Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
Inorg Chem. 2010 Jan 4;49(1):199-208. doi: 10.1021/ic901741n.
The syntheses, crystal structures, and magnetochemical characterization are reported for two new Mn clusters, [Mn(7)O(3)(OH)(3)(O(2)CBu(t))(7)(dmhmp)(4)] (1) and [Mn(12)O(7)(OH)(OMe)(2)(O(2)CPh)(12)(dmhmp)(4)(H(2)O)] (2). They were obtained from the use of 2-(pyridine-2-yl)propan-2-ol (dmhmpH), a more bulky version of the 2-(hydroxymethyl)pyridine (hmpH) reagent commonly employed previously in Mn chemistry. The reaction of dmhmpH with MnCl(2).4H(2)O and NaO(2)CBu(t) in MeCN/MeOH led to the heptanuclear complex 1, whereas the analogous reaction with Mn(O(2)CPh)(2) gave dodecanuclear complex 2. Complexes 1 and 2 are both mixed-valent and are of unprecedented structural types. Complex 1 (Mn(II), 6Mn(III)) can be described as the fusion of butterfly-like [Mn(4)(mu(3)-O)(2)] and tetrahedral [Mn(4)(mu(4)-O)] units by the sharing of a common Mn atom. Complex 2 (3Mn(II), 9Mn(III)) possesses a central [Mn(4)O(6)] face-sharing incomplete dicubane, on either side of which is a tetrahedral [Mn(4)(mu(4)-O)] unit attached to the oxide ions of the former. Solid-state dc and ac magnetic susceptibility measurements on 1 and 2 establish that they possess unusual S = 7/2 and 13/2 ground states, respectively. The ac susceptibility studies on 2 revealed nonzero frequency-dependent out-of-phase (chi(M)'') signals at temperatures below 3 K, indicating a single-molecule magnet (SMM). Magnetization versus applied dc field sweeps on single crystals of 2.3CH(2)Cl(2) down to 0.04 K exhibited hysteresis, thus confirming complex 2 to be a new half-integer SMM.
本文报道了两个新的 Mn 簇合物[Mn(7)O(3)(OH)(3)(O(2)CBu(t))(7)(dmhmp)(4)]（1）和[Mn(12)O(7)(OH)(OMe)(2)(O(2)CPh)(12)(dmhmp)(4)(H(2)O)]（2）的合成、晶体结构和磁化学特性。它们是通过使用 2-(吡啶-2-基)丙烷-2-醇（dmhmpH），一种比之前在 Mn 化学中常用的 2-(羟甲基)吡啶（hmpH）试剂更大体积的试剂，得到的。dmhmpH 与 MnCl(2).4H(2)O 和 NaO(2)CBu(t)在 MeCN/MeOH 中的反应生成了七核配合物 1，而类似的反应与 Mn(O(2)CPh)(2)反应则得到十二核配合物 2。配合物 1 和 2 均为混合价态，具有前所未有的结构类型。配合物 1（Mn(II), 6Mn(III))可以描述为通过共享一个共同的 Mn 原子，将蝴蝶状的[Mn(4)(mu(3)-O)(2)]和四面体形的[Mn(4)(mu(4)-O)]单元融合在一起。配合物 2（3Mn(II), 9Mn(III))具有一个中心[Mn(4)O(6)]面共享不完整的双立方烷，在其每一侧都有一个四面体形的[Mn(4)(mu(4)-O)]单元连接到前一个氧化物离子上。1 和 2 的固态直流和交流磁化率测量表明，它们分别具有不寻常的 S = 7/2 和 13/2 基态。2 的交流磁化率研究表明，在低于 3 K 的温度下，存在非零频率相关的反相（chi(M)'')信号，表明存在单分子磁体（SMM）。2.3CH(2)Cl(2)单晶在 0.04 K 以下的磁化强度对施加的直流磁场的扫描显示出滞后现象，从而证实配合物 2 是一种新的半整数 SMM。
