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Engineering Cyclodextrin Clicked Chiral Stationary Phase for High-Efficiency Enantiomer Separation.

Tang J, Zhang S, Lin Y, Zhou J, Pang L, Nie X, Zhou B, Tang W - Sci Rep (2015)

Bottom Line: Insights on the impact of CD functionalities in structure design are provided.High-efficiency enantioseparation of a range of aryl alcohols and flavanoids with resolution values (Rs) over 10 were demonstrated by per(3-chloro-4-methyl)phenylcarbamated CD clicked CSP.Comparison study and molecular simulations suggest the improved enantioselectivity was attributed to higher interactions energy difference between the complexes of enantiomers and CSPs with phenylcarbamated CD bearing 3-chloro and 4-methyl functionalities.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China [2] Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China.

ABSTRACT
The separation of racemic molecules is of crucial significance not only for fundamental research but also for technical application. Enantiomers remain challenging to be separated owing to their identical physical and chemical properties in achiral environments. Chromatographic techniques employing chiral stationary phases (CSPs) have been developed as powerful tools for the chiral analysis and preparation of pure enantiomers, most of which are of biological and pharmaceutical interests. Here we report our efforts in developing high-performance phenylcarbamated cyclodextrin (CD) clicked CSPs. Insights on the impact of CD functionalities in structure design are provided. High-efficiency enantioseparation of a range of aryl alcohols and flavanoids with resolution values (Rs) over 10 were demonstrated by per(3-chloro-4-methyl)phenylcarbamated CD clicked CSP. Comparison study and molecular simulations suggest the improved enantioselectivity was attributed to higher interactions energy difference between the complexes of enantiomers and CSPs with phenylcarbamated CD bearing 3-chloro and 4-methyl functionalities.

No MeSH data available.


Related in: MedlinePlus

(a) Solid state 13C NMR spectra of CCC3M4-CSP and CCM3C4-CSP, (b) the enantioseparation chromatograms of flavanone with increased concentrations at CCC3M4-CSP with 1.0 mL/min methanol as mobile phase. The inset showing the standard curve of quantitative analyses for flavanone.
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f3: (a) Solid state 13C NMR spectra of CCC3M4-CSP and CCM3C4-CSP, (b) the enantioseparation chromatograms of flavanone with increased concentrations at CCC3M4-CSP with 1.0 mL/min methanol as mobile phase. The inset showing the standard curve of quantitative analyses for flavanone.

Mentions: The successful click immobilization of CD was confirmed by solid state 13C NMR (Fig. 3a) and elemental analysis. Peaks between 140 and 110 ppm for the triazole groups indicate the reliable click of phenylcarbamate CD onto silica support. Signals between 140 and 110 confirm the successful functionalities of phenylcarbamate groups on CD. Signals in the region of 110-30 ppm are assigned to the carbon atoms in CD. The signals at 30-20 ppm are assigned to the C atoms of alkyl linkage between silica and triazole rings in CSPs. Peaks around 10 ppm are assigned to the C atoms of 4-methyl group in (3-chloro-4-methyl)phenylcarbamoyl groups. CCC3M4-CSP showed a content of 26.90% for carbon atom (C%), 1.546% for nitrogen atom (N%) and 4.317% for hydrogen atom (H%). And CCM3C4-CSP possessed 12.28% C, 0.822% N and 2.064% H. Both CSPs exhibited greatly increased contents of C, N, H atoms when compared with the corresponding C% (6.90%), N% (0.271%) and H% (1.526%) of alkynyl silica. The surface loading of CCC3M4-CSP and CCM3C4-CSP was calculated to be 0.37 and 0.18 μmol/m2 with [C%/(12 × NC × Ssilica)] × 106, where C% derived from elemental analysis of carbon, NC is the carbon atom number per CD molecule (here NC = 202) and Ssilica is the surface area of silica gel (300 g/cm2)12. The much lower suface loading of CCM3C4-CSP than CCC3M4-CSP is consistent with the solid NMR results. The as-packed columns with CCC3M4-CSP and CCM3C4-CSP delivered a column efficiency up to 13142 and 12794 plates/m, respectively, determined using toluene as test compound at 1.0 mL/min MeOH. These column efficiencies are much higher than the literature reported CCN-CSP and CCP-CSPs12202123.


