Copping Roy, Jeon Byoungseon, Pemmaraju C Das, Wang Shuao, Teat Simon J, Janousch Markus, Tyliszczak Tolek, Canning Andrew, Grønbech-Jensen Niels, Prendergast David, Shuh David K
Chemical Sciences Division, The Glenn T. Seaborg Center, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Inorg Chem. 2014 Mar 3;53(5):2506-15. doi: 10.1021/ic4026359. Epub 2014 Feb 14.
The reaction of UO2Cl2·3THF with the tridentate nitrogen donor ligand 2,6-bis(2-benzimidazolyl)pyridine (H2BBP) in pyridine leads to the formation of three different complexes: [(UO2)(H2BBP)Cl2] (1), [(UO)2(HBBP)(Py)Cl] (2), and [(UO2)(BBP)(Py)2] (3) after successive deprotonation of H2BBP with a strong base. Crystallographic determination of 1-3 reveals that increased charge through ligand deprotonation and displacement of chloride leads to equatorial planarity about uranyl as well as a more compact overall coordination geometry. Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectra of 1-3 at the U-4d edges have been recorded using a soft X-ray Scanning Transmission X-ray Microscope (STXM) and reveal the uranium 4d5/2 and 4d3/2 transitions at energies associated with uranium in the hexavalent oxidation state. First-principles Density Functional Theory (DFT) electronic structure calculations for the complexes have been performed to determine and validate the coordination characteristics, which correspond well to the experimental results.
在吡啶中，二氧化铀二氯三氢呋喃（UO2Cl2·3THF）与三齿氮供体配体2,6-双（2-苯并咪唑基）吡啶（H2BBP）反应，经过用强碱对H2BBP进行连续去质子化后，生成了三种不同的配合物：[(UO2)(H2BBP)Cl2]（1）、[(UO)2(HBBP)(Py)Cl]（2）和[(UO2)(BBP)(Py)2]（3）。对1 - 3进行晶体学测定表明，通过配体去质子化和氯离子取代增加电荷，导致铀酰周围的赤道平面性以及整体配位几何结构更加紧凑。使用软X射线扫描透射X射线显微镜（STXM）记录了1 - 3在U - 4d边缘的近边X射线吸收精细结构（NEXAFS）光谱，揭示了在与六价氧化态铀相关的能量处的铀4d5/2和4d3/2跃迁。已对这些配合物进行了第一性原理密度泛函理论（DFT）电子结构计算，以确定并验证配位特性，计算结果与实验结果吻合良好。
