Macrocyclic Bisbinaphthyl Fluorophores and Their Acyclic Analogues:  Signal Amplification and Chiral Recognition

• Published in: Journal of organic chemistry 2004-09, Vol.69 (19), p.6284-6293
• Main Authors: Li, Zi-Bo, Lin, Jing, Zhang, Hui-Chang, Sabat, Michal, Hyacinth, Marilise, Pu, Lin
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; Fluorescent Dyes - chemistry; Heterocyclic compounds; Heterocyclic compounds with several n hetero atoms in the same ring, in separated rings or in fused rings; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure; Organic chemistry; Preparations and properties; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Stereoisomerism
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo049366a

A series of optically active macrocyclic and acyclic bisbinaphthyls have been synthesized and characterized. The structure of one of the bisbinaphthyl macrocycles has been established by a single-crystal X-ray analysis. The UV and fluorescence spectra of these chiral compounds in various solvents and at different concentrations are studied. Formation of excimers is observed for the macrocyclic bisbinaphthyl compounds. Introduction of conjugated substituents to the 6,6‘-positions of the binaphthyl units in the macrocycles leads to greatly amplified fluorescence signals. Using the 6,6‘-substituted bisbinaphthyl macrocycles in place of the unsubstituted macrocycles allows a 2 orders of magnitude reduction in the sensor concentration for the fluorescence measurements. These macrocycles have exhibited highly enantioselective fluorescent enhancements in the presence of chiral α-hydroxycarboxylic acids and N-protected α-amino acids. They are useful as fluorescent sensors for chiral recognition. The macrocycles show much greater enantioselectivity in the substrate recognition than their acyclic analogues.