Direct visualisation of induced current density in clamped benzenes 1-4 dis
tinguishes between saturated clamping groups, for which the central benzene
ring retains a conventional diamagnetic ring current, and strongly interac
ting, unsaturated clamps, for which the central ring supports only the loca
lised circulations expected of a 1,3,5-cyclohexatriene with fully fixed dou
ble bonds.