Bile acid based receptors for multiple metal ion recognition

Quasi-Podands with 1,2,3-Triazole Rings from Bile Acid Derivatives: Synthesis, and Spectroscopic and Theoretical Studies

An innovative approach to producing derivatives of bile acids has been devised, utilizing the principles of "click" chemistry. By employing intermolecular [3 + 2] cycloaddition between the newly developed acyl propiolic esters of bile acids and the azide groups of 1,3,5-tris(azidomethyl)benzene, a novel class of quasi-podands featuring 1,2,3-triazole rings has been synthesized. Identifying and characterizing these six compounds involved comprehensive analysis through spectral techniques (1H NMR, 13C NMR, and FT-IR), mass spectrometry, and the PM5 semiempirical method. The synthesized compounds' pharmacotherapeutic potential has been evaluated, employing the Prediction of Activity Spectra for Substances (PASS) methodology. Additionally, molecular docking was performed for all molecules.

Self-assembled nanovesicles based on chiral bis-H8-BINOL for Fe3+ recognition and secondary recognition of l-cysteine by 1 + 1 complex

A novel fluorescent "off" sensor, R-β-d-1, was obtained in high yield (91.2%) by using octahydronaphthol as a backbone, introducing an alkyne group at the 2-position, and linking azido-glucose via a click reaction. The sensor was analyzed by scanning electron microscopy and transmission electron microscopy and was found to be a self-assembled vesicle. AFM results showed that the fluorescence burst was extinguished by the addition of Fe3+, and the fluorescence was restored by the addition of cysteine. This is due to charge transfer within the molecular structure, resulting in the ICT effect and phototransfer of electrons (PET), as well as redshifting (from 331 nm to 351 nm) and quenching of the fluorescence. The self-assembled vesicles of the fluorescent sensor R-β-d-1 encapsulated Fe3+, but upon addition of cysteine, the vesicles of R-β-d-1-Fe3+ were also complexed with it, forming the R-β-d-1-Fe3+-l-Cys complex, at which point fluorescence gradually returned. Therefore, the fluorescence test of this probe showed that the lowest detection limit of iron ions was 1.67 × 10-7 mol L-1, and its complexation mode was in the form of 1 + 1. The novel probe formed by R-β-d-1-Fe3+ can be used for the fluorescence detection of cysteine.

Bile acid-based receptors and their applications in recognition

Ion recognition has attracted great attention in the past decades because of its important role in biology, medicine, environment, and chemistry. The combination of rigidity, curved structure and amphiphilic nature makes bile acids a host system for ion recognition. In addition, the availability of hydroxyl groups in bile acids can be used for further derivatization to develop various ion recognition receptors. The detection of ions is revealed by the binding constant k_a value, log approach, and UV-visible or ¹H NMR titration, while visual detection is determined by gel-phase transition, colorimetric and fluorescent probes. In this review, we have discussed the bile acid-based receptors and their ion-recognition capability. These bile acid-based systems have the potential for the development of anion transport for biological activity.