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The Halogen Bond in Weakly Bonded Complexes and the Consequences for Aromaticity and Spin-Orbit Coupling
- Source :
- Molecules, 28(2):772. MDPI AG, Molecules: a journal of synthetic chemistry and natural product chemistry, Molecules; Volume 28; Issue 2; Pages: 772
- Publication Year :
- 2023
-
Abstract
- The halogen bond complexes CF (Formula presented.) X⋯Y and C (Formula presented.) F (Formula presented.) X⋯Y, with Y = furan, thiophene, selenophene and X = Cl, Br, I, have been studied by using DFT and CCSD(T) in order to understand which factors govern the interaction between the halogen atom X and the aromatic ring. We found that PBE0-dDsC/QZ4P gives an adequate description of the interaction energies in these complexes, compared to CCSD(T) and experimental results. The interaction between the halogen atom X and the (Formula presented.) -bonds in perpendicular orientation is stronger than the interaction with the in-plane lone pairs of the heteroatom of the aromatic cycle. The strength of the interaction follows the trend Cl < Br < I; the chalcogenide in the aromatic ring nor the hybridization of the C–X bond play a decisive role. The energy decomposition analysis shows that the interaction energy is dominated by all three contributions, viz., the electrostatic, orbital, and dispersion interactions: not one factor dominates the interaction energy. The aromaticity of the ring is undisturbed upon halogen bond formation: the (Formula presented.) -ring current remains equally strong and diatropic in the complex as it is for the free aromatic ring. However, the spin-orbit coupling between the singlet and triplet (Formula presented.) states is increased upon halogen bond formation and a faster intersystem crossing between these states is therefore expected.
Details
- Language :
- English
- ISSN :
- 14315157 and 14203049
- Database :
- OpenAIRE
- Journal :
- Molecules, 28(2):772. MDPI AG, Molecules: a journal of synthetic chemistry and natural product chemistry, Molecules; Volume 28; Issue 2; Pages: 772
- Accession number :
- edsair.doi.dedup.....d22f01796ff5fde8b1f9c71f8ab6872f