Monomeric, trimeric, and tetrameric transition metal complexes (Mn, Fe, Co) containing N,N-bis(2-pyridylmethyl)-2-aminoethanol/-ate: preparation, crystal structure, molecular magnetism and oxidation catalysis.
Monomeric, trimeric, and tetrameric transition metal complexes (Mn, Fe, Co) containing N,N-bis(2-pyridylmethyl)-2-aminoethanol/-ate: preparation, crystal structure, molecular magnetism and oxidation catalysis.
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DOI：
10.1039/c1dt10028a
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发表时间：
2011-05
影响因子：
4
通讯作者：
J. Shin;Sankara Rao Rowthu;M. Hyun;Young Joo Song;Cheal Kim;B. Kim;K. Min
中科院分区：
文献类型：
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作者：
J. Shin;Sankara Rao Rowthu;M. Hyun;Young Joo Song;Cheal Kim;B. Kim;K. Min
N,N-双(2-吡啶甲基)-2-氨基乙醇 (bpaeOH)、NaSCN/NaN(3) 和金属 (M) 离子 [M = Mn(II)、Fe(II/III)、Co(II)] 在 MeOH 中反应，可分离出一系列单体、三聚体和四聚体金属配合物，即 [Mn(bpaeOH)(NCS)(2)] (1)， [Mn(bpaeO)(N(3))(2)] (2)、[Fe(bpaeOH)(NCS)(2)] (3)、[Fe(4)(bpaeO)(2)(CH(3)O)(2)(N(3))(8)] (4)、[Co(bpaeOH)(NCS)(2)] (5)，以及[Co(3)(bpaeO)(2)(NO(3))(N(3))(4)](NO(3)) (6)。这些化合物已通过单晶 X 射线衍射和磁化学进行了研究。在配合物 1 中，Mn(II) 与一个 bpaeOH 和两个硫氰酸根离子键合，而在配合物 2 中，它与去质子化的 bpaeO(-) 和两个叠氮化物离子配位。锰离子的氧化态分别为 1 的 2+ 和 2 的 3+，表明不同的氧化态取决于结合阴离子的类型。具有两个硫氰酸根离子的单体铁(II)和钴(II)配合物3和5的结构与1同晶。化合物1、2、3和5在5至300 K的温度范围内表现出高自旋态。4在不对称单元中包含两种不同的铁(III)离子，其中一种与去质子化的bpaeO(-)、叠氮离子和一个甲氧基，另一个与来自bpaeO(-)和甲氧基的三个叠氮离子和两个氧键合。 4中的两个独立的铁(III)离子通过对称形成四核络合物。图 4 显示了铁 (III) 离子之间的铁磁和反铁磁耦合（J = 9.8 和 -14.3 cm(-1)）。 6是混合价三核钴配合物，其公式为Co(III)(S = 0)-Co(II)(S = 3/2)-Co(III)(S = 0)。室温下的有效磁矩对应于高自旋钴(II)离子(∼4.27 μ(B))。有趣的是，6对各种烯烃和醇表现出高效的催化活性，产率适中至优异，并且有人提出高价Co(V)-氧代物质可能负责烯烃环氧化和醇氧化反应中的氧原子转移。
The reaction of N,N-bis(2-pyridylmethyl)-2-aminoethanol (bpaeOH), NaSCN/NaN(3), and metal (M) ions [M = Mn(II), Fe(II/III), Co(II)] in MeOH, leads to the isolation of a series of monomeric, trimeric, and tetrameric metal complexes, namely [Mn(bpaeOH)(NCS)(2)] (1), [Mn(bpaeO)(N(3))(2)] (2), [Fe(bpaeOH)(NCS)(2)] (3), [Fe(4)(bpaeO)(2)(CH(3)O)(2)(N(3))(8)] (4), [Co(bpaeOH)(NCS)(2)] (5), and [Co(3)(bpaeO)(2)(NO(3))(N(3))(4)](NO(3)) (6). These compounds have been investigated by single crystal X-ray diffractometry and magnetochemistry. In complex 1 the Mn(II) is bonded to one bpaeOH and two thiocyanate ions, while in complex 2 it is coordinated to a deprotonated bpaeO(-) and two azide ions. The oxidation states of manganese ions are 2+ for 1 and 3+ for 2, respectively, indicating that the different oxidation states depend on the type of binding anions. The structures of monomeric iron(II) and cobalt(II) complexes 3 and 5 with two thiocyanate ions are isomorphous to that of 1. Compounds 1, 2, 3, and 5 exhibit high-spin states in the temperature range 5 to 300 K. 4 contains two different iron(III) ions in an asymmetric unit, one is coordinated to a deprotonated bpaeO(-), an azide ion, and a methoxy group, and the other is bonded to three azide ions and two oxygens from bpaeO(-) and a methoxy group. Two independent iron(III) ions in 4 form a tetranuclear complex by symmetry. 4 displays both ferromagnetic and antiferromagnetic couplings (J = 9.8 and -14.3 cm(-1)) between the iron(III) ions. 6 is a mixed-valence trinuclear cobalt complex, which is formulated as Co(III)(S = 0)-Co(II)(S = 3/2)-Co(III)(S = 0). The effective magnetic moment at room temperature corresponds to the high-spin cobalt(II) ion (∼4.27 μ(B)). Interestingly, 6 showed efficient catalytic activities toward various olefins and alcohols with modest to excellent yields, and it has been proposed that a high-valent Co(V)-oxo species might be responsible for oxygen atom transfer in the olefin epoxidation and alcohol oxidation reactions.