Three mixed-metal single-molecule magnets containing [Mn8Fe 4O12]16+ cores are synthesized and characterized. The reaction of FeCl2·4H2O with KMnO4 and RCOOH (R = CH2Cl, CH2Br) in H 2O gives [Mn8Fe4O12(O 2CR)16(H2O)4] (R = CH2Cl (1), CH2Br (2)) in yields of 43% and 40%, respectively. Treatment of complex 1 with an excess of CHCl2COOH in CH2Cl2 gives [Mn8Fe4O12(O2CCHCl 2)16(H2O)4]·CH 2Cl2·10H2O (3·CH 2Cl2·10H2O) in a yield of 83%. The X-ray structure analysis reveals that all three complexes consist of a trapped-valence dodecanuclear core comprising 4MnIII, 4Fe III, and 4MnIV ions. DC magnetic susceptibility and magnetization measurements indicate that all three complexes exhibit intramolecular antiferromagnetic interaction, resulting in an S = 4 ground state. In addition, frequency-dependent out-of-phase AC magnetic susceptibility signals at low temperature for complexes 1, 2, and 3 are indicative of their single-molecule magnetism behavior.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry