The Me3Si Substituent Effect on the Reactivity of Silanes. Structural Correlations between Silyl Radicals and Their Parent Silanes

Article abstract of DOI:10.1021/jo00038a031

Good linear correlations exist both between the bond dissociation energy of an Si-H bond and the corresponding SiH stretching frequency and between the (29)Si hyperfine splitting of a silicon-centered radical and J((29)Si-H) for the corresponding silane, when the successive substitution at the Si-H function takes place inside a family, i.e., (Me3Si)3-_nSi(H)Me_n, n = 0-3.Explanations for these phenomena are advanced.Such structural correlations allow the characterization of (Me3Si)2Si(H)Me as a radical-based reducing agent with low hydrogen-donating abilities.Rate constants for the reaction of primary alkyl radicals with (Me3Si)2Si(H)Me have been measured over a range of temperatures by using competing unimolecular radical reactions as timing devices.The radical trapping abilities of this silane and other common radical-based reducing agents are compared.