Three dimensional aromaticity in pyramidanes C4R4E and Ge4R4Ge

Three dimensional aromaticity in pyramidanes C4(SiMe3)4E (E = Ge, Sn, Pb, P+, BCl, Mg) and Ge4(SiMe3)4Ge was investigated using gauge-included magnetically induced currents and electron density of delocalized bonds as two criteria. For the C4(SiMe3)4E compounds, different series of the aromaticity degree have been obtained by the two methods, respectively: P > Ge ≥ Sn ∼ Pb > B and Pb ≥ Sn ≥ Ge > B > P. Two isomers of Ge4(SiMe3)4Ge possess nearly equal aromaticity.