Two-electron versus one-electron reduction of chalcogens by uranium(III): synthesis of a terminal U(V) persulfide complex
Two-electron versus one-electron reduction of chalcogens by uranium(III): synthesis of a terminal U(V) persulfide complex
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DOI：
10.1039/c3sc52742e
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发表时间：
2014-01-01
期刊：
影响因子：
8.4
通讯作者：
Mazzanti, Marinella
中科院分区：
文献类型：
--
作者：
Camp, Clement;Antunes, Maria Augusta;Mazzanti, Marinella
三脚架三酰胺基U（III）配合物[U{（SiMe 2NPh）（3）-tacn}]（tacn = 1，4，7-三氮杂环壬烷）1分别与0.0625和0.25当量的HCl反应。以良好的产率分别得到硫桥U（IV）配合物[{U（（SiMe 2NPh）（3）-tacn）}（2）（mu-S）]，2和末端全硫U（V）配合物[U{（SiMe 2NPh）（3）-tacn}（eta（2）-S-2）]，4。在密度泛函理论水平上计算了配合物4的两种不同的电子结构，U（V）过硫化物和U（IV）过硫化物。结果表明，配合物4最好描述为具有显著硫贡献的U（V）过硫化物物种。X射线、磁性和电化学数据支持这一描述。络合物4是末端U（V）过硫化物和S-8被U（III）络合物双电子还原的第一个例子。配合物4在与PPh 3反应时表现为S-原子转移剂，得到过硫化物桥接的二铀（IV）配合物[{U（（SiMe 2NPh）（3）-tacn）}（2）（mu-eta（2）：eta（2）-S-2）]，5，并且S= PPh 3。
The reaction of the tripodal tris-amido U(III) complex [U{(SiMe2NPh)(3)-tacn}] (tacn = 1,4,7-triazacyclononane), 1, with 0.0625 and 0.25 equiv. of elemental sulfur affords the sulfide-bridged U(IV) complex [{U((SiMe2NPh)(3)-tacn)}(2)(mu-S)], 2, and the terminal persulfide U(V) complex [U{(SiMe2NPh)(3)-tacn}(eta(2)-S-2)], 4, respectively, in good yield. Two different electronic structures, U(V) persulfide and U(IV) supersulfide, were computed for complex 4 at the DFT level. The results show that complex 4 is best described as a U(V) persulfide species with a significant sulfur contribution. X-ray, magnetism and electrochemistry data support this description. Complex 4 is the first example of a terminal U(V) persulfide and of a two-electron reduction of S-8 by a U(III) complex. Complex 4 behaves as a S-atom transfer agent when reacted with PPh3, affording the persulfide-bridged diuranium(IV) complex [{U((SiMe2NPh)(3)-tacn)}(2)(mu-eta(2):eta(2)-S-2)], 5, and S=PPh3.