Chemistry and Chemical Engineering, Nanjing National Lab of Microstructure, Nanjing University, Nanjing 210093, P.R. China.
Chemistry. 2012 Jul 27;18(31):9534-42. doi: 10.1002/chem.201201124. Epub 2012 Jun 26.
A new layered metal-organic hybrid compound, namely, [Co(3)(μ(3 -OH)(2)(BTP)(2)] (1; BTP=4-(3-bromothienyl)phosphonate), is reported. The inorganic layer can be viewed as a pseudo-Kagomé lattice composed of corner-sharing irregular triangles of Co(3) (μ(3)-OH), with the cavities filled with the PO(3) groups. The interlayer space is occupied by the 3-bromothienyl groups of BTP(2-). The bulk sample of compound 1 experiences a long-range ferromagnetic ordering below 30.5 K, with a coercivity (H(c)) of 5.04 kOe at 5 K. A systematic study on the size-dependent magnetic coercivity of 1 reveals that the coercivity of 1 increases with reduced particle size from the micrometer to the nanometer scale. When the particle size is about 50-200 nm, the coercivity reaches 24.2 kOe at 5 K. The results demonstrate that compound 1 can vary from a soft magnet to one of the hardest molecule-based magnets, simply by reducing the particle size to nanoscale region.
一种新的层状金属-有机杂化化合物，即[Co(3)(μ(3 -OH)(2)(BTP)(2)]（1；BTP=4-(3-溴噻吩基)膦酸），被报道。无机层可以看作是由 Co(3)(μ(3)-OH)的不规则三角形角共享组成的拟 Kagomé 晶格，其中有空腔填充 PO(3)基团。BTP(2-)的 3-溴噻吩基占据了层间空间。化合物 1 的块状样品在 30.5 K 以下经历长程铁磁有序，在 5 K 时的矫顽力（H(c)）为 5.04 kOe。对 1 的尺寸相关磁矫顽力的系统研究表明，矫顽力随着从微米到纳米尺度的颗粒尺寸减小而增加。当颗粒尺寸约为 50-200 nm 时，在 5 K 时矫顽力达到 24.2 kOe。结果表明，通过将颗粒尺寸减小到纳米级区域，化合物 1 可以从软磁体变为最硬的基于分子的磁体之一。
