Abstract
The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.
Highlights
Luminescence phenomena include photoluminescence (PL) and chemiluminescence, with fluorescence and phosphorescence being particular examples of PL
Two isostructural coordination polymers (CP) based in Sm3+ and
The preparation of TbCP3 involved the use of a co-ligand, the phenanthroline
Summary
Luminescence phenomena include photoluminescence (PL) and chemiluminescence, with fluorescence and phosphorescence being particular examples of PL. In the case of coordination polymers (CP), PL is dependent on the ligand selected for the preparation of the materials Considering these facts, a rational selection of the ligand can promote an efficient absorption and transfer of energy to an excited level of the Ln metal centers, leading to a sensitization of the Ln ions-antenna effect—corresponding to an increase in luminescence efficiency [2,3,4,5]. This occurrence allows the increase of the luminescence intensity of inorganic salts, generally limited by the low absorbance associated with forbidden f –f transitions.
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