modified ex-tended-Hückel theory (MEHT) was used in order to simulate the thermally induced rearrangement of the diene ligand in 3/4. The calculations indicate that there should be a combinational interconversion of both the diene and allyl ligand. A diene inversion becomes energetically favoured, if a simultanous allyl rotation occurs. The transition state 9 lies ca. 90 kJ/mol above the optimized geometry
(η的反应3 -烯丙基)(
环戊二烯基)合
锆(4+)酰
氯与(2,3-二甲基)
镁或(2- phenylbutadiene)
镁,得到(η 3 -烯丙基)(η 4 -缀合的二烯)(cyclopcntadienyl
锆配合物3c和3d。(η/之间的类似反应3 -烯丙基)(
环戊二烯基)
铪(4+)酰
氯与(
丁二烯)
镁,得到(η 3 -烯丙基)(η 4 -
丁二烯)(η 5 -
环戊二烯基)合
铪3e中。配合物3的光解产生了其立体异构体4。开链π在
配体3打开本身朝向顶端Cp配,在4它们两者都以180°扭转。Hf配合物的4 3重排的吉布斯活化能与含Zr的体系的吉布斯活化能没有显着偏离(4c 3e:ΔG ≠ rer。(-10°)= 81.3±1.3 kJ / mol; 4d 3d: Δ ģ ≠(-10°)= 85.7±1.3千焦/摩尔; 4E 3E:Δ ģ ≠(-5℃)= 84.4±1.3千焦/摩尔)。为了模拟热诱导的