Ligand Design for Luminescent Lanthanide-Containing Metallopolymers

Abstract

The isolation of emissive materials with lanthanide ions is a topic of interest for imaging, display, and sensing applications, and it requires tuning of the electronics of the systems, such that, during the process of sensitization of the metal-centered luminescence, energy transfer from the sensitizer to the lanthanide ion is efficient and the resulting materials have the characteristics required for a given application. We discuss here our group's work in controlling the singlet- and triplet-state energies of sensitizing ligands through the choice of functional groups on the pyridine rings chelating to the lanthanide ions and show how we achieved progressively higher emission efficiencies. We describe targeted functionalization that led to highly emissive systems in solution and in the solid state and to new metallopolymers with norbornene or dicyclopentadiene-based backbones and pyridinebis(oxazoline) pendants, which display red Eu-based, green Tb-based, and, for the first time, blue Tm-based emission.

Robust and Reversible Vapoluminescent Organometallic Copper Polymers

“…The quantum yield of Cu(I)‐coordinated polymers was 11%, much lower than the [CuBr(PPh 3 ) 2 (4‐Mepy)] small molecule itself (96%). This should be largely attributed by the amorphous nature of polymers compared with the ordered small molecules, similar to many previous reports when introducing emitters into polymeric systems . Different loadings of CuBr did not shift the photoluminescence (PL) peak position (500 nm), but the peak intensity was continuously increasing with the concentration of [CuBr(PPh 3 ) 2 (4‐Mepy)] in the polymeric matrix (Figure B).…”

“…In sharp contrast, emissive organometallic polymers are far less explored as flexible luminescent materials . This is possibly attributed by the difficulties in finding suitable and stable (thermally and oxidatively) organometallic emitters for polymer backbones, leading the studies in the limited categories of organometallic molecules, such as pyridine‐based heavy metal complexes, lanthanide molecules, and iridium compounds . Compared with traditional organic conjugated polymers, organometallic light‐emitting polymers exhibited many distinguished properties, such as diverse choices on the metals and ligands, better processability for applications, and unique functionality from organometallic molecules …”

Pybox-Iron(II) Spin-Crossover Complexes with Substituent Effects from the 4-Position of the Pyridine Ring (Pybox = 2,6-Bis(oxazolin-2-yl)pyridine)

“…The ligands X-pybox (X = H [23], Cl [28], Ph [29], and CH 3 O [30]) were prepared according to the known procedure. A new derivative CH 3 S-pybox was prepared according to the known procedure for the CH 3 O-pybox [30] with modification.…”

“…New compounds [Fe(X-pybox)2](ClO4)2 (X = Cl, Ph, CH3O, CH3S) were prepared according to the conventional method [23,[28][29][30]. All the ligands were known, except for X = CH3S.…”

Sensitization of LnIII (Ln = Eu, Tb, Tm) Ion Luminescence by Functionalized Polycarbonate‐Based Materials and White Light Generation

“…[38] Recently, our group reported the first example of a metallopolymer with norbornene-based backbone and pyridine-2,6-bis(oxazoline) pendants that sensitized blue Tm III -centered emission in the solid-state. [39] Thus, the BEP polymer is another rare example of a polymer capable of sensitizing blue Tm III -centered emission. However, since the energy transfer is inefficient, the emission lifetime and quantum yield could not be determined reliably.…”