Department of Chemistry, University of California, Berkeley , and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720, United States.
J Am Chem Soc. 2016 Dec 14;138(49):15865-15868. doi: 10.1021/jacs.6b11182. Epub 2016 Dec 1.
The reaction of 3 equiv of Li-CH-2,6-(CH-4-Bu) (Terph-Li) with UI(1,4-dioxane) led to the formation of the homoleptic uranium(III) tris(aryl) complex (Terph)U (1). The U-C bonds are reactive: treatment with excess PrN═C═NPr yielded the double-insertion product [TerphC(NPr)]U(Terph) (2). Complexes 1 and 2 were characterized by X-ray crystallography, which showed that the U-C bond length in 2 (2.624(4) Å) is ∼0.1 Å longer than the average U-C bond length in 1 (2.522(2) Å). Thermal decomposition of 1 yielded Terph-H as the only identifiable product; the process is unimolecular with activation parameters ΔH = 21.5 ± 0.3 kcal/mol and ΔS = -7.5 ± 0.8 cal·mol K, consistent with intramolecular proton abstraction. The protonolysis chemistry of 1 was also explored, which led to the uranium(IV) alkoxide complex U(OCPh)(DME) (3·DME).
当 3 当量的 Li-CH-2,6-(CH-4-Bu)（Terph-Li）与 UI(1,4-dioxane)反应时，生成了同核铀(III)三(芳基)配合物(Terph)U(1)。U-C 键具有反应性：与过量的 PrN═C═NPr 反应生成了双插入产物[TerphC(NPr)]U(Terph)（2）。通过 X 射线晶体学对 1 和 2 进行了表征，结果表明 2 中的 U-C 键长（2.624(4) Å）比 1 中的平均 U-C 键长（2.522(2) Å）长约 0.1 Å。1 的热分解仅生成了 Terph-H 作为唯一可识别的产物；该过程是单分子的，活化参数ΔH = 21.5 ± 0.3 kcal/mol，ΔS = -7.5 ± 0.8 cal·mol K，与分子内质子抽提一致。还探索了 1 的质子亲核取代反应，得到了铀(IV)烷氧基配合物 U(OCPh)(DME)（3·DME）。
