Ph(3)P═CH(2) to the U(III) tris(amide) U(NR(2))(3) (R = SiMe(3)) generates a mixture of products from which the U(IV) complex U═CHPPh(3)(NR(2))(3) (2) can be obtained. Complex 2 features a short U═C bond and represents a rare example of a uranium carbene. In solution, 2 exists in equilibrium with the U(IV) metallacycle U(CH(2)SiMe(2)NR)(NR(2))(2) and free Ph(3)P═CH(2). Measurement of this equilibrium as a function
将 Wittig 试剂 Ph(3)P=CH(2) 添加到 U(III) 三(酰胺) U(NR(2))(3) (R = SiMe(3)) 中生成产物混合物,其中可以得到U(IV)络合物U=CHPPh(3)(NR(2))(3) (2)。配合物 2 具有短的 U=C 键,代表了
铀卡宾的罕见例子。在溶液中,2 与 U(IV)
金属环 U(CH(2)SiMe(2)NR)(NR(2))(2) 和游离 Ph(3)P=CH(2) 处于平衡状态。作为温度函数的这种平衡的测量提供 ΔH(rxn) = 11 kcal/mol 和 ΔS(rxn) = 31 eu。此外,使用 DFT 分析研究了 U=C 键的电子结构。