posted on 2002-06-04, 00:00authored byAlessandro Soncini, Remco W. A. Havenith, Patrick W. Fowler, Leonardus W. Jenneskens, Erich Steiner
Direct visualization of the π current density maps of highly strained annelated benzenes containing
cyclopropa, cyclobuta, and cyclobutadieno clamps, alone and in combination, using a reliable
distributed-origin, coupled Hartree−Fock method, shows the robustness of the classical benzene
diatropic π ring current. When only saturated clamps are used, the benzene ring current is
essentially unchanged. In contrast, annelation with one or more cyclobutadieno clamps disrupts
the benzene ring current. Analysis of orbital contributions to the current density maps gives a
unified account of these observations in terms of the nature of the HOMO−LUMO transition.