Reduction proton sponges

It was recognized that acenaphthene 40 and acenaphthylene 107 proton sponges, unlike the pair of compounds 11 and 124, easily interconvert by oxidation and reduction, respectively38. Since in the course of this transformation, the basicity change amounts to over four plsfa units (equation 11), these compounds form a redox system with easily modified basicity. It is believed that such properties may be of use in creating molecular devices38. 

There is little information on reduction of the aromatic system in proton sponges (Section III.J), whereas a lot of data exist concerning functional group reduction (Sections IV.A.5 and IV.C). 

Using D2 and NMR spectroscopy in the formation of lr(0) NPs from the reduction of [Ir(cod)(MeCN)2] in BM I.NTf2/acetone and proton sponge, Finke and coworkers have detected surface-ligand-coordinated N-heterocyclic carbenes. 

Figure 6.3 Stimuli-responsive polymers and their intracellular mechanisms leading to transfection. (A) Cationic polymers containing bioreducible disulfide bonds (S-S) can form tight complexes with DNA, releasing it in the cytosol, due to reduction of disulfide bonds to two thiol groups. (B) Associated polyplexes can he dissociated in the cytosol by temperature decrease, leading to DNA release. (C) The endosomal escape can be promoted by pH-responsive polymers such as PEI that act as proton sponges, preventing the normal acidification of the endosomes the continuous influx of protons, counterions and water eventually leads to endosomal disruption and DNA release.

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