Si-, Ge-, and Sn-Centered Free Radicals

Lee VY, Sekiguchi A (2005) Si-, Ge-, and Sn-centered free radicals from phantom species to grams-order-scale materials. Eur J Inorg Chem 1209... 

Short-lived Ge-centered free radicals of R3Ge belong to the hypovalent (trivalent) germanium derivatives. In 1953-1957, Gihnan and coworkers , based on the dissociation of hexaphenylethane to free Ph3C radicals, tried to obtain the Ph3Ge radical by dissociation of Ph3GeMPh3 (M = C, Si, Ge, Sn). 

From Free Radicals RR R"E This last synthetic route, involving the one-electron oxidation of the free radicals RR R"E with an appropriate Lewis acid such as PhjC, is one of the best methods for the extremely fast and clean formation of the element-centered cations RR R"E+. Although this approach requires the presence of the radical species as readily available starting materials, the recent synthesis of stable silyl-substituted radicals of the type (r-Bu2MeSi)3E (E = Si, Ge, Sn) (see Section 2.2.4.1.2) made such an approach a rather attractive and easily accessible synthetic route to the stable and free (r-Bu2MeSi)3E+ cations (Scheme 2.6)... 

The chemistry of the heavy analogs of organic free radicals, that is, radicals centered on the Si, Ge, Sn, and Pb atoms, has been thoroughly reviewed several times, particularly that of the silyl radicals. Therefore, in the present review we will briefly bring together the most important discoveries in this field with particular attention paid to the most recent developments and progress, especially in the synthesis of the stable representatives of heavier group 14 elements centered radicals. ... 

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