Electronic and geometrical structures of cyclopropanes, part 51. fluorocyclopropanes. linear correlation of orbital energies with C–C bond lengths. further improvement of the two-orbitals model

摘要

The electronic and geometrical structures of fluorocyclopropanes (1–12) have been analysed using DFT B3LYP calculations. A linear relationship, Δɛω=−0.172 Δr−0.171 (n=12, R=0.931), between Δɛω (in eV), the difference of the energies of the Walsh orbitals ωS and ωA, and Δr (in pm), the difference of vicinal and distal C–C bond lengths, is established. Correcting the orbital splitting by the basic value at Δr=0.00 pm, an even better linear correlation Δɛω eff=0.0720 Δr (n=12, R=0.984) is obtained. The results confirm the general applicability of the two-orbitals model for the relationship between geometrical and electronic structures for substituted cyclopropanes.