A fluorescent EXAFS study on the structure of the solvated cobalt(II) ion and chlorocobalt(II) complexes in hexamethylphosphoric triamide
A fluorescent EXAFS study on the structure of the solvated cobalt(II) ion and chlorocobalt(II) complexes in hexamethylphosphoric triamide
复制标题
六甲基磷三酰胺中溶剂化钴（II）离子和氯钴（II）配合物结构的荧光 EXAFS 研究
DOI：
10.1016/s0020-1693(00)93459-5
复制
发表时间：
1992
影响因子：
2.8
通讯作者：
S. Ishiguro
中科院分区：
文献类型：
--
作者：
K. Ozutsumi;K. Tohji;Y. Udagawa;Y. Abe;S. Ishiguro
用荧光检测修饰的扩展x射线吸收精细结构（EXAFS）研究了六甲基磷酸三酰胺（HMPA）中低浓度（~ 20 mmol dm−3）钴（II）离子及其氯配合物的配位结构。与其他供氧溶剂如水和n， n-二甲基甲酰胺（DMF）不同，钴（II）离子在HMPA中是四配位的。[Co(HMPA) 4]2+、[CoCl(HMPA) 3]+、[CoCl2(HMPA) 2]和[CoCl3(HMPA)]−的CoO （HMPA）键长分别为194(1)、195(1)、194(1)和202(2)pm。CoO键长度明显短于六坐标[Co(H2O)6]2+(208pm)或[Co(dmf)6]2+(206pm)，并且在形成单氯和二氯配合物时几乎保持不变。另一方面，在[CoCl(hmpa)3]+、[CoCl2(hmpa)2]和[CoCl3(hmpa)]−中，CoCl键长分别为224(1)、227(1)和229(1)pm，均明显短于六坐标[CoCl(H2O)5]+中的键长（235 pm）。在这些结构数据的基础上，讨论了钴（II）在HMPA中与DMF中氯络合的热力学行为不同的原因。
The coordination structure of the cobalt(II) ion and its chloro complexes of low concentration (∼20 mmol dm−3) in hexamethylphosphoric triamide (HMPA) has been explored by laboratory EXAFS (extended X-ray absorption fine structure) modified for fluorescence detection. The cobalt(II) ion is four-coordinated in HMPA, unlike other oxygen-donor solvents such as water andN,N-dimethylformamide (DMF). The CoO (HMPA) bond lengths within complexes are revealed to be 194(1), 195(1), 194(1) and 202(2) pm for [Co(hmpa)4]2+, [CoCl(hmpa)3]+, [CoCl2(hmpa)2] and [CoCl3(hmpa)]−, respectively. The CoO bond length is significantly shorter than that within six-coordinate [Co(H2O)6]2+(208 pm) or [Co(dmf)6]2+(206 pm), and remains practically unchanged upon formation of mono- and dichloro complexes. On the other hand, the CoCl bond length is 224(1), 227(1) and 229(1) pm within [CoCl(hmpa)3]+, [CoCl2(hmpa)2] and [CoCl3(hmpa)]−, respectively, all of which are appreciably shorter than that within the six-coordinate [CoCl(H2O)5]+(235 pm). The origin of the different thermodynamic behavior of chloro complexation of cobalt(II) in HMPA from that in DMF will be discussed on the basis of these structural data.