Synthesis, structure and magnetic properties of 2-D and 3-D [cation] {M[Au(CN)2]3} (M = Ni, Co) coordination polymers
Synthesis, structure and magnetic properties of 2-D and 3-D [cation] {M[Au(CN)2]3} (M = Ni, Co) coordination polymers
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DOI：
10.1016/j.poly.2006.10.045
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发表时间：
2007-06-15
期刊：
影响因子：
2.6
通讯作者：
Leznoff, Daniel B.
中科院分区：
文献类型：
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作者：
Lefebvre, Julie;Chartrand, Daniel;Leznoff, Daniel B.
为了研究阳离子的模板效应及其对磁性的影响，进行了M（II）盐与[阳离子][Au（CN）（2）]的反应，得到了一系列形式为[阳离子]{M[Au（CN）（2）]（3）}（阳离子=（Bu 4 N+）-Bu-n，PPN+（双（三苯基膦基）铵）; M = Ni（II）和Co（II））的配位聚合物。（Bu 4 N）-Bu-n{M[Au（CN）（2）]（3）}和PPN{M[Au（CN）（2）]（3）}（M = Ni和Co）的结构包含两个不同的{M[Au（CN）（2）]（3）}（-）的3-D阴离子骨架，因此骨架对阳离子敏感，但对金属中心的身份不敏感。在（Bu 4 N）-Bu-n{M[Au（CN）（2）]（3）}中，金属中心通过[Au（CN）（2）]单元连接，形成六个2-D（4，4）矩形网格，这些网格通过M中心融合，产生复杂的三维框架，该框架容纳（Bu 4 N+）-Bu-n阳离子。在PPN{M[Au（CN）（2）]（3）}中，骨架采用更简单的非互穿普鲁士蓝型伪立方阵列，PPN+阳离子占据每个空腔;尽管阳离子尺寸很大，但维度没有降低。在水的存在下，得到了{Co（H2O）（2）[Au（CN）（2）]（2）}中心点（Bu 4 N）-Bu-n[Au（CN）（2）]，这是一种二维层状聚合物，含有由（Bu 4 N）-Bu-n[Au（CN）（2）]层隔开的{Co（H2O）（2）[Au（CN）（2）]（2）}中性片; 3.4250（13）A的亲金相互作用和氢键连接层。用SQUID磁谱仪研究了所有化合物的磁性。Ni（II）聚合物具有类似的磁性行为，其在低温下由零场分裂和非常弱的反铁磁相互作用主导（D类似于2- 3cm（-1），zJ <1cm（-1））。所有的Co（II）聚合物的磁性行为被发现是非常相似的，并占主导地位的单离子效应（即一个大的一阶轨道贡献）。在这些配位聚合物中没有观察到明显的磁耦合，表明[Au（CN）（2）]桥连单元在这些高维体系中表现为弱的磁交换介体。(c)2006爱思唯尔有限公司保留所有权利。
In order to study the templating effect of the cation and the resulting impact on the magnetic properties, reactions of M(II) salts with [cation][Au(CN)(2)] were conducted, yielding a series of coordination polymers of the form [cation]{M[Au(CN)(2)](3)} (cation = (Bu4N+)-Bu-n, PPN+ (bis(triphenylphosphoranylidene)ammonium); M = Ni(II) and Co(II)). The structures of (Bu4N)-Bu-n{M[Au(CN)(2)](3)} and PPN{M[Au(CN)(2)](3)} (M = Ni and Co) contain two distinct 3-D anionic frameworks of {M[Au(CN)(2)](3)}(-), hence the framework was sensitive to the cation, but not to the identity of the metal center. In (Bu4N)-Bu-n{M[Au(CN)(2)](3)}, the metal centers are connected by [Au(CN)(2)] units to form six 2-D (4, 4) rectangular grids that are fused through the M centers to yield a complex three-dimensional framework which accommodates the (Bu4N+)-Bu-n cations. In PPN{M[Au(CN)(2)](3)}, the framework adopts a simpler non-interpenetrated Prussian-blue-type pseudo-cubic array, with the PPN+ cations occupying each cavity; no reduction in dimensionality occurs despite the large cation size. In the presence of water, {Co(H2O)(2)[Au(CN)(2)](2)} center dot (Bu4N)-Bu-n[Au(CN)(2)] was obtained, a 2-D layered polymer that contains neutral sheets of {Co(H2O)(2)[Au(CN)(2)](2)} which are separated by (Bu4N)-Bu-n[Au(CN)(2)] layers; aurophilic interactions of 3.4250(13) A and hydrogen-bonding connect the layers. The magnetic properties of all compounds were investigated by SQUID magnetometry. The Ni(II) polymers have similar magnetic behaviour, which are dominated by zero-field splitting with very weak antiferromagnetic interactions at low temperature (D similar to 2-3 cm(- 1), zJ < 1 cm(-1)). The magnetic behaviour of all of the Co(II) polymers were found to be very similar, and dominated by single-ion effects (i.e. a large first-order orbital contribution). No significant magnetic coupling is observed in any of these coordination polymers, suggesting that the [Au(CN)(2)] bridging unit behaves as a poor mediator of magnetic exchange in these high-dimensionality systems. (c) 2006 Elsevier Ltd. All rights reserved.