The effect of halogen substitution on the bowl-to-bowl inversion, molecular structure and electronic properties of sumanene

Abstract

Halogen (X: F, Cl, and Br) substituted sumanene derivatives were subjected to a detailed computational study, exploring the molecular structure, bowl-depths, bowl-to-bowl inversion dynamics, and electronic properties. Hybrid density functional (DFT, B3LYP, X3LYP and PBEKCIS) theoretical calculations were performed with an array of basis sets 6-31+G(d,p) and cc-pVTZ. The bowl shaped geometry and other properties were significantly affected by the introduction of halogens (F, Cl, and Br). Especially, the bond length alternations (Delta(1) and Delta(2)) in the hub benzene ring and flank benzene ring of halogenated sumanenes (2Xa, 2Xb, and 12X) show remarkable sensitivity as a function of halogen with a wide range of fluctuations (0.011 to 0.071 angstrom). The introduction of fluorine to sumanene influences the bowl-to-bowl inversion energies slightly. The size of halogens seems to chiefly control the bowl depth and bowl-to-bowl inversion dynamic. In contrast, the bond length alternations seem to be controlled by electronic factors and not by the size of the substituted halogen atoms. The frontier molecular orbitals (FMOs) and molecular electrostatic potentials (MEPs) were significantly affected by the introduction of halogen atoms.