一维配位聚合物中插入肟桥联的Mn <sub>6</sub>团簇,Macromolecules

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一维配位聚合物中插入肟桥联的Mn ₆团簇
Macromolecules ( IF 5.1 ) Pub Date : 2016-08-17 00:00:00 , DOI: 10.1021/acs.macromol.6b01149
Mirela-Fernanda Zaltariov ₁ , Maria Cazacu ₁ , Liviu Sacarescu ₁ , Angelica Vlad ₁ , Ghenadie Novitchi ₂ , Cyrille Train ₂ , Sergiu Shova ₁ , Vladimir B. Arion ₃

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MnCl ₂ ·4H ₂ O与水杨醛肟（H ₂ salox）和1,3-双（羧丙基）四甲基二硅氧烷（H ₂ L）的钠盐按1：1的摩尔比反应导致自组装的{[Mn ₆ O ₂（salox）₆（H ₂ salox）（H ₂ O）₃（μ-L）] H ₂ salox·1.2H ₂ O} _n，是一维配位聚合物，由六水杨酸铝锰酸酯簇作为二级结构单元（SBU）和基于四甲基二硅氧烷的二羧酸酯连接基，即1,3-双（羧丙基）四甲基二硅氧烷组成。该化合物的结构通过单晶X射线衍射确定。中的Mn（III）群集由两个交错μ ₃ -氧代-桥连的Mn ₃肟基的氧原子将三角形连接在一起。由于Jahn–Teller畸变，位于三角形均值平面上方和下方的氧原子的Mn–O距离达到2.5Å。在差示扫描量热法（DSC）曲线中，该化合物在14°C附近显示出玻璃化转变峰。磁化率数据与一组三个簇内反铁磁交换相互作用耦合常数拟合：J ₁ = -0.65 cm ^-1，J ₂ = -1.5 cm ^-1，J ₃ = -0.9 cm ^-1。在2–5 K温度范围内的交流磁化率测量结果显示出频率相关的行为，表明低温下磁化缓慢弛豫。亲液性1,3-双（丙基）四甲基二硅氧烷部分和亲水性极性SBU的共存赋予该结构两亲性。动态光散射（DLS），小角X射线散射（SAXS）以及透射（TEM）和扫描（SEM）电子显微镜检查表明，在二甲基甲酰胺（DMF）中配位聚合物以胶束的形式组织，而在氯仿中则趋向于胶束。形成反胶束和囊泡。

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Oxime-Bridged Mn6 Clusters Inserted in One-Dimensional Coordination Polymer

The reaction of MnCl₂·4H₂O with salicylaldoxime (H₂salox) and the sodium salt of 1,3-bis(carboxypropyl)tetramethyldisiloxane (H₂L) in a 1:1:1 molar ratio led to the self-assembly of {[Mn₆O₂(salox)₆(H₂salox)(H₂O)₃(μ-L)]H₂salox·1.2H₂O}_n, a 1D coordination polymer consisting of hexamanganese(III) salicylaldoximate cluster as secondary building unit (SBU) and tetramethyldisiloxane-based dicarboxylate linker, namely, 1,3-bis(carboxypropyl)tetramethyldisiloxane. The structure of the compound was established by single crystal X-ray diffraction. The Mn(III) clusters consist of two staggered μ₃-oxo-bridged Mn₃ triangles held together by the oxygen atoms of the oxime groups. Because of Jahn–Teller distortion, the Mn–O distances reach 2.5 Å for the oxygen atoms located above and below the triangles mean planes. The compound showed a glass transition peak at around 14 °C in the differential scanning calorimetry (DSC) curve. The magnetic susceptibility data were fitted with a set of three intracluster antiferromagnetic exchange interaction coupling constants: J₁ = −0.65 cm^–1, J₂ = −1.5 cm^–1, and J₃ = −0.9 cm^–1. The ac magnetic susceptibility measurements in the 2–5 K temperature range reveal a frequency-dependent behavior indicative of a slow relaxation of magnetization at low temperature. The coexistence of the lypophilic 1,3-bis(propyl)tetramethyldisiloxane moieties and hydrophilic polar SBUs confers to the structure an amphiphilic character. Dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and transmission (TEM) and scanning (SEM) electron microscopies demonstrate that in dimethylformamide (DMF) the coordination polymer organizes as micelles, whereas in chloroform it tends to form inverse micelles and vesicles.

更新日期：2016-08-17

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