The exchange of the PPh3 ligand in the complex [1,3-bis(2,6-dimethylphenyl)4,5-dihydroimidazol-2-ylidene](PPh3)(Cl)2RuCHPh (7) for a pyridine ligand at ambient temperature leads to the formation of the stable phosphine-free carbene ruthenium complex [1,3-bis(2,6-dimethylphenyl)4,5-dihydroimidazol-2-ylidene](C5H5N)2(Cl)2 RuCHPh (8). The resulted ruthenium complex exhibits highly catalytic activity for the cross metathesis of acrylonitrile with various functionalized olefins under mild conditions, and its activity can be further improved by the addition of a Lewis acid such as Ti(OiPr)4. In the mixture products, the Z-isomer predominates.
在常温下,将[1,3-双(2,6-二甲基苯基)4,5-二氢
咪唑-2-亚基](PPh3)(Cl)2RuCHPh (7)中的 PPh3
配体与
吡啶配体交换,可形成稳定的无
磷碳化
钌配合物[1、3-双(2,6-二甲基苯基)4,5-二氢
咪唑-2-亚基](
C5H5N)2(Cl)2 RuCHPh (8)。生成的
钌络合物对
丙烯腈与各种官能化烯烃在温和条件下的交叉复分解反应具有很强的催化活性,而且通过添加
路易斯酸(如 Ti(OiPr)4),其活性还能得到进一步提高。