TY - JOUR
T1 - Synthesis, structures and magnetic properties of two hexanuclear complexes
AU - Yang, Chen I.
AU - Cheng, Kai Hung
AU - Nakano, Motohiro
AU - Lee, Gene Hsiang
AU - Tsai, Hui Lien
N1 - Funding Information:
The magnetic measurements were obtained from the SQUID magnetometer (MPMS XL-7) in NSYSU, and we thank the National Science Council of Taiwan (NSC-96-2113-M-006-010-MY3) for financial support.
PY - 2009/6/22
Y1 - 2009/6/22
N2 - The reaction of salicylaldoxime (H2salox) with Mn(ClO4)2 · 6H2O, NaN(CN)2 and NEt3 in MeOH affords a MnIII6 hexanuclear complex of [Mn6O2(salox)6(MeOH)6(NCNCONH2)2] (1), while reaction of H2salox with MnCl2 · 4H2O and NEt4OH in EtOH affords a MnIII6 hexanuclear complex of [Mn6O2(salox)6(EtOH)4(H2O)2Cl2] (2). Both complexes 1 and 2 contain a [MnIII6(μ3-O)2]14+ core, which is a known structural type in the family of Mn6 complexes. Variable temperature magnetic susceptibilities and magnetization measurement of complexes 1 and 2 have been carried out. Exchange interactions of metal centers for complexes 1 and 2 are fitted by a full diagonalization matrix method. The fitting results indicate that both complexes 1 and 2 have the ground-state spin value of S = 4, and the ground state of complex 1 has the much closer energy to low-lying spin states than that of complex 2. Magnetization measurements at 2.0-4.0 K and 10-70 kG confirm that the ground state is S = 4, with significant magnetoanisotropy as gauged by the D value of -0.82 cm-1 and -1.18 cm-1, for 1 and 2, respectively. The frequency dependence of the out-of-phase component in alternating current magnetic susceptibilities for both complexes 1 and 2 indicates the slow magnetic relaxation of superparamagnetic behaviour with a Ueff of 27.0(1) K and τ0 = 3.8(2) × 10-9 s for complex 1, and Ueff of 25.1(6) K and τ0 = 4.6(1) × 10-8 s for complex 2.
AB - The reaction of salicylaldoxime (H2salox) with Mn(ClO4)2 · 6H2O, NaN(CN)2 and NEt3 in MeOH affords a MnIII6 hexanuclear complex of [Mn6O2(salox)6(MeOH)6(NCNCONH2)2] (1), while reaction of H2salox with MnCl2 · 4H2O and NEt4OH in EtOH affords a MnIII6 hexanuclear complex of [Mn6O2(salox)6(EtOH)4(H2O)2Cl2] (2). Both complexes 1 and 2 contain a [MnIII6(μ3-O)2]14+ core, which is a known structural type in the family of Mn6 complexes. Variable temperature magnetic susceptibilities and magnetization measurement of complexes 1 and 2 have been carried out. Exchange interactions of metal centers for complexes 1 and 2 are fitted by a full diagonalization matrix method. The fitting results indicate that both complexes 1 and 2 have the ground-state spin value of S = 4, and the ground state of complex 1 has the much closer energy to low-lying spin states than that of complex 2. Magnetization measurements at 2.0-4.0 K and 10-70 kG confirm that the ground state is S = 4, with significant magnetoanisotropy as gauged by the D value of -0.82 cm-1 and -1.18 cm-1, for 1 and 2, respectively. The frequency dependence of the out-of-phase component in alternating current magnetic susceptibilities for both complexes 1 and 2 indicates the slow magnetic relaxation of superparamagnetic behaviour with a Ueff of 27.0(1) K and τ0 = 3.8(2) × 10-9 s for complex 1, and Ueff of 25.1(6) K and τ0 = 4.6(1) × 10-8 s for complex 2.
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U2 - 10.1016/j.poly.2009.02.001
DO - 10.1016/j.poly.2009.02.001
M3 - Article
AN - SCOPUS:66149168560
SN - 0277-5387
VL - 28
SP - 1842
EP - 1851
JO - Polyhedron
JF - Polyhedron
IS - 9-10
ER -