Planar Octacoordinate Aluminium in Dual Aromatic AlBe4N4− Cluster

• Published in: Journal of cluster science 2023-03, Vol.34 (2), p.1133-1139
• Main Authors: Kalita, Amlan J., Rohman, Shahnaz S., Kashyap, Chayanika, Ullah, Sabnam S., Baruah, Indrani, Mazumder, Lakhya J., Konwar, Dimpul, Guha, Ankur K.
• Format: Article
• Language: English
• Subjects: Aluminum; Aromaticity; Catalysis; Chemistry; Chemistry and Materials Science; Clusters; Covalent bonds; Density functional theory; Electrons; Energy; Entropy; Inorganic Chemistry; Localization; Nanochemistry; Original Paper; Physical Chemistry; Planar structures; Quantum chemistry; Tetrahydrofuran; Vapor phases
• ISSN: 1040-7278; 1572-8862
• DOI: 10.1007/s10876-022-02295-6

High level quantum chemical methods based on density functional theory and coupled cluster have been carried out to predict AlBe 4 N 4 − cluster containing a planar octacoordinate aluminium centre. The neutral cluster has a quasi-planar structure in which the central Al atom lies only 0.30 Å above the molecular plane. The global minimum of the anionic cluster is perfectly planar and features dual aromaticity (orthogonally delocalized (4n + 2; n = 1) σ and π orbitals in the Hückel framework) and it is thermodynamically very stable. The dual aromatic behaviour of this cluster comes from the planarity of the ring, delocalized (4n + 2) σ and π bonds which has been supported by Shannon aromaticity index and σ,π—separated electron localization function analyses. The anionic cluster has been found to have profound Lewis acidity. The calculated gas phase fluoride ion affinity and its reaction with tetrahydrofuran reveal that the proposed cluster has profound Lewis acidic character. Graphical Abstract Theoretical search for the planar octacoordinate aluminium centre has been made. The global isomer features dual aromaticity and is thermodynamically very stable. The proposed cluster features profound reactivity.