Through-space stabilizing electronic effect

In 30 % aqueous alcoholic methanol, electron-withdrawing substituents reduce the ease of oxidation of tertiary alkylamines by [FeCCN) ] -. The closer the substituent to the reaction centre, the more effective is the retardation. Cyclic amines show evidence for through-space stabilization of the incipient aminium radical with an accompanying increase in rate. 

Investigation of environmental effects. As has been stressed in this chapter, homoaromaticity is just a matter of a few kcal mol-1 stabilization energy in most cases, and therefore environmental effects may have a large impact on structure, stability and other properties of a homoaromatic compound. Future work in theory (as well as in experiment) has to clarify how environmental effects can influence electron delocalization, through-space interactions and bonding in homoaromatic molecules. The theoretical methods are now available to calculate solvent and counter ion effects (for homoaromatic ions in solution) or to study intermolecular and crystal packing forces in the solid state. 

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