Details

Autor(en) / Beteiligte

• Milanez, Bruno D.
• Santos, Gustavo M.
• Pinheiro, Max
• Ueno, Leonardo T.
• Ferrão, Luiz F. A.
• Aquino, Adelia J. A.
• Lischka, Hans
• Machado, Francisco B. C.

Titel

Structural stability and the low‐lying singlet and triplet states of BN‐n‐acenes, n = 1–7

Ist Teil von

• Journal of computational chemistry, 2023-03, Vol.44 (6), p.755-765

Ort / Verlag

Hoboken, USA: John Wiley & Sons, Inc

Erscheinungsjahr

2023

Quelle

Wiley Online Library

Beschreibungen/Notizen

• The chemical stability and the low‐lying singlet and triplet excited states of BN‐n‐acenes (n = 1–7) were studied using single reference and multireference methodologies. From the calculations, descriptors such as the singlet‐triplet splitting, the natural orbital (NO) occupations and aromaticity indexes are used to provide structural and energetic analysis. The boron and nitrogen atoms form an isoelectronic pair of two carbon atoms, which was used for the complete substitution of these units in the acene series. The structural analysis confirms the effects originated from the insertion of a uniform pattern of electronegativity difference within the molecular systems. The covalent bonds tend to be strongly polarized which does not happen in the case of a carbon‐only framework. This effect leads to a charge transfer between neighbor atoms resulting in a more strengthened structure, keeping the aromaticity roughly constant along the chain. The singlet‐triplet splitting also agrees with this stability trend, maintaining a consistent gap value for all molecules. The BN‐n‐acenes molecules possess a ground state with monoconfigurational character indicating their electronic stability. The low‐lying singlet excited states have charge transfer character, which proceeds from nitrogen to boron. The chemical stability of the ground state and the low‐lying singlet and triplet excited states of BN‐n‐acenes, (n = 1–7), were studied considering different methodologies and descriptors. Applying high‐level quantum chemical calculations, a direct comparison with the n‐acenes series is presented to derive a systematic picture of the properties of this interesting class of compounds.