Attractive and repulsive effects in the interactions between electron-rich and electron-deficient groups in peri-substituted naphthalenes

Abstract

The 1,5 Me2N ⋯ C(sp2) separations in a series of peri-substituted naphthalene derivatives are sensitive to the through-space electron-attracting power of the carbon-containing functional group, while the corresponding MeO ⋯ C(sp2) separations are relatively insensitive in accord with the different nucleophilicities of the two groups. These separations are a balance between a steric effect and a covalent interaction, and from a comparison of the Me2N ⋯ C and MeO ⋯ C distances for a given functional group it is proposed that the Me2N ⋯ C interaction has an attractive component if the Me2N ⋯ C separation is less than ∼(MeO ⋯ C + 0.15) Å, the latter factor arising from the greater size of the bonded nitrogen atom.