Synthesis of Water-Soluble Triazinophanes and Evaluation of Their Molecular Recognition Properties

Molecular recognition properties of water-soluble tria-zinophane 1a-1c, derivatized through the straightforward SNAr reaction of common intermediate 5, were explored in aqueous media. Fluorescence titration of 1a-1c by using mono cationic aromatic hydrocarbon G1 and G2 as guests revealed that 1 prefers to form a host-guest complex with pyrene derivative G2 rather than anthracene derivative G1. Complex formation between the derivatives of 1 and G2 were in a 1: 1 equimolar ratio with binding constants of approximate to 8 x 10(3) ( M-1), regardless of the substitution groups on the triazine rings. In addition, we found that the molecular recognition of 1 was successfully fine-tuned through post-modification of the triazine rings. With dicationic anthracene G3 as a guest only 1b formed a host-guest complex ( K-a = 5.5 x 10(3) M-1).