Exploring aromatic character of three-dimensional hydrogen cluster with the B3LYP hybrid density functional theory method

Density functional theory studies were performed on linear and three-dimens ional (3D) highly symmetric hydrogen clusters with the target being to dete rmine the existence of 3D aromaticity and the rules that are applied in con junction with the number of sigma-electrons to their stability. The relativ e energies of these 3D clusters were compared with the relative energies of linear clusters. It was demonstrated that the relative stability of 3D clu sters alters with the changing number of sigma-electrons, similar to planar cyclic polyenes. Therefore, it was concluded that the 3D aromaticity is pr esent in these chemical systems. Aromatic rules that are applied for single t planar molecular systems are applicable for triplet 3D systems and vice v ersa. (C) 2000 Elsevier Science B.V. All rights reserved.