Luminescent and proton conducting lanthanide coordination networks based on a zwitterionic tripodal triphosphonate
Angeli, Giasemi K.
Papathanasiou, Konstantinos E.
Salcedo, Inés R.
Losilla, Enrique R.
Hix, Gary B.
Demadis, Konstantinos D.
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AbstractThe synthesis, structural characterization, luminescence properties, and proton conduction performance of a new family of isostructural cationic 2D layered compounds are reported. These have the general formula [Ln(H4NMP)(H2O)2]Cl·2H2O [Ln = La3+, Pr3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, H6NMP = nitrilotris(methylphosphonic acid)], and contain Cl– as the counterion. In the case of Ce3+, a 1D derivative, [Ce2(H3NMP)2(H2O)4]·4.5H2O, isostructural with the known lanthanum compound has been isolated by simply crystallization at room temperature. The octa-coordinated environment of Ln3+ in 2D compounds is composed by six oxygen atoms from three different ligands and two oxygens from each bound water. Two of the three phosphonate groups act as both chelating and bridging linkers, while the third phosphonate group acts solely as a bridging moiety. The materials are stable at low relative humidity at less at 170 °C. However, at high relative humidity transform to other chloride-free phases, including the 1D structure. The proton conductivity of the 1D materials varies in a wide range, the highest values corresponding to the La derivative (σ ≈ 2 × 10–3 S·cm–1 at RH 95% and 80 °C). A lower proton conductivity, 3 × 10–4 S·cm–1, was measured for [Gd(H4NMP)(H2O)2]Cl·2H2O at 80 °C, which remains stable under the work conditions used. Absorption and luminescence spectra were recorded for selected [Ln(H4NMP)(H2O)2]Cl·2H2O compounds. In all of them, the observed transitions are attributed solely to f–f transitions of the lanthanide ions present, as the H4NMP2– organic group has no measurable absorption or luminescence properties.
CitationBazaga-García M., Angeli GK., Papathanasiou KE., Salcedo IR., Olivera-Pastor P., Losilla ER., Choquesillo-Lazarte D., Hix GB., Cabeza A., Demadis KD. (2016) 'Luminescent and proton conducting lanthanide coordination networks based on a zwitterionic tripodal triphosphonate', Inorganic Chemistry, 55 (15) pp. 7414-7424 doi: 10.1021/acs.inorgchem.6b00570
PublisherAmerican Chemical Society
DescriptionThis is an accepted manuscript of an article published by American Chemical Society in Inorganic Chemistry on 14/07/2016, available online: https://doi.org/10.1021/acs.inorgchem.6b00570 The accepted version of the publication may differ from the final published version.