title: Structural and photophysical properties of visible- and near-IR-emitting tris lanthanide(III) complexes formed with the enantiomers of N,N'-bis(1-phenylethyl)-2,6-pyridinedicarboxamide.
abstract: The enantiomers of N,N'-bis(1-phenylethyl)-2,6-pyridinedicarboxamide (L), namely, (R,R)-1, and (S,S)-1, react with Ln(III) ions to give stable [LnL(3)](3+) complexes in an anhydrous acetonitrile solution and in the solid state, as evidenced by electrospray ionization mass spectrometry, NMR, luminescence titrations, and their X-ray crystal structures, respectively. All [LnL(3)](3+) complexes [Ln(III) = Eu, Gd, Tb, and Yb; L = (R,R)-1 and (S,S)-1] are isostructural and crystallize in the cubic space group I23. Although the small quantum yields of the Ln(III)-centered luminescence clearly point to the poor efficiency of the luminescence sensitization by the ligand and the intersystem crossing and ligand-to-metal energy transfers, the ligand triplet-excited-state energy seems relatively well suited to sensitize many Ln(III) ion's emission for instance, in the visible (Eu and Tb), near-IR (Nd and Yb), or both regions (Pr, Sm, Dy, Er, and Tm).
authors.affiliation: Department of Chemistry, San José State University, 1 Washington Square, San José, California 95192-0101, USA.
authors.forename: KimNgan T
authors.initials: KT
authors.lastname: Hua
authors.forename: Jide
authors.initials: J
authors.lastname: Xu
authors.forename: Eliseo E
authors.initials: EE
authors.lastname: Quiroz
authors.forename: Sabrina
authors.initials: S
authors.lastname: Lopez
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Ingram
authors.forename: Victoria Anne
authors.initials: VA
authors.lastname: Johnson
authors.forename: Angela R
authors.initials: AR
authors.lastname: Tisch
authors.forename: Ana
authors.initials: A
authors.lastname: de Bettencourt-Dias
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Straus
authors.forename: Gilles
authors.initials: G
authors.lastname: Muller
mesh_terms: D018360:Crystallography, X-Ray; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011725:Pyridines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism
chemical_list: D028581:Lanthanoid Series Elements; C523726:N,N'-bis(1-phenylethyl)-2,6-pyridinedicarboxamide; D011725:Pyridines