title: Highly luminescent lanthanide complexes of 1-hydroxy-2-pyridinones.
abstract: The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III), and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission (Phi tot (Eu) approximately 21.5%) with high stability (pEu approximately 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure and were found to agree with corresponding time-dependent density functional theory (TD-DFT) calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure.
authors.affiliation: Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA.
authors.forename: Evan G
authors.initials: EG
authors.lastname: Moore
authors.forename: Jide
authors.initials: J
authors.lastname: Xu
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Jocher
authors.forename: Ingrid
authors.initials: I
authors.lastname: Castro-Rodriguez
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Raymond
mesh_terms: D018360:Crystallography, X-Ray; D004247:DNA / Q000032:analysis; D007202:Indicators and Reagents; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D049449:Luminescence; D008968:Molecular Conformation; D011506:Proteins / Q000032:analysis; D011725:Pyridines / Q000737:chemistry; D011728:Pyridones / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics
chemical_list: D007202:Indicators and Reagents; D028581:Lanthanoid Series Elements; D011506:Proteins; D011725:Pyridines; D011728:Pyridones; D012996:Solutions; C014047:hydroxypyridines; D004247:DNA