title: Luminescent dinuclear lanthanide complexes of 5-Me-HXTA.
abstract: The synthesis and characterization of a series of anionic homobimetallic lanthanide complexes of the septadentate chelate 5-Me-HXTA (N,N-(2 hydroxy-5-methyl-1,3-xylylene)bis(N-(carboxymethyl)glycine) is described (Ln = Nd, Sm, Eu, Tb, Dy, Ho, Er, Yb). Single X-ray crystallography confirms that the complexes exist as discrete dimeric pairs in the solid state. Proton NMR, diffusion-ordered spectroscopy, and luminescence solution studies suggest that the binuclear stoichiometry is retained in aqueous solution over a range of analytically useful concentrations. The phenolic chromophores effectively sensitize the visible and near-infrared lanthanide-centered emission in the terbium, neodymium, and ytterbium derivatives, giving rise to particularly long-lived green and near-infrared emission. The terbium complex displays a high quantum yield of around 50% in aqueous solution with a low detection limit of 1 x 10(-12) M, rendering this compound a potential candidate for time-resolved applications.
authors.affiliation: Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Louise S
authors.initials: LS
authors.lastname: Natrajan
authors.forename: Phillipa L
authors.initials: PL
authors.lastname: Timmins
authors.forename: Matthew
authors.initials: M
authors.lastname: Lunn
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Heath
mesh_terms: D018360:Crystallography, X-Ray; D007700:Kinetics; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008163:Luminescent Measurements; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010777:Photochemistry; D013997:Time Factors
chemical_list: D028581:Lanthanoid Series Elements; D009942:Organometallic Compounds