Long‐Range LMCT Coupling in Eu^III Coordination Polymers for an Effective Molecular Luminescent Thermometer**

Abstract

Ad esign for an effective molecular luminescent thermometerb ased on long-range electronic coupling in lanthanide coordination polymers is proposed. The coordination polymers are composed of lanthanide ions Eu III and Gd III ,t hree anionic ligands(hexafluoroacetylacetonate), and ac hrysene-based phosphine oxide bridges (6,12-bis(diphenylphosphoryl)chrysene). The zig-zago rientation of the single polymerc hains induces the formation of packed coordination structuresc ontaining multiple sites forC H-F intermolecular interactions, resulting in thermal stability above 350 8C. The electronic coupling is controlledb yc hanging the concentration of the Gd III ion in the Eu III-Gd III polymer.T he emission quantum yield and the maximum relative temperature sensitivity (S m)o fe mission lifetimesf or the Eu III-Gd III polymer (Eu:Gd = 1:1, F tot = 52 %, S m = 3.73 %K À1)w ere higher than those for the pure Eu III coordination polymer (F tot = 36 %, S m = 2.70 %K À1), respectively.E nhanced temperature sensing properties are causedb yc ontrol of long-range electronic coupling based on phosphine oxide with chrysene framework.

Rationalizing the Thermal Response of Dual‐Center Molecular Thermometers: The Example of an Eu/Tb Coordination Complex

“…The theoretical method presented is also capable to include ligand-to-metal charge transfer states (LMCT) and their interactions with other states (i.e., S 1 , T 1 , and Ln 3+ levels), treating the energy transfer rates involving the LMCT and including it in a rate equation model. [67,72,83] Thus, discernible thermal behavior in which the LMCT plays an important role in Ln 3+ -based molecular thermometers [84,85] could be also modeled.…”

Bright red emission with high color purity from Eu(iii) complexes with π-conjugated polycyclic aromatic ligands and their sensing applications

“…6d ). 56 The single polymer chains show the characteristic zig-zag orientation, inducing multiple CH–F interactions, and exhibit higher thermal stability ( T d = 358 °C) than the mononuclear Eu( iii ) complex. The relative thermal sensitivity ( S m ) of the Eu( iii ) coordination polymer with chrysene linkers was higher ( S m = 2.70% K −1 at 475 K) than those of mononuclear Eu( iii ) complexes ( S m = 0.89% K −1 at 475 K).…”

Coordination Geometrical Effect on Ligand-to-Metal Charge Transfer-Dependent Energy Transfer Processes of Luminescent Eu(III) Complexes

“…The LMCT bands of Eu(III) complexes with organic anion ligands such as acetylacetonate (acac), 25 trimethylheptanoate (tmh), 26−29 polycyclic aromatic hydrocarbons, 30,31 and dialkyldithiocarbamates 32,33 have been reported. Faustino reported a theoretical approach for understanding the influence of LMCT bands in lanthanide compounds and found that the energy levels of triplet and LMCT bands are important for efficient europium ion sensitization.…”