Hayton Trevor W, Wu Guang
Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara California 93106, USA.
J Am Chem Soc. 2008 Feb 13;130(6):2005-14. doi: 10.1021/ja077538q. Epub 2008 Jan 19.
Addition of 1 equiv of Li(Ar2nacnac) (Ar2nacnac = (2,6-(i)Pr2C6H3)NC(Me)CHC(Me)N(2,6-(i)Pr2C6H3)) to an Et2O suspension of UO2Cl2(THF)3 generates the uranyl dimer [UO2(Ar2nacnac)Cl]2 (1) in good yield. A second species can be isolated in low yield from the reaction mixtures of 1, namely [Li(OEt2)2][UO2(Ar2nacnac)Cl2] (2). The structures of both 1 and 2 have been confirmed by X-ray crystallography. Complex 1 reacts with Ph3PO to generate UO2(Ar2nacnac)Cl(Ph3PO) (3). In addition, 1 reacts with AgOTf and either 1 equiv of DPPMO2 or 2 equiv of Ph2MePO to provide [UO2(Ar2nacnac)(DPPMO2)][OTf] (4) and [UO2(Ar2nacnac)(Ph2MePO)2][OTf] (5), respectively. Both 4 and 5 have been fully characterized, including analysis by X-ray crystallography and cyclic voltammetry. Reduction of 4 with Cp2Co provides UO2(Ar2nacnac)(CH{Ph2PO}2) (6), a uranyl(VI) complex that is generated by the formal loss of H* from the DPPMO2 ligand. Labeling studies have been performed in an attempt to elucidate the mechanism of hydrogen loss. In contrast, reduction of 5 with Cp2Co provides UO2(Ar2nacnac)(Ph2MePO)2 (7), a rare example of a uranyl(V) complex. As expected, the solid-state molecular structure of 7 reveals slightly longer U-O(oxo) bond lengths relative to 5. Furthermore, complex 7 can be converted back into 5 by oxidation with AgOTf in toluene.
向 UO2Cl2(THF)3 的 Et2O 悬浮液中加入 1 当量的 Li(Ar2nacnac)（Ar2nacnac = (2,6-(异丙基)2C6H3)NC(甲基)CHC(甲基)N(2,6-(异丙基)2C6H3)），能以良好的产率生成铀酰二聚体 [UO2(Ar2nacnac)Cl]2 (1)。从 1 的反应混合物中还能以低产率分离出第二种物质，即 [Li(OEt2)2][UO2(Ar2nacnac)Cl2] (2)。1 和 2 的结构均已通过 X 射线晶体学得到证实。配合物 1 与 Ph3PO 反应生成 UO2(Ar2nacnac)Cl(Ph3PO) (3)。此外，1 与 AgOTf 以及 1 当量的 DPPMO2 或 2 当量的 Ph2MePO 反应，分别生成 [UO2(Ar2nacnac)(DPPMO2)][OTf] (4) 和 [UO2(Ar2nacnac)(Ph2MePO)2][OTf] (5)。4 和 5 均已得到全面表征，包括通过 X 射线晶体学分析和循环伏安法。用 Cp2Co 还原 4 得到 UO2(Ar2nacnac)(CH{Ph2PO}2) (6)，这是一种铀酰(VI)配合物，由 DPPMO2 配体形式上失去 H* 生成。已进行标记研究以试图阐明氢损失的机制。相比之下，用 Cp2Co 还原 5 得到 UO2(Ar2nacnac)(Ph2MePO)2 (7)，这是铀酰(V)配合物的一个罕见例子。如预期的那样，7 的固态分子结构显示相对于 5，U - O(氧代)键长略长。此外，配合物 7 可通过在甲苯中用 AgOTf 氧化转化回 5。
