Open AccessThrough-Bond and Through-Space Interactions in [2,2]Cyclophanes
Author(s) -
Sérgio E. Galembeck,
Renato Pereira Orenha,
Rafael Martinez Madeira,
Letícia Bermudes Peixoto,
Renato L. T. Parreira
Publication year - 2021
Publication title -
journal of the brazilian chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.337
H-Index - 70
eISSN - 1678-4790
pISSN - 0103-5053
DOI - 10.21577/0103-5053.20210043
Subject(s) - chemistry , atomic orbital , atoms in molecules , pauli exclusion principle , covalent bond , non covalent interactions , electron density , ring (chemistry) , valence bond theory , computational chemistry , natural bond orbital , chemical physics , electron localization function , density functional theory , molecule , electron , physics , quantum mechanics , hydrogen bond , organic chemistry
The interpretation of the distortions of the electron distribution in [2,2]cyclophanes (22-CPs) is controversial. Some studies indicate that there is an accumulation of electron density (ρ) outside the cavity of 22-CPs. The nature of through-space (ts) interaction is still under debate. The relative importance of ts and through-bond (tb) is an open question. In an attempt to clarify these points, we have investigated five 22-CPs and their corresponding toluene dimers by molecular orbitals analysis, electron density difference analysis, some topological analysis of ρ (quantum theory of atoms in molecules (QTAIM), electron localization function (ELF) and noncovalent interactions (NCI)), and energy decomposition analysis with natural orbitals for chemical valence (EDA-NOCV). ρ is concentrated inside the inter-ring region. All the analyses indicated that ts is predominant. The ts is composed by attractive dispersion and Pauli repulsion, with a small covalent contribution. Except for 1 and 6, all the compounds present inter-ring bond paths.