TY - JOUR
T1 - Mixed-metal single-molecule magnets
T2 - Syntheses, structure, and magnetic properties of [Mn8Fe4O12(O2CR) 16(H2O)4] (R = CH2Cl, CH 2Br, CHCl2)
AU - Yang, Chen I.
AU - Yang, Shwu Fen
AU - Hung, Shao Po
AU - Lee, Gene Hsiang
AU - Wur, Ching Shuei
AU - Tsai, Hui Lien
PY - 2011/11/28
Y1 - 2011/11/28
N2 - 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.
AB - 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.
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U2 - 10.1016/j.poly.2011.02.002
DO - 10.1016/j.poly.2011.02.002
M3 - Article
AN - SCOPUS:82255194011
VL - 30
SP - 2969
EP - 2977
JO - Polyhedron
JF - Polyhedron
SN - 0277-5387
IS - 18
ER -