model. Less electron-rich vinyl amides or amines form η2-olefin complexes, but do not isomerize to carbene complexes. Calculated ΔE values for selected ‘‘ competition’’ reactions reveal that donation by both Ru and the heteroatom-substituted X are necessary to make the carbene complex L2HClRuC(X)(CH3) more stable than the olefin complex L2HClRu(η2-H2CCHX). This originates in part from a diminished
RuH 2 Cl 2 L 2 (L = PPr 3 i)的脱卤化氢得到(RuHClL 2)2,通过X射线晶体学显示为卤化物桥连的二聚体。
氟化物类似物也是二聚体。(RuHClL 2)2与N 2,
吡啶和C 2 H 4(L')反应生成RuHClL'L 2,但与
乙烯基醚和
乙烯基酰胺H 2 C CH(E)[E = OR,NRC(O )R'],这样的烯烃键合后异构化为杂原子取代的卡宾配合物L 2 HClRu C(CH 3)(E)。通过DFT(B3PW91)计算,对于作为烯烃的C 2 H 4(发现有吸热性),通过DFT(B3PW91)计算确定了这种重排的反应机理,并针对H 2 C C(H)(OCH 3)计算了中间体的结构)和环状和非环状酰胺取代的烯烃。从实验和计算上都发现,酰胺氧结合到Ru上,对于非环状模型,计算出的结合能约为9 kcal mol -1。少富电子
乙烯基酰胺或胺形成η 2个烯烃配合物,但不