Costa Augusto Iwashita, da Silva Rafaela M R, Botelho Luckerman D G, Coelho Sergio F N, A Sigoli Fernando, Honorato João, Ellena Javier, Martins Felipe T, Gomes Angelo M, Nunes Wallace C, Lloret Francesc, Julve Miguel, Marinho Maria Vanda
Instituto de Química, Universidade Federal de Alfenas, Campus Santa Clara, Alfenas, MG, 37133-840, Brazil.
Instituto de Química, Universidade Estadual de Campinas, Cidade Universitária, Campinas, SP 13083-970, Brazil.
Dalton Trans. 2024 Feb 27;53(9):3994-4004. doi: 10.1039/d3dt03555g.
A three-dimensional terbium(III) coordination polymer of formula [Tb(bttb)(2,5-pzdc)] (1) [Hbttb = 1,2,4,5-tetrakis(4'-carboxyphenyl)benzene and H-2,5-pzdc = 2,5-pyrazinedicarboxylic acid] was obtained under hydrothermal conditions. The bttb tetraanion in 1 adopts the bridging and chelating-bridging pseudo-oxo coordination modes while the 2,5-pzdc dianion exhibits a rather unusual bis-bidentate bridging pseudo-oxo coordination mode, both ligands being responsible for the stiffness of the resulting 3D structure. Solid-state photoluminescent measurements illustrate that 1 exhibits remarkable green luminescence emission, the most intense band occurring in the region of 550 nm (D → F) with lifetimes at the millisecond scale. Thermometric performances of 1 reveal a maximum relative sensitivity () of 0.76% K at 295 K (δ = 0.05 K), constituting a Tb ratiometric solid luminescent thermometer over the physiological temperature range. Variable-temperature static (dc) magnetic susceptibility measurements for 1 in the temperature range 2.0-300 K show the expected behavior for the depopulation of the splitted levels of the F ground state of the magnetically anisotropic terbium(III) ion plus a weak antiferromagnetic interaction through the carboxylate bridges. No significant out-of-phase magnetic susceptibility signals were observed for 1 in the temperature range 2.0-10.0 K, either in the absence or presence of a static dc magnetic field.
