title: Long-lived near-infrared luminescent lanthanide complexes of imidodiphosphinate "shell" ligands.
abstract: Near-infrared emitting complexes of Nd(III), Er(III), and Yb(III) based on hexacoordinate lanthanide ions with an aryl functionalized imidodiphosphinate ligand, tpip, have been synthesized and fully characterized. Three tpip ligands form a shell around the lanthanide with the ligand coordinating via the two oxygens leading to neutral complexes, Ln(tpip)3. In the X-ray crystal structures of Er(III) and Nd(III) complexes there is evidence of CH-pi interactions between the phenyl groups. Photophysical investigations of solution samples of the complexes demonstrate that all complexes exhibit relatively long luminescence lifetimes in nondeuteurated solvents. Luminescence studies of powder samples have also been recorded for examination of the properties of NIR complexes in the solid state for potential material applications. The results underline the effective shielding of the lanthanide by the twelve phenyl groups of the tpip ligands and the reduction of high-energy vibrations in close proximity to the lanthanide, both features important in the design of NIR emitting lanthanide complexes.
authors.affiliation: School of Chemistry, University of Birmingham, Edgbaston B15 2TT, UK.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Bassett
authors.forename: Rik
authors.initials: R
authors.lastname: Van Deun
authors.forename: Peter
authors.initials: P
authors.lastname: Nockemann
authors.forename: Peter B
authors.initials: PB
authors.lastname: Glover
authors.forename: Benson M
authors.initials: BM
authors.lastname: Kariuki
authors.forename: Kristof
authors.initials: K
authors.lastname: Van Hecke
authors.forename: Luc
authors.initials: L
authors.lastname: Van Meervelt
authors.forename: Zoe
authors.initials: Z
authors.lastname: Pikramenou
mesh_terms: D004164:Diphosphonates / Q000737:chemistry*; D007259:Infrared Rays; D028581:Lanthanoid Series Elements / Q000737:chemistry* / Q000528:radiation effects*; D008024:Ligands; D049449:Luminescence; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D013997:Time Factors
chemical_list: D004164:Diphosphonates; D028581:Lanthanoid Series Elements; D008024:Ligands; C016514:imidodiphosphonic acid