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

Molecular recognition properties of water‐soluble triazinophane 1a – 1c , derivatized through the straightforward S N Ar 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 ≈ 8 × 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 × 10 3 m –1 ).