Increased luminescent lifetimes of Ln3+ complexes emitting in the near-infrared as a result of deuteration

The luminescence of lanthanide(III) ions emitting in the near-infrared region is ideally suited for telecommunications applications, and a number of applications have been developed. These are in general based on inorganic matrices, but polymer-based matrices would have advantages in device fabrication. In organic matrices, however, molecular vibrations in the matrix quench the excited state of luminescent lanthanide ions. Replacement of strongly quenching groups such as C-H oscillators by more weakly quenching groups enhances the luminescence lifetime and hence also the luminescence quantum yield. This article reports a synthesis route developed in order to deuterate all C-H groups that contribute to the quenching in an organic lanthanide complex. The luminescences of three near-infrared emitting lanthanide ions - Nd3+, Er3+, and Yb3+ - were measured

Visible and near-infrared light emitting calix[4]arene-based ternary lanthanide complexes

In this article ternary lanthanide complexes consisting of a calix[4]arene unit and dibenzoylmethane (dbm) as the antenna are described. In the europium complex [(Eu)2]NO3 two solvent molecules are still coordinated to the ion, making substitution of them by the dbm antenna possible. In the ternary complex of europium, an energy back-transfer process plays an important role. The photophysical properties of complexes of three near-infrared emitting lanthanide(III) ions were determined, i.e. ytterbium, neodymium, and erbium. These exhibit dbm-sensitized emission, with luminescent lifetimes comparable to those in other organic ligand systems

Singlet Energy Transfer as the Main Pathway in the Sensitization of Near-Infrared Nd3+ Luminescence by Dansyl and Lissamine Dyes

general, sensitization of lanthanide(III) ions by organic sensitizers is regarded to take place via the triplet state of the sensitizers. Herein, we show that in dansyl- and lissamine-functionalized Nd3+ complexes energy transfer occurs from the singlet state of the sensitizers to the Nd3+ center. No sensitized emission was observed in the corresponding complexes with Er3+, Yb3+, and Gd3+ ions. Furthermore, the fluorescence of the sensitizers was quenched only in the Nd3+ complex and not in the complexes with the other ions. Only Nd3+ centers can accept energy from the singlet state of the dyes, because the excited states of Nd3+ have a high spectral overlap with the fluorescence of the dansyl and lissamine sensitizers, and because the selection rules allow a fast energy transfer, which apparently is competitive with the fluorescence

Near-infrared and visible luminescence from terphenyl-based lanthanide(III) complexes bearing amido and sulfonamido pendant arms

A series of m-terphenyl-based ligands bearing three coordinating oxyacetate and two amido or two sulfonamido groups, (1a-b)H3 and (2)H3, respectively, have been synthesized and characterized. The structures of the corresponding neutral complexes have been studied using 1H-NMR spectroscopy and luminescence experiments. The photophysical properties of the (1a-b)Eu, (2)Eu, (1a)Tb, and (2)Tb complexes have been studied to determine the structure of the first coordination sphere in methanol. The first coordination sphere consists of eight donor atoms provided by the ligand (three chelating oxyacetate groups and two amide or sulfonamide oxygens), and one methanol molecule. The (1a)Dy and (1a)Sm complexes exhibited sensitized luminescence in the visible spectral region, but the luminescence intensity was very sensitive to quenching by C-H groups. The near-infrared emitting (1a)Ln and (2)Ln complexes exhibited sensitized luminescence at wavelengths (at 880, 1060, and 1330 nm for Nd3+, at 980 nm for Yb3+, and at 1550 nm for Er3+) of interest for applications in optical telecommunication devices. The luminescence lifetimes of these complexes in DMSO and [D6]DMSO are in the range of microseconds. The luminescent state of the NIR emitting lanthanide ions is very efficiently quenched by high frequency oscillators (such as C-H groups) in the solvent and the ligand