Hyperconjugation, an interaction of electrons in a σ orbital or lone pair with an adjacent π or even σ antibonding orbital, can have a strong effect on aromaticity. However, most work on hyperconjugative aromaticity has been limited to main-group substituents. Here, we report a thorough density functional theory study to evaluate the aromaticity in various cyclopentadienes that contain both main-group and transition-metal substituents.

In this paper, the trans influence of boryl ligands, together with that of other ligands commonly believed to have a strong trans influence, has been investigated theoretically via density functional theory (DFT) calculations on a series of square-planar platinum(II) complexes of the form trans-[PtL(Cl) (PMe3)(2)].