| 20090170213 | High-Throughput Screening of Enantiomeric Excess (EE) - The present invention provides a method for high-throughput screening of enantiomeric excess (ee), comprising synthesizing a sensor made from an aggregate of gold nanoparticles whose surfaces have been elaborated with a chiral “host” that includes two optically pure binaphthol groups linked together by a diethanolamine bridge that is tethered via nitrogen to its associated gold nanoparticle, and in which aggregate the individual particles are held together by a bridging chiral “di-guest,” which contains an amino acid functionality at both ends and which interacts with the surface-bound hosts through hydrogen bonds. To screen, one adds a chiral analyte, which may be the product of an asymmetric catalytic reaction, or some other chiral species, in the form of a scalemic solution to a solution containing the aforemeritioned aggregate wherein one enantiomer of the analyte competes effectively with the “di-guest” for the “host,” while the other does not, and wherein a diastereoselective dispersion of the aggregate occurs, which brings about a large shift in the naked-eye-visible plasmon resonance absorption band of the gold nanoparticles, from a long wavelength for the aggregated nanoparticles to a shorter wavelength for the dispersed particles, and wherein the extent of the colour change is indicative of the degree to which the aggregate is dispersed and provides a rapid and effective measure of the ee of the chiral analyte. | 07-02-2009 |
