Stark Sublevel-Based Thermometry with Tb(III) and Dy(III) Complexes Cosensitized via the 2-Amidinopyridine Ligand

Abstract

Amidine-based ligand frameworks were employed to isolate a series of mononuclear lanthanide complexes. The employed N-2-pyridyl­imidoyl-2-pyridyl­amidine (Py2ImAm) undergoes metal-assisted hydrolysis yielding the ligand 2-amidino­pyridine (PyAm), which coordinates to the lanthanide ions affording [Ln­(acac)3(PyAm)], where Ln = Eu­(III) (1), Gd­(III) (2), Tb­(III) (3), Dy­(III) (4) along with the Y­(III) analogue (5). The Eu­(III), Tb­(III), and Dy­(III) congeners exhibit characteristic emissions of red, green, and yellow light, respectively, with emission quantum yields of 3, 65, and 8%, respectively. Due to changes in the thermal population of the Stark sublevels, the Tb­(III) and Dy­(III) complexes can be used as efficient optical thermometers with maximum relative sensitivities of 1.57 and 2.03% K–1 for 3 and 4, respectively. These results demonstrate the viability of PyAm as an antenna for the sensitization of lanthanide ions.

A Multifunctional Dysprosium‐Carboxylato 2D Metall–Organic Framework

“…However,t he diluted species 1d displayed the emission spectra for Dy III when excited at 280 nm. We confirm thus the antenna effect from the benzoato ligands.T he quantum yield of the emission was relatively high for aD ycomplex (QY = 4%), [41,42] and the luminescent lifetime was 50 ms(Figure 5). It is concluded that high concentration of Dy III centers in 1 quenches the luminescence.Once the Dy III ions are isolated in 1d,luminescence can be observed.…”

Thermal Dependence of the Luminescent Properties of Mononuclear TbIII Macrocyclic Complexes

“…[11] Other authors also report a variety of methodologies to evaluate optical thermometry. [34][35][36][37] With the purpose of demonstrating the thermometric potential of the studied complexes, the effect of temperature on the total area of the emission bands was analysed. Basic thermometer performance parameters were calculated for TbL 1 NO 3 and TbL 3 NO 3 , which showed the greatest intensities.…”

A Multifunctional Dysprosium‐Carboxylato 2D Metall–Organic Framework

“…We confirm thus the antenna effect from the benzoato ligands. The quantum yield of the emission was relatively high for a Dy complex (QY = 4 %), [41, 42] and the luminescent lifetime was 50 μs (Figure 5). It is concluded that high concentration of Dy III centers in 1 quenches the luminescence.…”