Chiral artificial sensors

An emerging area of modem enantioselective analytics is the development of dedicated, target-specific molecular tools that meet the criteria of being robust, high throughput, and specific [105]. Important groups of such tools constitute chiral artificial sensors and receptors as well as polymer-based chiral materials, such as... 

The area covered is very widespread and the role of the calixarene molecules reach from a simple platform or skeleton on which to assemble chiral centers to an inherent part of the chiral structure. Biologically active molecules or derivatives are involved as well as artificial ligands and their metal complexes. Chiral calixarenes have been used as stationary phases in analytical separations or as host molecules in sensors. Basic properties of calixarenes, such as their conformational stabilities, have been studied with chiral derivatives as well as more... 

In the area of cyclodextrin ethers the -compound has been converted into a set of five tris-Tbdms ethers, all substituted at their various 6-positions, which were separated by hplc and characterized by n.m.r. spectroscopy. Related work applied to y-cyclodextrin gave the various 6,6 -disubstituted ethers. 5-Bromo-l-pentene was used to produce the 2-0-mono-4-pentenyl ether of P-cyclodextrin which was then permethylated and the product was chemically bonded to silica gel to form an efficient hplc stationary phrase for the separation of enantiomers. Peroctyl a-cyclodextrin has been studied as a chiral receptor for the ephedrinium ion. Various octyl ethers of a-, P- and y-cyclodextrin ranging in their substitution from the diethers to completely alkylated products were characterized by electrospray mass spectrometry and n.m.r. methods applied to methylated derivatives. The 2,6-didodecyl derivative of p-cyclodextrin has been used as a potentiometric sensor. In the field of aromatic ethers, naphthyl carboxylate substituents have been bonded at the 6-positions and the products were able to transfer excitation energy to complexed merocyanine held in the cavities of those molecules. These phototransfer processes were extremely efficient.P-Substituted cyclodextrin derivatives with p-allyloxybenzoyl or various benzyl substituents at 0-2 or 0-3 were incorporated by hydrosilylation to give hydromethylpolysiloxane polymers used as chiral phases for chromatographic resolution of enantiomers. Cyclodextrins with complex benzyl-like eth are illustrated in 22 and 23. The latter were prepared as artificial redox enzymes. 

---