Sr(NO3)2·DCH18C6配合物晶体结构与辐射稳定性

二环己基-18-冠-6（DCH18C6）可以有效地从高放废液中分离⁹⁰Sr,对于减小放射性废物的危害和实现高放废物的减容有重要意义. 由于在实际应用中DCH18C6处于射线照射下,其结构可能会被破坏并引起络合能力的变化,因此有必要对该配合物的辐射稳定性进行研究. 本文合成了Sr（NO₃）₂·DCH18C6 配合物晶体,并通过单晶X射线衍射（XRD）与扩展X射线吸收精细结构谱（EXAFS）等方法进行了表征,确定Sr²⁺与周围氧原子的配位数为10,Sr―O平均键长约为0.268 nm/0.266 nm（XRD/EXAFS）. 配位原子来自DCH18C6 的六个氧原子以及两个作为双齿配体的硝酸根的四个氧原子. 对该配合物晶体在空气中进行γ辐照,EXAFS结果表明吸收剂量为400 kGy时,Sr―O键长及配位数没有发生变化,配位结构没有被破坏,具有很好的耐辐照稳定性. 显微红外光谱（Micro-FTIR）结果进一步证明辐照后冠醚环的部分C―H 键氧化为羟基或羰基,但并不影响DCH18C6与Sr²⁺的配位结构.

Crystal Structure and Radiation Stability of Sr(NO3)2·DCH18C6 Complex

Dicyclohexano-18-crown-6 ether (DCH18C6) is an efficient extractant for the removal of ⁹⁰Sr from liquid radioactive waste. Because the structure and extractability of DCH18C6 might be affected by radiation during practical application, it is necessary to investigate the radiation stability of the complex ofh Sr²⁺ with DCH18C6. In this work, a single crystal of Sr(NO₃)₂·DCH18C6 complex was synthesized and characterized by X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The coordination number of Sr²⁺ proved to be 10, including six crown ether O atoms and four O atoms from two bidentate nitrate groups. The average Sr―O bond length is 0.268 nm or 0.266 nm, as determined by XRD or EXAFS, respectively. EXAFS spectra proved that the coordination number and the Sr―O bond length of the complex were slightly affected by irradiation for 400 kGy. Although the micro-Fourier-transform infrared spectra indicated that some C―H bonds were oxidized to hydroxyl or carbonyl, the coordination shell of Sr²⁺ and DCH18C6 was not damaged, indicating good radiation stability of the Sr(NO₃)₂·DCH18C6 complex.