Oligonuclear homo- and mixed-valence manganese complexes based on thiophene- or aryl-carboxylate ligation: Synthesis, characterization and magnetic studies
Oligonuclear homo- and mixed-valence manganese complexes based on thiophene- or aryl-carboxylate ligation: Synthesis, characterization and magnetic studies
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DOI：
10.1016/j.ica.2013.03.019
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发表时间：
2013-05-24
影响因子：
2.8
通讯作者：
Janiak, Christoph
中科院分区：
文献类型：
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作者：
Elshaarawy, Reda F. M.;Lan, Yanhua;Janiak, Christoph
混合价三核锰化合物[Mn 3 O（O2 CTh）（6）（L）（x）（H2O）y]中心点n（溶剂）（Th =噻吩，1个中心点CH 3CN：L =吡啶（py），x = 3，y = 0，n = 1，溶剂= CH 3CN; 1个中心点类似于H2O：L = py，x = 3，y = 0，n =类似于1，溶剂= H2O; 2个中心点：L = py，x = 2，y = 1，n = 0.25，溶剂= CH_3CN; 3：L = 3-M_2O，x = 2，y = 1，n = 0），其核为[（MnMn_2 III）-Mn-II（mu（3）-O）]（6+）。四价锰配合物（NBu 4 n）[Mn 4 O2（O2 CAr）（9）（L）]（4中心点ThCO 2 H中心点CH 2Cl 2：Ar = -Th，L = EtOH; 6：Ar = -Ph，L = H2O; 7：Ar = -Ph-p-Me，L = H2O; 8中心点CH 2Cl 2：合成了具有[Mn-4（III）（mu（3）-O）（2）]（8+）核的[（MnMn_3 O_2）-Mn-II-O-III（O_2CTh）（7）（bpy）（2）]（5），并对其结构和磁性进行了表征。化合物1-3是通过Mn-II（O_2CMe）（2）中心点4 H（2）O与（NBu_4 ~ n）（MnO_4）-O-VII在非质子吡啶（1）或非质子/质子吡啶/乙醇（2）或甲醇/乙醇（3）混合溶剂中的歧化反应得到的。簇合物4-8是由Mn-II（O_2CAr）（2）中心点xH（_2）O/ArCOOH与（NBu_4 ~ n）（MnO_4）-O-II在EtOH/CH_3CN中进行歧化反应合成的。含2-噻吩甲酸酯（ThCO_2-）的化合物1个中心点CH_3CN、1个类似于2 H（2）O的中心点和4个中心点ThCO_2 H中心点CH_2Cl_2的X-射线结构表征表明，（O-2）C-C（Th）键周围的噻吩环无序，S原子和相对的（5-）CH基团分别分布在两个环位置上。通过键价和计算和键距计算，可以明确地归属1中近似等腰三角形的[（MnMn 2 III）-Mn-II（mu（3）-O）]（6+）核中的Mn Ⅱ原子。4中心点ThCO_2H中心点CH_2Cl ~-_2和8中心点CH_2Cl ~-_2结构阴离子配合物的[Mn ~（-4）（mu（3）-O）（2）]（8+）核均为Mn ~（-3）氧化态，呈“蝴蝶”状排列。通过变温磁化率和磁化强度的测量研究了4-8的磁性。对于[Mn-4（III）（mu（3）-O）（2）]（8+）蝶形核化合物4、6-8观察到类似的磁性行为，对于Mn-b中心点中心点Mn-b和Mn-b中心点Mn-w耦合，锰离子对之间的反铁磁相互作用具有类似于14.5 cm（-1）和类似于4.6 cm（-1）的振幅，（B =机身，w =机翼）。改变[Mn_4O_2（O_2CAr）（9）（L）]（-）中Ar配体的尺寸对这些蝶形团簇的磁性没有显著影响。(c)2013爱思唯尔有限公司版权所有。
Mixed-valence trinuclear manganese compounds [Mn3O(O2CTh)(6)(L)(x)(H2O)y]center dot n(solvent) (Th = thiophene, 1 center dot CH3CN: L = pyridine (py), x = 3, y = 0, n = 1, solvent = CH3CN; 1 center dot similar to H2O: L = py, x = 3, y = 0, n = similar to 1, solvent = H2O; 2: L = py, x = 2, y = 1, n = 0.25, solvent = CH3CN; 3: L = 3-Mepy, x = 2, y = 1, n = 0) containing a [(MnMn2III)-Mn-II(mu(3)-O)](6+) core have been prepared. Homo-valence tetranuclear manganese complexes (NBu4n)[Mn4O2(O2CAr)(9)(L)] (4 center dot ThCO2H center dot CH2Cl2: Ar = -Th, L = EtOH; 6: Ar = -Ph, L = H2O; 7: Ar = -Ph-p-Me, L = H2O; 8 center dot CH2Cl2: -Ph-3,5-Me-2, no L) with a [Mn-4(III)(mu(3)-O)(2)](8+) core and [(MnMn3O2)-Mn-II-O-III(O2CTh)(7)(bpy)(2)] (5) were synthesized, structurally and magnetically characterized. Compounds 1-3 were obtained by comproportionation of Mn-II(O2CMe)(2)center dot 4H(2)O with (NBu4n) (MnO4)-O-VII in aprotic pyridine (1) or aprotic/protic py/EtOH (2) or Mepy/EtOH (3) solvent mixtures. Clusters 4-8 were synthesized by comproportionation of Mn-II(O2CAr)(2)center dot xH(2)O/ArCOOH with (NBu4n)(MnO4)-O-II in EtOH/CH3CN. X-ray structural characterization of the 2-thiophenecarboxylate (ThCO2-) containing compounds 1 center dot CH3CN, 1 center dot similar to 2H(2)O and 4 center dot ThCO2H center dot CH2Cl2 revealed a thiophene ring disorder about the (O-2)C-C(Th) bond so that the S atom and opposite (5-)CH group are distributed over two ring positions each. The MnII atom in the approximately isosceles triangular [(MnMn2III)-Mn-II(mu(3)-O)](6+) cores in 1 could be clearly assigned from bond valence sum calculations and bond distances. The [Mn-4(mu(3)-O)(2)](8+) core in the anionic complexes in the structures of 4 center dot ThCO2H center dot CH2 Cl-2 and 8 center dot CH2Cl2 has an all Mn-III oxidation level and "butterfly-like" arrangement. The magnetic properties of 4-8 were investigated by variable temperature magnetic susceptibility and magnetization measurements. Similar magnetic behavior was observed for the [Mn-4(III)(mu(3)-O)(2)](8+) butterfly-core compounds 4, 6-8, with antiferromagnetic interactions between pairs of manganese ions with amplitude of similar to 14.5 cm(-1) and similar to 4.6 cm(-1) for the Mn-b center dot center dot center dot Mn-b and Mn-b center dot center dot center dot Mn-w coupling, respectively (b = body, w = wing). Changing the Ar-ligand size in [Mn4O2(O2CAr)(9)(L)](-) does not have a significant effect on the magnetic properties of these butterfly clusters. (c) 2013 Elsevier B.V. All rights reserved.