Magnetic Properties of Praseodynium-Organic Framework Containing H2TPPS Ligand

N. Királya, V. Zeleňáka, A. Zeleňákováb, A. Berkutovab, M. Almášia, R. Gyepesc, E. Čižmárb aDepartment of Inorganic Chemistry, P.J. Šafárik University, Moyzesova 11, 041 54 Košice, Slovakia bDepartment of Condensed Matter Physics, P.J. Šafárik University, Park Angelinum 9, 041 54 Košice, Slovakia cDepartment of Inorganic Chemistry, Charles University, Hlavova 2030, 128 43 Prague, Czech Republic

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The presented work is focused on preparation and characterization of Metal-Organic Framework (MOF) with the chemical formula {[Pr4(H2TPPS)3]·nH2O}n. This type of polymer was synthesized via hydrothermal reaction with Pr(NO3)3·6H2O and porphyrinic ligand H2TPPS (where H2TPPS = 4,4',4'',4''-(porphine-5,10,15,20-tetrayl)tetrakisbenzenesulfonate). Prepared MOF was characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermal and elemental analysis, and the magnetic susceptibility measurement. The crystal structure of prepared MOF is formed from Pr(III) ions arranged in 1D chains bridged by four H2TPPS ligands forming the final 3D framework with opening size 4.9×10.4 Å2 and 9.7×5.1 Å2, which are filled with water molecules. The magnetic properties of the coordination polymer were studied by magnetic susceptibility iM(T), and magnetization M(H) measurements in an external dc field up to 7 T in the temperature range from 1.8 to 300 K. The experimental results revealed a significant reduction of the magnetic moment below 50 K as an evidence of the presence of low-lying quasi-doublet in the energy spectrum of Pr ion in {[Pr4(H2TPPS)3]·nH2O}n.

DOI:10.12693/APhysPolA.137.770 topics: praseodymium, porphyrine, metal-organic framework, magnetic properties, spin crossover