by e.s.r. spectroscopy. Most of the radicals have been generated by photolysis of the bivalent Group 4 species MR, M(NR′2)2 or M(NR′R″)2 when available; others have been obtained by alternative photochemical experiments. The e.s.r. parameters indicate that the radicals have non-planar structures similar to those of analogous transient species such as MMe3˙. The mechanism of formation of the radicals
一些通式MR的溶液稳定物种的3 ˙[R = CH(森达3)2:M =的Si。哥 或Sn],M(NR' 2)3 ˙和M(NR'R“)3 ˙(R'=森达3,R”=
CME 3,M = Ge或Sn)的已经制备和表征通过ESR光谱。大多数基团的已被二价的光解产生的第4族物种MR,M(NR' 2)2或M(NR'R“)2时可用; 其他通过替代的光
化学实验获得。esr参数表明这些基团具有类似于类似瞬态物质(如
MMe)的非平面结构3 ˙。讨论在形成自由基的机制:其不寻常的稳定性(例如SNR 3 ˙具有的半衰期CA 1年20℃)主要归因于空间位阻的二聚化。