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A combination of Schwesinger's phosphazene base concept and the idea of the disubstitued 1,8-naphthalene spacer, yields a superbase, 1,8-bis(hexamethyltriaminophosphazenyl)naphhalene (HMPN), which is the most basic representative of 'proton sponges'. The high basicity of HMPN is a consequence of the high energy content of the base in its initial neutral state and the intramolecular hydrogen bonding in the resulting conjugate acid with contributions to proton affinity.

Results reveal that polyguanidines exhibit very high proton affinities with the linear chain poly-guanides saturation effect depending on the number of guanidine units. A doubly bifurcated heptaguanide shows the largest proton affinity caused by substantial resonance effect of the protonation.

The characterization of dimethylethyleneguanidino (DMEGN) reveals an unsymmetrical intramolecular hydrogen bridge. It is stated that, a new proton sponge provides a new crossbar in the ladder of highly basic neutral organic compounds.