TY - JOUR
T1 - Crystal packing effects within [MnIII3O]7+ single-molecule magnets
T2 - Controlling intermolecular antiferromagnetic interactions
AU - Yang, Chen I.
AU - Cheng, Kai Hung
AU - Hung, Shao Po
AU - Nakano, Motohiro
AU - Tsai, Hui Lien
N1 - Funding Information:
The magnetic measurements were obtained from SQUID (MPMS XL-7) at National Sun Yat-Sen University. We thank the National Science Council of Taiwan for financial support under Grant NSC 99-2113-M-006-003-MY3 .
PY - 2011/11/28
Y1 - 2011/11/28
N2 - The reactions of 2-hydroxyphenylethanone oxime (Me-H2salox) and (2-hydroxy-phenyl)-phenyl-methanone oxime (Ph-H2salox) with Mn(ClO4)2·6H2O in MeOH afford trinuclear manganese complexes of [Mn3O(Me-salox)3(MeOH) 3(ClO4)]·MeOH (1·MeOH) and [Mn 3O(Ph-salox)3(MeOH)3(ClO4)] ·2MeOH (2·2MeOH), respectively. X-ray analysis shows that both complexes contain a manganese triangle core, [MnIII 3O]7+. The structural distortion from the twisting of the oxime ligands dominates the ferromagnetic interactions within the three Mn ions in both compounds and results in an S = 6 ground state. The frequency dependence of out-of-phase signals in the alternating current (AC) magnetic susceptibility measurements and the temperature-dependent and sweep-rate-dependent hysteresis loops are indicative of single-molecule magnet behavior. Moreover, both complexes show step-wise magnetization, indicating the occurrence of quantum tunneling of magnetization (QTM). Interestingly, a tail to tail arrangement in the crystal packing of complex 1·MeOH results in strong intermolecular H-bonding interactions and leads to the exchange-bias effect from the antiferromagnetic interaction between the adjacent Mn3 molecules. In contract, QTM steps of complex 2·2MeOH show an absence of the exchange-bias effect due to a weak intermolecular interaction from a head to tail arrangement.
AB - The reactions of 2-hydroxyphenylethanone oxime (Me-H2salox) and (2-hydroxy-phenyl)-phenyl-methanone oxime (Ph-H2salox) with Mn(ClO4)2·6H2O in MeOH afford trinuclear manganese complexes of [Mn3O(Me-salox)3(MeOH) 3(ClO4)]·MeOH (1·MeOH) and [Mn 3O(Ph-salox)3(MeOH)3(ClO4)] ·2MeOH (2·2MeOH), respectively. X-ray analysis shows that both complexes contain a manganese triangle core, [MnIII 3O]7+. The structural distortion from the twisting of the oxime ligands dominates the ferromagnetic interactions within the three Mn ions in both compounds and results in an S = 6 ground state. The frequency dependence of out-of-phase signals in the alternating current (AC) magnetic susceptibility measurements and the temperature-dependent and sweep-rate-dependent hysteresis loops are indicative of single-molecule magnet behavior. Moreover, both complexes show step-wise magnetization, indicating the occurrence of quantum tunneling of magnetization (QTM). Interestingly, a tail to tail arrangement in the crystal packing of complex 1·MeOH results in strong intermolecular H-bonding interactions and leads to the exchange-bias effect from the antiferromagnetic interaction between the adjacent Mn3 molecules. In contract, QTM steps of complex 2·2MeOH show an absence of the exchange-bias effect due to a weak intermolecular interaction from a head to tail arrangement.
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U2 - 10.1016/j.poly.2011.05.030
DO - 10.1016/j.poly.2011.05.030
M3 - Article
AN - SCOPUS:82255162959
SN - 0277-5387
VL - 30
SP - 3272
EP - 3278
JO - Polyhedron
JF - Polyhedron
IS - 18
ER -