In diamines with the basic centers in close proximity the spatial interaction of the nitrogen lone pairs can lead to unusual molecular properties. The exceptionally high basicity of the" proton sponge" 1, 8-bis (dimethylamino) naphtha-lene (1) results mainly from the destabilizing effect of the overlap of the nitrogen lone pairs and the steric strain in this diamine ['-31. Radical cations of diamines can also be significantly stabilized when the ...