| Autor: |
Trinquier G; Laboratoire de Chimie et Physique Quantiques, IRSAMC-CNRS-UMR 5626, Université Paul-Sabatier (Toulouse III), 31062 Toulouse, Cedex 4, France., Malrieu JP; Laboratoire de Chimie et Physique Quantiques, IRSAMC-CNRS-UMR 5626, Université Paul-Sabatier (Toulouse III), 31062 Toulouse, Cedex 4, France. |
| Jazyk: |
angličtina |
| Zdroj: |
The journal of physical chemistry. A [J Phys Chem A] 2024 Dec 17. Date of Electronic Publication: 2024 Dec 17. |
| DOI: |
10.1021/acs.jpca.4c06971 |
| Abstrakt: |
Recent work has documented conjugate polycyclic hydrocarbons presenting unusual properties: accepting full on-bond electron pairing, they could be considered as closed-shell architectures, but their ground-state wave function is actually a pure diradical singlet, free of any ionic component, in contrast to diradicaloids. These so-called entangled molecules also differ from disjoint diradicals, which do not accept on-bond electron pairing, in that their singly occupied molecular orbitals (SOMOs) are spatially entangled rather than disjoint. The present work first extends the study to a broad series of architectures exhibiting the same properties, namely: they present two degenerate SOMOs in the topological Hückel Hamiltonian, and their pure diradical wave functions lead to symmetry-keeping geometries. These solutions are always of lower energy than the closed-shell solutions that break symmetry and destroy aromaticity of some six-membered rings. A topological criterion ensuring that a given conjugate hydrocarbon will behave as an entangled pure diradical is then formulated. Next, a second set of molecules is proposed, still exhibiting two degenerate Hückel SOMOs, but with smaller contrast between the energies of open-shell and closed-shell solutions. Conservation of six-membered rings aromaticity appears as the driving factor ruling the stability of diradical solutions. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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