resumo
A new molecular thermometric sensor based on the terbium(III) complex [C(2)mim][Tb(fod)4] (C(2)mim - 1-methyl-3-ethylimidazolium, fod(-) - tetrakis-6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate),doped with 0.015% of its europium(III) analogue (1, [C(2)mim][Tb(fod)(4)]0.99985:[C(2)mim][Eu(fod)(4)]0.00015), was prepared and its thermochromic behaviour evaluated from ambient temperature up to 75 degrees C, including in the physiological range (35-45 degrees C). It was found that the intensity ratio of the D-5(4)-> F-7(5) (TbIII) and D-5(0)-> F-7(2) (EuIII) transitions is correlated with temperature having three different linear regimes. Visual colorimetry allowed the evaluation of the temperature in different ranges from green at ambient temperature, to yellow and finally red at higher temperatures. The TbIII complex emission intensity is extremely sensitive to small temperature variations, particularly between 25 and 35 degrees C, were it reaches only 40% of the initial intensity. Confinement of the dopped TbIII tetrakis-complex in the organic polymeric matrix poly(methylmethacrylate) (PMMA) induced higher thermal stability in 1, together with a strong temperature dependence of the most intense emissive transition of the TbIII complexes. The photoluminescence quantum yield of polymer-lanthanide hybrid materials increased significantly compared with that of 1. Under 366 nm irradiation, the hybrid material presents a green colour at 25 degrees C that evolves to yellow at 30 degrees C and to a white tone at 35 degrees C.
palavras-chave
ENERGY-TRANSFER; DINUCLEAR COMPLEXES; CRYSTAL-STRUCTURES; PHASE-TRANSITIONS; IONIC LIQUID; LUMINESCENCE; TERBIUM; EUROPIUM; EMISSION; SENSITIZATION
categoria
Materials Science
autores
Monteiro, B; Leal, JP; Mendes, RF; Paz, FAA; Linden, A; Smetana, V; Mudring, AV; Avo, J; Pereira, CCL
nossos autores
Projectos
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
agradecimentos
This work was supported by the Associated Laboratory for Sustainable Chemistry-Clean Processes and Technologies-LAQV, which is financed by national funds from FCT/MEC (UID/QUI/50006/2019) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER - 007265) . This work was partially developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The NMR spectrometers are part of The National NMR Facility, supported by Fundacao para a Ciencia e a Tecnologia (RECI/BBB-BQB/0230/2012) . This work was also supported by Fundacao para a Ciencia e a Tecnologia (FCT) through the projects UIDB/00100/2020, and by Fundac ao para a Ciencia e a Tecnologia through the contract no IST-ID/077/2018 (Bernardo Monteiro) . Claudia C. L. Pereira thanks Fundacao para a Ciencia e a Tecnologia, MCTES, for the Norma transitoria DL 57/2016 Program Contract. J. A. acknowledges Fundacao para a Ciencia e a Tecnologia (FCT, I.P.) for funding under grant SFRH/BPD/120599/2016 and project PTDC/QUI-QFI/32007/2017. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. RFM gratefully acknowledges FCT for a Junior Research Position (CEECIND/00553/2017) .