Theoretical determination of the standard enthalpies of formation of alkyl radicals using the concept of a complete set of homodesmotic reactions.

The complete sets of homodesmotic reactions (HDR) for 107 acyclic alkyl free radicals С-С of normal and branched structure were constructed using the graph-theoretic representation and analysis of a tested compound. The absolute enthalpies of the studied compounds and HDR reference structures were calculated using the M062X/cc-pVTZ level of theory. Based on these data, the thermal effects of HDRs were calculated and then applied to determine the standard enthalpies of formation of the studied radicals using the known enthalpies of formation of reference structures.

Interplay of the Ring and Steric Strains in the Highly Substituted Cyclopropanes.

Using the concept of a complete set of homodesmotic reactions for the analysis of molecular energetics of polysubstituted methyl- and fluorocyclopropanes allows assessing the strain energy SE of cyclopropanes, free from interfering effects, in full accordance with the IUPAC definition ("relative to a reference ...