Department of Chemistry, University of Science and Technology of China, Jin Zhai Road 96, Hefei, 230026, China.
Dalton Trans. 2012 Feb 28;41(8):2393-8. doi: 10.1039/c2dt11666a. Epub 2011 Dec 23.
The present study revealed a surprising valence transformation of copper (Cu) in the sintering process of mixtures of copper chloride dihydrate (CuCl(2)·2H(2)O) with β-cyclodextrin (β-CD) in ambient atmosphere. Such a transformation in Cu valence states can be modulated by changing the initial molar ratio (IMR) of CuCl(2)·2H(2)O to β-CD in the mixtures. Firstly, as the value of IMR decreased, the content of cuprous chloride (CuCl) decreased, while the content of cupric oxide (CuO) increased gradually. That is to say, there is an unambiguous IMR-dependence of the contents of CuCl and CuO formed. However, such a controllable valence transformation from Cu(II) to Cu(I) to Cu(II) did not happen in nitrogen atmosphere. Secondly, the in situ composite of CuCl and CuO produced a highly ordered structure of self-assembled nanowires, intertwined, with a diameter of 30 to 50 nm. Furthermore, electronic structural analysis provided direct evidence that the Cu-Cl and Cu-O bonds in this composite material were simultaneously impaired by self-assembled growth. Finally, we noticed that the photoluminescence property of CuCl was regulated through the formation of composites with CuO. In addition, this in situ composite synthesis technique was used to modify the magnetic property of CuO. Furthermore, the anomalous ferromagnetic behaviour of the CuO nanocrystal was observed and explained. In short, this work not only demonstrates a flexible and easily controllable valence transformation of Cu, but also provides a novel approach for constructing inorganic nanocomposite materials. We believe that the implications of these findings are important and make significant contributions to the development of inorganic chemistry and material science.
本研究揭示了在环境气氛中，水合二氯化铜（CuCl2·2H2O）与β-环糊精（β-CD）混合物的烧结过程中铜（Cu）令人惊讶的价态转变。通过改变混合物中 CuCl2·2H2O 的初始摩尔比（IMR），可以调节这种 Cu 价态的转变。首先，随着 IMR 值的降低，一氯化铜（CuCl）的含量减少，而氧化铜（CuO）的含量逐渐增加。也就是说，形成的 CuCl 和 CuO 的含量存在明确的 IMR 依赖性。然而，在氮气气氛中，并没有发生从 Cu(II)到 Cu(I)再到 Cu(II)的可控价态转变。其次，CuCl 和 CuO 的原位复合产生了高度有序的自组装纳米线结构，相互交织，直径为 30 至 50nm。此外，电子结构分析提供了直接证据，表明这种复合材料中 Cu-Cl 和 Cu-O 键同时受到自组装生长的破坏。最后，我们注意到 CuCl 的光致发光性质通过与 CuO 形成复合材料得到了调节。此外，还利用这种原位复合合成技术来修饰 CuO 的磁性。进一步观察到并解释了 CuO 纳米晶的异常铁磁性行为。总之，这项工作不仅展示了 Cu 灵活且易于控制的价态转变，还为构建无机纳米复合材料提供了一种新方法。我们相信这些发现的意义重大，为无机化学和材料科学的发展做出了重要贡献。
