pH-induced reversible molecular self-assembly of perylene based imidazolate ester: a probable marker for biological species

Abstract

Dianhydrides of perylene-3,4,9,10-tetracarboxylic acid (PTCDA) provide an excellent backbone for design and synthesis of various molecules of interest. Many water-soluble perylene derivatives with stimuli responded functionality being reported but there is few pH responded perylene derivatives were synthesized. The PTCDA derivatives so far synthesized are pH sensitive. These derivatives in an acid medium exist in its monomer form and undergo self-assembly with an increase in pH. In this paper, we report synthesis of pH-sensitive perylene based imidazolate ester, which exists in monomer form at pH 12 and undergo self-assembly with the decrease in pH contrary to the earlier reports. This phenomenon can be well explained for a probable marker in biological processes occurring specifically at pH 12.