A study on the influence of intramolecular OH⋯X (X = O and S) hydrogen bond formation on the aromaticity of heptafulvene derivatives, in which the methylene is replaced by , NH and O groups

The influence of the intramolecular OH⋯O and OH⋯S hydrogen bond on the aromaticity of some heptafulvene derivatives, in which the methylene group is replaced successively by AlH 2 - , BH 2 - , NH and O groups, is investigated using magnetic (NICS(0), NICS(1) and NICS(1)zz), geometrical (HOMA) and electronic (FLU and SA) criteria to consider the multidimensional character of aromaticity. It is found that the formation of intramolecular hydrogen bond changes aromatic character of heptafulvene derivatives. The variations of NICS indices due to the formation of intramolecular H-bonding significantly correlate with the properties of the considered hydrogen bonds, while the other indices do not give any meaningful results. It seems that the hydrogen bond influences the magnetic dimension of aromaticity in heptafulvenes. The influence of the OH⋯O and OH⋯S hydrogen bond on the aromaticity of these rings are also compared with each other.