Design of steroid-based imidazolium receptors for fluoride ion recognition

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.

Cholesteric Chiral Molecular Tweezer for Rapid Detection of F- in Food Samples

Chiral cholesteric molecular tweezer 7d was synthesized and its influences on changes in the ultraviolet (UV) and fluorescence spectra of various anions were investigated. The results displayed that molecular tweezer 7d selectively recognized F⁻ ions in dimethyl sulfoxide with a detection limit of 5.14 μmol/L, while other anions had little interference. On this basis, a method for the rapid detection of F⁻ ions by host molecular tweezer 7d was established, and the naked-eye detection of F⁻ was realized through the unique yellow color of the complex solution. According to the determination of F⁻ ions in real food samples, it was proved that the established method had good application prospects in F⁻ ion detection.

Dehydroepiandrosterone derived imidazolium salts and their antimicrobial efficacy

Hybrid molecules consisting of steroid-imidazolium salts reveal interesting biological properties, especially regarding antimicrobial activities. Novel dehydroepiandrosterone derived imidazolium salts (11 salts) with side chains of different lengths were obtained in an efficient and straightforward synthetic route. Antimicrobial properties of new salts were examined by determining their minimum inhibitory concentrations (MICs). They were studied against several strains of bacteria, including clinical isolates of MRSA, and fungi. New compounds showed high activity against Gram-positive bacteria and Candida albicans as well as good compatibility with the representatives of the host cells when applied at concentrations corresponding to MIC value. The studies indicated high antimicrobial efficacy of imidazolium salts against the above-mentioned microorganisms with low hemolytic activity at a concentration that restricts the growth of the microorganisms. The interference of salts with the immune defense system, the influence on the biological activity of monocytes/macrophages measured by their viability and metabolic activity was also studied. The new compounds have shown immunoprotective properties.

Synthesis and antimicrobial properties of steroid-based imidazolium salts

Imidazolium salts reveal interesting biological properties, especially regarding antitumor and antimicrobial activities. Two series of imidazolium salts based on steroids were obtained in an efficient and convenient synthesis. They were biologically tested to evaluate their antibacterial and antifungal properties. The activities of new salts, especially in relation to Gram-positive bacterial strains are comparable to the activities of known antibiotics. The most promising activity was that against C. albicans, which exceeded the antifungal activity of commonly used drugs. Some of the new salts exhibited improved antifungal activities against phytopathogenic fungi: B. cinerea and C. beticola. Our research showed that new compounds could be potentially useful as antifungal antibiotics or inhibiting agents against pathogenic fungi.

A novel dansyl-appended bile acid receptor for preferential recognition of Hg2+

A novel dansyl appended bile acid receptor has been synthesized using click chemistry which shows high selectivity for Hg²⁺ ions.

Synthesis of Novel Chiral Cholic Acid-Based Molecular Tweezers Containing Unsymmetrically Disubstituted Urea Units Using Microwave Irradiation

An efficient procedure has been developed for the synthesis of new chiral cholic acid molecular tweezer artificial receptors by linking an unsymmetrically disubstituted urea to methyl deoxycholate via a carbonate chain using microwave irradiation. The structures of these new receptors were confirmed by 1H NMR, IR, MS spectra and elemental analysis. Their binding properties were examined by UV-Vis spectra titration. The preliminary results indicate that these molecular tweezers not only recognised anions, but also showed good enantioselectivity for D-amino acid methyl esters.

One-pot Synthesis of New Carbamate-Type Molecular Tweezers Derived from Deoxycholic Acid under Microwave Irradiation

A rapid, safe, and efficient method for the preparation of new carbamate type molecular tweezers based on deoxycholic acid was reported. Eleven new molecular tweezers have been synthesised in good yield(91–96%). The structures of these receptors were confirmed by 1H NMR, IR, MS spectra and elemental analysis. These molecular tweezers not only recognised neutral molecules, but also showed good enantioselectivity for D-amino acid methyl esters.

Synthesis of Novel Alkoxycarbonyl Thiosemicarbazide Molecular Tweezers derived from Deoxycholic Acid under Microwave Irradiation

A series of novel 12α-alkoxycarbonyl thiosemicarbazide molecular tweezers based on 3α-(1-naphthoyl) deoxycholic acid methyl ester were synthesised under microwave irradiation. Their structures were characterised by 1H NMR, IR, MS spectra and elemental analysis. Their chiral recognition properties for the methyl esters of amino acids were investigated. The preliminary results showed that these molecular tweezers have good enantioselective recognition for D/L-amino acid methyl esters.

Revisit to imidazolium receptors for the recognition of anions: highlighted research during 2006-2009

In this tutorial review we discuss imidazolium receptors for anion recognition and recent contributions between 2006-2009 are reviewed according to target analytes, such as ATP and DNA, as well as structural classification, including cage type imidazoliums, imidazolium calixarenes, ferrocenyl imidazoliums, chiral systems, fluorescent or colorimetric imidazoliums, imidazolium cyclophane, nano assembled structures, bile acid-imidazolium, and tripodal-imidazolium systems.