The ease of free-radical hydrogen abstraction from cycloalkanes containing from 5 to 12 carbon atoms is compared with the reactivity of open-chain methylene groups. Activation energies for abstraction from open-chain positions are generally larger than those for all the cycloalkanes studied except cyclohexane. The results are discussed in terms of the release or aggravation of conformational strain upon forming the sp2 radical center and, for the Cs-Ci2 compounds, of the inaccessibility of the C-H bonds toward attack. A recent proposal that the relative ease of forming primary, secondary, and tertiary free radicals is predominantly steric in origin is discussed.

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Infrared and conductance measurements on three Simonini complexes (silver iodine dibenzoates) indicate a symmetrical structure. Ag+ (ArCO2)2I−is considered a limiting constitution, but the substance is an extremely weak electrolyte. The constitution is discussed in terms of the observed chemistry and the stabilizing role of the silver cation.

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