Ionothermal synthesis, magnetic transformation and hydration-dehydration properties of Co(II)-based coordination polymers
Ionothermal synthesis, magnetic transformation and hydration-dehydration properties of Co(II)-based coordination polymers
复制标题
Co(II)基配位聚合物的离子热合成、磁转化及水合脱水性能
DOI：
10.1039/c6ra14268k
复制
发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
Zhuang Gui-Lin
中科院分区：
文献类型：
--
作者：
Chen Wen-Xian;Gao Yi-Fen;Gao Pei-Yuan;Liu Qiu-Ping;Zhuang Gui-Lin
两种低配位的配位聚合物，[Co（nip）2][EMIm] 2（1）（H2nip = 5-硝基-烟酸，EMIm = 1-乙基-3-甲基咪唑鎓）和[Co（bptc）][EMIm] 2·H2O（2）在离子液体介质中制备了（H4 bptc = 2，2 '，4，4'-联苯四甲酸），证明了离子交换合成可以作为制备低配位配位聚合物（LCCP）的有力工具。对合成条件的研究表明，较低的反应温度、合适的配体与金属离子的配比以及疏水性离子液体对液晶聚合物的形成具有重要意义。它们都具有有趣的水合-脱水性质，颜色从深紫色可逆地变为粉红色。固体紫外-可见光谱的测量也表明，最大吸附峰在水合作用下发生蓝移。值得注意的是，在水合和脱水过程中，化合物2表现出从反铁磁性到亚铁磁性的磁性转变。从本质上讲，这种转变是由客体水引发的新的传播方式的形成引起的。
Two low-coordinated coordination polymers, [Co(nip)2][EMIm]2 (1) (H2nip = 5-nitryl-isophthalic acid, EMIm = 1-ethyl-3-methyl imidazolium) and [Co(bptc)][EMIm]2·H2O (2) (H4bptc = 2,2′,4,4′-biphenyltetracarboxylic acid) were prepared under an ionic liquid medium, demonstrating that ionothermal synthesis may act as a powerful tool in the preparation of low-coordinated coordination polymers (LCCPs). Investigation on the synthetic conditions shows that a lower reaction temperature, appropriate ratio of ligand to metal ions, and hydrophobic ionic liquid are of key importance for the formation of LCCPs. Both of them feature interesting hydration–dehydration properties with reversible color changing from deep purple to pink. Solid state UV-Vis spectra measurements also indicate that the largest adsorbtion peaks are blue-shifted under hydration. Significantly, under hydration and dehydration processes, compound 2 exhibits a magnetic transformation from anti-ferromagnetism to ferrimagnetism. Essentially, this transformation arises from the formation of new propagating ways triggered by guest water.