Castro-Rodriguez Ingrid, Nakai Hidetaka, Zakharov Lev N, Rheingold Arnold L, Meyer Karsten
Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, CA 92093, USA.
Science. 2004 Sep 17;305(5691):1757-9. doi: 10.1126/science.1102602.
The electron-rich, six-coordinate tris-aryloxide uranium(III) complex [((AdArO)3tacn)U(III)] [where (AdArOH)3tacn = 1,4,7-tris(3-adamantyl-5-tert-butyl-2-hydroxybenzyl)1,4,7-triazacyclononane] reacts rapidly with CO2 to yield [((AdArO)3tacn)U(IV)(CO2)], a complex in which the CO(2) ligand is linearly coordinated to the metal through its oxygen atom (eta1-OCO). The latter complex has been crystallographically and spectroscopically characterized. The inequivalent O-C-O bond lengths [1.122 angstroms (A) for the O-C bond adjacent to uranium and 1.277 A for the other], considered together with magnetization data and electronic and vibrational spectra, support the following bonding model: U(IV)=O=C*-O- <--> U(IV)-OC-O-. In these charge-separated resonance structures, the uranium center is oxidized to uranium(IV) and the CO2 ligand reduced by one electron.
富电子的六配位三芳氧基铀（III）配合物[((AdArO)3tacn)U(III)] [其中(AdArOH)3tacn = 1,4,7 - 三（3 - 金刚烷基 - 5 - 叔丁基 - 2 - 羟基苄基）-1,4,7 - 三氮杂环壬烷]与二氧化碳迅速反应生成[((AdArO)3tacn)U(IV)(CO2)]，该配合物中CO2配体通过其氧原子以直线型方式与金属配位（η1 - OCO）。后一种配合物已通过晶体学和光谱学进行了表征。不等价的O - C - O键长[与铀相邻的O - C键为1.122埃（Å），另一个为1.277 Å]，结合磁化数据以及电子和振动光谱，支持以下键合模型：U(IV)=O=C* - O - <--> U(IV) - OC - O - 。在这些电荷分离的共振结构中，铀中心被氧化为铀（IV），CO2配体获得一个电子被还原。
