基团 assembly; base group; functional group; radical
取代 displace; replace; substitute for; take over; supersede; supplant 国产货正在取代进口货。 home-made goods are edging out imported foreign goods. 他受了伤, 另一个选手取代了他。 he was hurt, and another player replaced him. 许多职员被计算机取代了。 many employees were displaced by computers
Syntheses of ? ? diimine and 2 - aminopyridine transiting metal complexes bearing 2 , 6 - unsym - substituents on the aryl , and investigation on the steric and electronic effects of the unsym - subatituents on the catalytic property 以2 , 6位不同基团取代的苯胺与相应的二酮反应合成系列的? ?二亚胺和吡啶胺基过渡金属配合物。主要考察芳环2 , 6位基团立体位阻对催化性能的影响,同时也考虑基团的推拉电子效应。