Toward Equatorial Planarity about Uranyl: Synthesis and Structure of Tridentate Nitrogen-Donor {UO2}2+ Complexes

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• 作者：Roy Copping ; Byoungseon Jeon ; C. Das Pemmaraju ; Shuao Wang ; Simon J. Teat ; Markus Janousch ; Tolek Tyliszczak ; Andrew Canning ; Niels Gr酶nbech-Jensen ; David Prendergast ; David K. Shuh
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：March 3, 2014
• 年：2014
• 卷：53
• 期：5
• 页码：2506-2515
• 全文大小：368K
• 年卷期：v.53,no.5(March 3, 2014)
• ISSN：1520-510X

文摘

The reaction of UO₂Cl₂路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鈥?b>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鈥?b>3 at the U-4d edges have been recorded using a soft X-ray Scanning Transmission X-ray Microscope (STXM) and reveal the uranium 4d_5/2 and 4d_3/2 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.