Interfacial assemblies of atypical amphiphilic porphyrins: hydrophobicity/hydrophilicity of substituents, annealing effects, and supramolecular chirality.

Interfacial molecular assemblies of eight atypical amphiphilic porphyrins, substituted with hydrophobic or hydrophilic substituents but without long alkyl chains on their molecular skeletons, have been investigated in terms of supramolecular chiralty generation and amplification. It is found that all of the originally organized interfacial molecular assemblies display very weak or undetectable supramolecular chirality. Interestingly, for those porphyrins bearing hydrophilic substituents, it is found that their molecular assemblies display distinct supramolecular chirality when applying a thermal annealing treatment. In contrast, for those bearing hydrophobic substituents, the formed assemblies remain achiral after similar treatment. This investigation suggests that the hydrophobicity/hydrophilicity of the substituents of the atypical amphiphilies could affect the occurrence of the interfacial mirror symmetry breaking substantially. It discloses that, although some of the interfacial assemblies are superficially achiral, a thermal annealing treatment could endow them with evident supramolecular chirality.