TY - JOUR
T1 - Lanthanoid/Alkali Metal β-Triketonate Assemblies: A Robust Platform for Efficient NIR Emitters
AU - Reid, B.L.
AU - Stagni, S.
AU - Malicka, J.M.
AU - Cocchi, M.
AU - Sobolev, Alexandre
AU - Skelton, Brian
AU - Moore, E.G.
AU - Hanan, G.S.
AU - Ogden, M.I.
AU - Massi, M.
PY - 2015/12/7
Y1 - 2015/12/7
N2 - The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxide consistently resulted in the crystallization of neutral tetranuclear assemblies with the general formula [Ln(Ae⋅HOEt)(L)4]2 (Ln=Eu3+, Er3+, Yb3+; Ae=Na+, K+, Rb+). Analysis of the crystal structures of these species revealed a coordination geometry that varied from a slightly distorted square antiprism to a slightly distorted triangular dodecahedron, with the specific geometrical shape being dependent on the degree of lattice solvation and identity of the alkali metal. The near-infrared (NIR)-emitting assemblies of Yb3+ and Er3+ showed remarkably efficient emission, characterized by significantly longer excited-state lifetimes (τobs≈37–47 μs for Yb3+ and τobs≈4–6 μs for Er3+) when compared with the broader family of lanthanoid β-diketonate species, even in the case of perfluorination of the ligands. The Eu3+ assemblies show bright red emission and a luminescence performance (τobs≈0.5 ms, equation image≈35–37 %, ηsens≈68–70 %) more akin to the β-diketonate species. The results highlight that the β-triketonate ligand offers a tunable and facile system for the preparation of efficient NIR emitters without the need for more complicated perfluorination or deuteration synthetic strategies.
AB - The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxide consistently resulted in the crystallization of neutral tetranuclear assemblies with the general formula [Ln(Ae⋅HOEt)(L)4]2 (Ln=Eu3+, Er3+, Yb3+; Ae=Na+, K+, Rb+). Analysis of the crystal structures of these species revealed a coordination geometry that varied from a slightly distorted square antiprism to a slightly distorted triangular dodecahedron, with the specific geometrical shape being dependent on the degree of lattice solvation and identity of the alkali metal. The near-infrared (NIR)-emitting assemblies of Yb3+ and Er3+ showed remarkably efficient emission, characterized by significantly longer excited-state lifetimes (τobs≈37–47 μs for Yb3+ and τobs≈4–6 μs for Er3+) when compared with the broader family of lanthanoid β-diketonate species, even in the case of perfluorination of the ligands. The Eu3+ assemblies show bright red emission and a luminescence performance (τobs≈0.5 ms, equation image≈35–37 %, ηsens≈68–70 %) more akin to the β-diketonate species. The results highlight that the β-triketonate ligand offers a tunable and facile system for the preparation of efficient NIR emitters without the need for more complicated perfluorination or deuteration synthetic strategies.
U2 - 10.1002/chem.201502536
DO - 10.1002/chem.201502536
M3 - Article
C2 - 26511032
SN - 0947-6539
VL - 21
SP - 18354
EP - 18363
JO - CHEMISTRY-A EUROPEAN JOURNAL
JF - CHEMISTRY-A EUROPEAN JOURNAL
IS - 50
ER -