Fabrication of a novel Eu3+-functionalized Mn-MOF based on the X-type tetracarboxylate ligand for efficient temperature sensing

In this work, by utilizing an X-type tetracarboxylate ligand (1,2,4,5-tetrakis(4-carboxyphenyl)benzene, H₄TCPB), a novel Mn-organic framework, namely, [(CH₃CH₂)₂NH₂]₂[Mn(TCPB)(H₂O)₂] (SQNU-25, SQNU = Shangqiu Normal University), was prepared under a DEF/HAc solm. Due to the structural advantage of SQNU-25, the Ln³⁺ ions (Eu³⁺ and Gd³⁺) have been successfully introduced into the framework by post-synthetic modification. The result of the energy levels of the H₄TCPB ligand and Eu³⁺ ion shows that the H₄TCPB ligand as a chromophore can effectively sensitize Eu³⁺ ions. Moreover, the Eu@SQNU-25 not only shows a typical Eu³⁺ ion red emission but also exhibits good temperature sensing in the wide temperature range (80 to 300 K).