname: Teotonio
authors.forename: Oscar L
authors.initials: OL
authors.lastname: Malta