Single-Ion Magnet and Photoluminescence Properties of Lanthanide(III) Coordination Polymers Based on Pyrimidine-4,6-Dicarboxylate
Metadatos
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MDPI
Materia
Single-molecule magnets Lanthanide(III) ions Coordination polymer Slow relaxation of the magnetization Photoluminescence
Date
2021Referencia bibliográfica
Pajuelo-Corral, O.; García, J.A.; Castillo, O.; Luque, A.; Rodríguez-Diéguez, A.; Cepeda, J. Single-Ion Magnet and Photoluminescence Properties of Lanthanide(III) Coordination Polymers Based on Pyrimidine-4,6-Dicarboxylate. Magnetochemistry 2021, 7, 8. https://doi.org/10.3390/magnetochemistry7010008
Patrocinador
Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/FEDER, UE) (PGC2018-102052-A-C22, PGC2018-102052-B-C21, PID2019-108028GBC21); Junta de Andalucía (FQM-394); Gobierno Vasco/Eusko Jaurlaritza (IT1005-16, IT1291-19); University of the Basque Country (UPV/EHU) (GIU 17/13, GIU17/50)Résumé
Herein, we report the magnetic and photoluminescence characterization of coordination
polymers (CP) built from the combination of lanthanide(III) ions, pyrimidine-4,6-dicarboxylate
(pmdc) ligand and a co-ligand with formula {[Dy(µ-pmdc)(µ-ox)0.5(H2O)3
]·2H2O}n (1-Dy), {[Dy(µ3
-
pmdc)(µ-ox)0.5(H2O)2
] ~2.33H2O}n (2-Dy), {[Dy2
(µ3
-pmdc)(µ4
-pmdc)(µ-ox)(H2O)3
]·5H2O}n (3-Dy),
{[Ln(µ3
-pmdc)(µ-ox)0.5(H2O)2
]·H2O}n (where Ln(III) = Nd (4-Nd), Sm (4-Sm), Eu (4-Eu) and Dy
(4-Dy)) and {[Dy(µ4
-pmdc)(NO3
)(H2O)]·H2O}n (5-Dy). It must be noted the presence of oxalate
anion acting as ditopic co-ligand in compounds 1-Dy, 2-Dy, 3-Dy and 4-Ln, whereas in 5-Dy the
nitrate anion plays the role of terminal co-ligand. Direct current measurements carried out for
the dysprosium-based CPs reveal almost negligible interactions between Dy3+ ions within the
crystal structure, which is confirmed by computed values of the exchange parameters J. In addition,
alternating current measurements show field-induced single-molecule magnet (SMM) behavior in
compounds 1-Dy, 2-Dy, 4-Dy and 5-Dy, whereas slight-frequency dependence is also observed in
3-Dy. Solid state emission spectra performed at room temperature for those compounds emitting in
visible region confirm the occurrence of significant ligand-to-lanthanide charge transfer in view of
the strong characteristic emissions for all lanthanide ions. Emission decay curves were also recorded
to estimate the emission lifetimes for the reported compounds, in addition to the absolute quantum
yields. Among them, the high quantum yield of 25.0% measured for 4-Eu is to be highlighted as a
representative example of the good emissive properties of the materials.