Porphyrin-Based Supramolecular Alternating Block Copolymer

S-shaped tetrakisporphyrin 1 forms supramolecular polymeric assemblies via a complementary affinity^1,2 of its bisporphyrin units in solution.³ The self-association constant determined by applying the isodesmic model is more than 10⁶ L mol^–1, which suggests that a sizable polymer forms at millimolar concentrations at room temperature. Trinitrofluorenone (TNF) binds within the molecular clefts provided by the bisporphyrin units via a charge transfer interaction. Thus, bisTNF guest can connect the tetrakisporphyrin via host-guest interaction to form an alternating block copolymer. In this presentation, we will discuss the structure transition from the tetrakisporphyrin-based supramolecular homopolymer to an alternating AB type block copolymer through competitive ditopic guest complexation.

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