Heczko Michał, Reczyński Mateusz, Näther Christian, Nowicka Beata
Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
Institut für Anorganische Chemie, Christian-Albrechts-Universität, Max-Eyth.-Str. 2, 24118 Kiel, Germany.
Dalton Trans. 2021 Jun 8;50(22):7537-7544. doi: 10.1039/d1dt00367d.
The reaction between [Ni(cyclam)]2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) and [Nb(CN)8]4- in concentrated water solutions of different s-block metal salts leads to the formation of 2-dimensional honeycomb-like coordination networks of the formula Mx[Ni(cyclam)]3[Nb(CN)8]2·nH2O (x = 2: M = Li+, Na+; x = 1: M = Mg2+, Ca2+, Sr2+, Ba2+). The CN-bridged Ni-Nb coordination layers are intersected by channels filled with crystallisation water molecules and guest mono- or di-valent metal cations, which compensate the negative charge of the framework. The structural details and crystal symmetry vary between the networks, depending on the arrangement of the water molecules and the intermolecular interactions enforced by the guest cations. All compounds show long range magnetic order arising from superexchange interactions between paramagnetic NiII (s = 1) and NbIV (s = 1/2) centres through CN-bridges within the layers and weaker inter-layer interactions mediated by H-bonds. The ordering temperature as well as the coercive field of the magnetic hysteresis can be tuned by the type of guest cation, with the highest values achieved for Mg2+ and the lowest for Na+.
在不同s区金属盐的浓水溶液中，[Ni(cyclam)]2+（cyclam = 1,4,8,11-四氮杂环十四烷）与[Nb(CN)8]4-反应生成化学式为Mx[Ni(cyclam)]3[Nb(CN)8]2·nH2O的二维蜂窝状配位网络（x = 2：M = Li+、Na+；x = 1：M = Mg2+、Ca2+、Sr2+、Ba2+）。由CN桥连的Ni-Nb配位层被充满结晶水分子和客体单价或二价金属阳离子的通道所贯穿，这些阳离子补偿了骨架的负电荷。网络之间的结构细节和晶体对称性各不相同，这取决于水分子的排列以及客体阳离子所施加的分子间相互作用。所有化合物都表现出长程磁有序，这是由顺磁性NiII（s = 1）和NbIV（s = 1/2）中心通过层内的CN桥发生的超交换相互作用以及由氢键介导的较弱层间相互作用引起的。磁滞的有序温度以及矫顽场可以通过客体阳离子的类型进行调节，其中Mg2+达到的值最高，Na+达到的值最低。
