茂基钌化合物的合成与结构研究——双核钌氢化合物的合成与晶体结构研究

The Synthesis and Structure Studies on Cyclopentadienylruthenium Derivatives——The Crystal Structure of [(C_5H_5) Ru (PPh_3)(μ-H)]_2

三氢钌化物[(C_5H_6)Ru(PPh_3)H_3](1)经光解反应生成了一个双核钌氢化合物[(C_5H_5)Ru·(PPh_3)(μ-H)]_2(2)。用X射线重原子法及Fourier迭代解出了2的晶体结构,其分子呈二聚形式,Ru-Ru键处在对称中心,两个钌原子间还通过两个桥氢原子相联。该二聚体的单体为16电子物种,与推测的碳氢键活化反应的中间体类似,为金属有机氢化物活化碳氢键的反应历程提供了证据.文中还给出了2的可能形成过程.

Title compound obtained from light reaction of (C_5H_5)Ru(PPh_3)H_3(1)crystallized in space-group O_4~'-PI with cell dimensions α=0.9828(4), b=1.01107(4), c= 1.39061(6)nm, α=92.59(4), β= 109.95(3), γ=115.76(3)°. The structure was solved by Patterson function and difference Fourier calculations. The dimer molecule of compund 2 possesses point symmetry with the symmetry center on the middle of Ru—Ru bond. Each Ru atom bonded to one Ru atom, one cyclopentadienyl ring, one PPh_3, and two bridged hydride ligands. The monomer form of the dimer is a 16-electron speciea similar to the proposed intermediate in C—H bond activation reaction, θ. g.(C_5Me_5)Ir· (PMe_3). Here the 16-electron species were catched in the dimer form, giving an experimental evidence to the proposed mechanism of C—H bond activation reaction by organometallic hydrides. The possible path for the formation of compound 2 was also suggested.