Abstract
R- and S-propylene oxide (PO) have been shown to interact enantiospecifically with the chiral surfaces of Au nanoparticles (NPs) modified with D- or L-cysteine (cys). This enantiospecific interaction has been detected using optical polarimetry measurements made on solutions of the D- or L-cys modified Au (cys/Au) NPs during addition of racemic PO. The selective adsorption of one enantiomer of the PO onto the cys/Au NP surfaces results in a net rotation of light during addition of the racemic PO to the solution. In order to optimize the conditions used for making these measurements and to quantify enantiospecific adsorption onto chiral NPs, this work has measured the effect of temperature, wavelength and Au NP size on optical rotation by solutions containing D- or L-cys/Au NPs and racemic PO. Increasing temperature, decreasing wavelength and decreasing NP size result in larger optical rotations.
Highlights
The importance of chirality arises from the need of the pharmaceutical industry, and other producers of bioactive compounds, for chemical processes that are enantioselec‐ tive and thereby produce enantiomerically pure chiral products. [1,2,3,4] This is one of the most challenging forms of chemical synthesis and is critical to the performance of bioactive chiral products
In order to optimize the conditions used for making these measurements and to quantify enantiospecific adsorption onto chiral nanopar‐ ticles (NPs), this work has measured the effect of temperature, wavelength and Au NP size on optical rotation by solutions containing D- or L-cys modified Au (cys/Au) NPs and racemic propylene oxide (PO)
Following the procedures developed and described in our previous studies of optical rotation by solutions of PO and chiral cys/Au NPs, [32], [33] this study has measured the optical rotation of solutions prepared by adding racemic propylene oxide (rac-PO) in increasing concentrations to solutions containing D- or Lcys/Au NPs
Summary
The importance of chirality arises from the need of the pharmaceutical industry, and other producers of bioactive compounds, for chemical processes that are enantioselec‐ tive and thereby produce enantiomerically pure chiral products. [1,2,3,4] This is one of the most challenging forms of chemical synthesis and is critical to the performance of bioactive chiral products. The simplest form of chirality induction into a metal NP occurs by adsorption of a chiral ligand onto the NP surface. ≠ KS ⁄D = KR⁄L , where KR/D is the adsorption equilibrium constant for R-PO on D-cys/Au NPs. As a result, the concentrations of the two enantiomers of PO in solution differ, and their concentrations in the adsorbed phase differ. The use of optical rotation measurements as a means of quantifying enantiospecific adsorption constants relies on careful measurements of optical rotation in solutions with many different concentrations of chiral probe molecules and chiral NPs. Optical rotation will depend on the wavelength of the light being used for the measurements and on the concentrations of probe molecule enantiomers in the solution phase and adsorbed phase. The influence of wavelength, temperature and NP size on optical rotation is complex, and so the empirical study described has been performed to explore their influence on optical rotation in order to guide future work towards choosing experimental parameters that will maximize measurement sensitivity and thereby optimize the quality of the resulting data
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
