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Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Iron(iii) complexes of 2-methyl-6-(pyrimidin-2-yl-hydrazonomethyl)-phenol as spin-crossover molecular materials
Juan Yuan1, Mei-Jiao Liu2, Cai-Ming Liu3
1Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China. kouhz@mail.tsinghua.edu.cn and School of Pharmacy, Henan University of Traditional Chinese Medicine, Zhengzhou 450046, P. R. China.
Abstract:
Four new mononuclear Fe(iii) complexes 1-4 of 2-methyl-6-(pyrimidin-2-yl-hydrazonomethyl)-phenol (H2L) have been synthesized and characterized by magnetic susceptibility measurements and single-crystal X-ray diffraction analysis. Complexes 1-3 are ionic compounds with the formula [Fe(HL)2]X·nsolvent (X = ClO4- (1), BF4- (2) and Cl- (3)), while complex 4 ([Fe(HL)(L)]) is neutral. The central Fe(iii) ion in complexes 1-4 is coordinated by four nitrogen and two oxygen atoms of two Schiff base ligands HL- or L2-, and the coordination geometries of FeIII are all distorted octahedral. Magnetic measurements indicate that complex 1 shows an abrupt spin transition with a thermal hysteresis of 32 K (T1/2↓ = 158 K and T1/2↑ = 190 K), and complex 4 exhibits a gradual incomplete spin transition. Complexes 2 and 3 are high spin with a room-temperature χmT value of 4.32 cm3 K mol-1 and 4.39 cm3 K mol-1, respectively.
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