A computational study of the arsabenzenes: Structure, properties and aromaticity

The electronic structure and properties of the arsabenzenes series have been investigated using hybrid density functional B3LYP theory. Basic measures of aromatic character derived from structure, molecular orbital and chemical shift. Energetic criteria suggest that 1,2,3-triarsabenzene and, to a less extent, 1,2-diarsabenzene and its complement 1,2,3,4-tetraarsabenzene enjoy conspicuous stabilization. However, by magnetic criteria, these systems are among the least aromatic of the family: population and bond order analyses reveal that they derive part of their stability from ionic contributions to the bonding. Within their isomer series, 1,3-diarsaabenzene,1,3,5-triarsabenzene, and 1,2,3,5-tetraarsabenzene are the most aromatic using magnetic criteria: overall magnetic aromaticity decreases with increasing number of As atoms.