首页> 外文期刊>Polyhedron: The International Journal for Inorganic and Organometallic Chemistry >Synthesis, crystal structure and magnetic properties of novel Mn-12 single-molecule magnets with thiophenecarboxylate, [Mn12O12(O2CC4H3S)(16)(H2O)(4)], and its tetraphenylphosphonium salt
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Synthesis, crystal structure and magnetic properties of novel Mn-12 single-molecule magnets with thiophenecarboxylate, [Mn12O12(O2CC4H3S)(16)(H2O)(4)], and its tetraphenylphosphonium salt

机译:新型带噻吩羧酸盐的Mn-12单分子磁体[Mn12O12(O2CC4H3S)(16)(H2O)(4)]及其四苯基phosph盐的合成,晶体结构和磁性

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摘要

The preparation and physical characterization are reported for novel Mn-12 single-molecule magnets having thiophenecarboxylate bridges, [Mn12O12(O2CC4H3S)(16)(H2O)(4)] (1), and its PPh4 salt (2). The reaction of the excess amount of 2-thiophenecarboxylic acid (tpcH) and [Mn12O12(OAc)(16)(H2O)(4)] in CH2Cl2 gave black crystals of 1, which could be reduced by PPh4I to give 2. From the crystal structure analysis of 2, it is revealed that there are two five-coordinated Mn ions, one of which is assigned to a Mn-II ion being in the vicinity of the tetraphenylphosphoniurn cation. Both complexes exhibit out-of-phase a.c. magnetic susceptibility (chi(M)'') signals in the 5.0-6.5 K range at 997 Hz a.c. frequency, which indicate that they are single-molecule magnets. From Arrhenius plots of the frequency dependence of the temperature of the chi(M)'' peaks, the effective energy barriers U-eff were estimated to be 69 and 57 K for high-temperature phases of 1 and 2, respectively, and 40 K for the low-temperature phase of 1. The reduced magnetization measurement and its analysis indicate that 2 has S = 19/2 ground state with g = 1.99 and D = -0.61 K. (C) 2003 Elsevier Science Ltd. All rights reserved. [References: 18]
机译:报道了具有噻吩羧酸盐桥,[Mn12O12(O2CC4H3S)(16)(H2O)(4)](1)及其PPh4盐(2)的新型Mn-12单分子磁体的制备和物理特性。过量的2-噻吩羧酸(tpcH)与[Mn12O12(OAc)(16)(H2O)(4)]在CH2Cl2中的反应产生黑色晶体1,可被PPh4I还原为2。 2的晶体结构分析表明,存在两个五配位的Mn离子,其中一个配属于四苯基膦腈阳离子附近的Mn-II离子。两种络合物均表现出异相的交流电。 997 Hz a.c时在5.0-6.5 K范围内的磁化率(chi(M)'')信号频率,表明它们是单分子磁体。根据chi(M)''峰温度的频率依赖性的Arrhenius曲线,高温相1和2以及40 K的有效能垒U-eff估计分别为69和57 K对于1的低温相。还原磁化强度测量及其分析表明2具有S = 19/2基态,g = 1.99,D = -0.61K。(C)2003 Elsevier ScienceLtd。保留所有权利。 [参考:18]

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