Long‐Range LMCT Coupling in Eu<sup>III</sup> Coordination Polymers for an Effective Molecular Luminescent Thermometer**
Yuichi Kitagawa, Marina Kumagai, Pedro Paulo Ferreira da Rosa, Koji Fushimi, Yasuchika Hasegawa
Abstract
Abstract A design for an effective molecular luminescent thermometer based on long‐range electronic coupling in lanthanide coordination polymers is proposed. The coordination polymers are composed of lanthanide ions Eu III and Gd III , three anionic ligands (hexafluoroacetylacetonate), and a chrysene‐based phosphine oxide bridges (6,12‐bis(diphenylphosphoryl)chrysene). The zig‐zag orientation of the single polymer chains induces the formation of packed coordination structures containing multiple sites for CH‐F intermolecular interactions, resulting in thermal stability above 350 °C. The electronic coupling is controlled by changing the concentration of the Gd III ion in the Eu III ‐Gd III polymer. The emission quantum yield and the maximum relative temperature sensitivity ( S m ) of emission lifetimes for the Eu III ‐Gd III polymer (Eu:Gd=1:1, Φ tot =52 %, S m =3.73 % K −1 ) were higher than those for the pure Eu III coordination polymer ( Φ tot =36 %, S m =2.70 % K −1 ), respectively. Enhanced temperature sensing properties are caused by control of long‐range electronic coupling based on phosphine oxide with chrysene framework.