Understanding the characteristics of radicals formed from silicon‐containing heavy analogues of alkenes is of great importance for their application in radical polymerization. Steric and electronic substituent effects in compounds such as phosphasilenes not only stabilize the Si=P double bond, but also influence the structure and species of the formed radicals. Herein we report our first investigations of radicals derived from phosphasilenes with Mes, Tip, Dur, and NMe₂ substituents on the P atom, using muon spin spectroscopy and DFT calculations. Adding muonium (a light isotope of hydrogen) to phosphasilenes reveals that: a) the electron‐donor NMe₂ and the bulkiest Tip‐substituted phosphasilenes form several muoniated radicals with different rotamer conformations; b) bulky Dur‐substituted phosphasilene forms two radicals (Si‐ and P‐centred); and c) Mes‐substituted phosphasilene mainly forms one species of radical, at the P centre. These significant differences result from intramolecular substituent effects.

中文翻译：

---

磷腈的自由基化学。

理解由含硅重链烯烃类似物形成的自由基的特性对于其在自由基聚合中的应用非常重要。化合物（例如磷杂烯基化合物）中的立体和电子取代基作用不仅稳定了Si = P双键，而且还影响了所形成自由基的结构和种类。本文中，我们使用muon自旋光谱法和DFT计算报告了对磷原子团在P原子上具有Mes，Tip，Dur和NMe ₂取代基的磷酰基衍生的自由基的首次研究。将磷（氢的轻同位素）添加到磷烯基化合物中可发现：a）电子给体NMe ₂最庞大的Tip取代的磷脂烯形成几个具有不同rotamer构型的muuniated自由基；b）笨重的Dur取代的磷硅烷基形成两个自由基（Si和P中心）；c）甲基取代的磷硅烷基主要在P中心形成一种自由基。这些显着差异是由分子内取代基效应引起的。