resumo
The synthesis and characterization of six new lanthanide networks [Ln(L)(ox)(H2O)] with Ln = Eu3+, Gd3+, Tb3+ , Dy3+ , Ho3+ and Yb3+ is reported. They were synthesized by solvo-ionothermal reaction of lanthanide nitrate Ln(NO3)(3)center dot xH(2)O with the 1,3-bis(carboxymethyl)imidazolium [HE] ligand and oxalic acid (H(2)ox) in a water/ethanol solution. The crystal structure of these compounds has been solved on single crystals and the magnetic and luminescent properties have been investigated relying on intrinsic properties of the lanthanide ions. The synthetic strategy has been extended to mixed lanthanide networks leading to four isostructural networks of formula [Tb1-xEux(L)(ox)(H2O)] with x = 0.01, 0.03, 0.05 and 0.10. These materials were assessed as luminescent ratiometric thermometers based on the emission intensities of ligand, Tb3+ and Eu3+ . The best sensitivities were obtained using the ratio between the emission intensities of Eu3+ (D-5(0) -> F-7(2) transition) and of the ligand as the thermometric parameter. [Tb0.97Eu0.03 (L)(ox)(H2O)] was found to be one of the best thermometers among lanthanide-bearing coordination polymers and metal-organic frameworks, operative in the physiological range with a maximum sensitivity of 1.38%.K-1 at 340 K.
palavras-chave
METAL-ORGANIC FRAMEWORKS; IONIC LIQUIDS; TEMPERATURE-RANGE; SLOW RELAXATION; LIGHT-EMISSION; POLYMERS; MOF; COMPLEXES; FLUORESCENCE; DYSPROSIUM
categoria
Science & Technology - Other Topics; Materials Science; Physics
autores
Farger, P; Leuvrey, C; Gallart, M; Gilliot, P; Rogez, G; Rocha, J; Ananias, D; Rabu, P; Delahaye, E
nossos autores
Duarte Ananias
Investigador Auxiliar
João Rocha
Prof. CatedráticoProjectos
agradecimentos
The authors thank the Centre National de la Recherche Scientifique (CNRS), the Universite de Strasbourg (Idex), the Labex NIE (ANR-11-LABX-0058_NIE within the Investissement d'Avenir program ANR-10-IDEX-0002-02), the Agence Nationale de la Recherche (ANR contract no. ANR-15-CE08-0020-01) and the icFRC (http://www.icfrc.fr) for funding. Part of the present work comes from the thesis of Pierre Farger [32] and is part of the research activity supported by the European COST action MP1202: HINT (Rational design of hybrid organic-inorganic interfaces: the next step towards advanced functional materials. http://www.cost-hint.cnrs.fr).This work was also developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Fundacao para a Ciencia e a Tecnologia, FCT, Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC (Ministerio da Educacao e Ciencia) and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. D.A. (SFRH/BPD/95032/2013) thanks FCT for a post-doctoral grant. The authors are grateful to Didier Burger for technical assistance.S