Self-Aggregation, Enhanced Guest-Binding Behavior, and Anion-Induced Agglutination of Cyclophane Dimers Linked with Florescent Perylene Diimide.

Abstract

Cationic, anionic, and nonionic cyclophane dimers, 1a, 1b, and 1c, covalently linked with fluorescent perylene diimide were synthesized, respectively, as a host for aggregation-induced multivalent effects on guest-binding. These PDI-linked cyclophane dimers 1a and 1b, especially 1c, formed self-aggregates in H2O-rich solvents through π-stacking interactions. Critical aggregation concentrations of 1a, 1b, and 1c in H2O were 4.0 × 10-6, 4.0 × 10-6, and less than 0.1 × 10-6 M, respectively. The self-aggregates of the PDI-linked cyclophane dimers in H2O were several hundred nanometers in size by DLS and TEM measurements. In an aggregated state, 1a exhibited guest-binding abilities toward hydrophobic guests, such as 6-p-toluidinonaphthalene-2-sulfonate and 6-anilino-naphthalene-2-sulfonate. Moreover, anion-induced agglutination of 1a was observed upon the addition of phosphate ions, and its effectiveness was as follows: ATP > ADP > H2P2O72- > AMP ≈ PO43- > HPO42- > H2PO4-. The contribution of the adenine base of the nucleotides as a guest moiety used for effective agglutination was confirmed by 1H NMR spectroscopy.