A Europium(III) Complex with an Unusual Anion-Cation Interaction: A Luminescent Molecular Thermometer for Ratiometric Temperature Sensing

Mani Outis; César A T Laia; M Conceição Oliveira; Bernardo Monteiro; Cláudia C L Pereira

doi:10.1002/cplu.202000034

A Europium(III) Complex with an Unusual Anion-Cation Interaction: A Luminescent Molecular Thermometer for Ratiometric Temperature Sensing

Chempluschem. 2020 Mar;85(3):580-586. doi: 10.1002/cplu.202000034.

Authors

Mani Outis¹, César A T Laia¹, M Conceição Oliveira², Bernardo Monteiro^{2

3}, Cláudia C L Pereira¹

Affiliations

¹ LAQV-REQUIMTE Departamento de Química, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
² Centro de Ciências e Tecnologias Nucleares (C2TN), DECN, Instituto Superior Técnico, Estrada Nacional 10, 2695-066, Bobadela, Portugal.
³ Centro de Química Estrutural (CQE), DECN, Instituto Superior Técnico, Estrada Nacional 10, 2695-066, Bobadela, Portugal.

PMID: 32212380
DOI: 10.1002/cplu.202000034

Abstract

An unusual thermally sensitive anion-cation interaction, which is characteristic of the anion [Eu(FOD)₄ ]^- , occurs in the complex [CHOL][Eu(FOD)₄ ] (1; CHOL=choline; FOD=1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionate) and affects both quantum yield and thermochromic behavior. This prompted the design of an Eu³⁺ -based ratiometric thermometer that functions at temperatures up to 95 °C through a thermally excited state absorption of the Eu³⁺ ion. The reusable temperature-sensitive luminescent complex showed a range of relative sensitivity between 0.45 % C^-1 at 25 °C, with an increase to 7.0 % C^-1 at 95 °C. Confinement of compound 1 in a transparent film of polysulfone resulted in a higher thermal stability of 1 while its luminescence showed a strong temperature dependence.

Keywords: Lanthanides; luminescence; molecular thermometers; sensors; thermochromic behavior.

Publication types

Research Support, Non-U.S. Gov't