Engineering Cyclodextrin Clicked Chiral Stationary Phase for High-Efficiency Enantiomer Separation.

Tang J, Zhang S, Lin Y, Zhou J, Pang L, Nie X, Zhou B, Tang W - Sci Rep (2015)

(a) Solid state 13C NMR spectra of CCC3M4-CSP and CCM3C4-CSP, (b) the enantioseparation chromatograms of flavanone with increased concentrations at CCC3M4-CSP with 1.0 mL/min methanol as mobile phase. The inset showing the standard curve of quantitative analyses for flavanone.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4530664&req=5

f3: (a) Solid state 13C NMR spectra of CCC3M4-CSP and CCM3C4-CSP, (b) the enantioseparation chromatograms of flavanone with increased concentrations at CCC3M4-CSP with 1.0 mL/min methanol as mobile phase. The inset showing the standard curve of quantitative analyses for flavanone.
Mentions: The successful click immobilization of CD was confirmed by solid state 13C NMR (Fig. 3a) and elemental analysis. Peaks between 140 and 110 ppm for the triazole groups indicate the reliable click of phenylcarbamate CD onto silica support. Signals between 140 and 110 confirm the successful functionalities of phenylcarbamate groups on CD. Signals in the region of 110-30 ppm are assigned to the carbon atoms in CD. The signals at 30-20 ppm are assigned to the C atoms of alkyl linkage between silica and triazole rings in CSPs. Peaks around 10 ppm are assigned to the C atoms of 4-methyl group in (3-chloro-4-methyl)phenylcarbamoyl groups. CCC3M4-CSP showed a content of 26.90% for carbon atom (C%), 1.546% for nitrogen atom (N%) and 4.317% for hydrogen atom (H%). And CCM3C4-CSP possessed 12.28% C, 0.822% N and 2.064% H. Both CSPs exhibited greatly increased contents of C, N, H atoms when compared with the corresponding C% (6.90%), N% (0.271%) and H% (1.526%) of alkynyl silica. The surface loading of CCC3M4-CSP and CCM3C4-CSP was calculated to be 0.37 and 0.18 μmol/m2 with [C%/(12 × NC × Ssilica)] × 106, where C% derived from elemental analysis of carbon, NC is the carbon atom number per CD molecule (here NC = 202) and Ssilica is the surface area of silica gel (300 g/cm2)12. The much lower suface loading of CCM3C4-CSP than CCC3M4-CSP is consistent with the solid NMR results. The as-packed columns with CCC3M4-CSP and CCM3C4-CSP delivered a column efficiency up to 13142 and 12794 plates/m, respectively, determined using toluene as test compound at 1.0 mL/min MeOH. These column efficiencies are much higher than the literature reported CCN-CSP and CCP-CSPs12202123.

Bottom Line: Insights on the impact of CD functionalities in structure design are provided.High-efficiency enantioseparation of a range of aryl alcohols and flavanoids with resolution values (Rs) over 10 were demonstrated by per(3-chloro-4-methyl)phenylcarbamated CD clicked CSP.Comparison study and molecular simulations suggest the improved enantioselectivity was attributed to higher interactions energy difference between the complexes of enantiomers and CSPs with phenylcarbamated CD bearing 3-chloro and 4-methyl functionalities.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China [2] Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China.

ABSTRACT
The separation of racemic molecules is of crucial significance not only for fundamental research but also for technical application. Enantiomers remain challenging to be separated owing to their identical physical and chemical properties in achiral environments. Chromatographic techniques employing chiral stationary phases (CSPs) have been developed as powerful tools for the chiral analysis and preparation of pure enantiomers, most of which are of biological and pharmaceutical interests. Here we report our efforts in developing high-performance phenylcarbamated cyclodextrin (CD) clicked CSPs. Insights on the impact of CD functionalities in structure design are provided. High-efficiency enantioseparation of a range of aryl alcohols and flavanoids with resolution values (Rs) over 10 were demonstrated by per(3-chloro-4-methyl)phenylcarbamated CD clicked CSP. Comparison study and molecular simulations suggest the improved enantioselectivity was attributed to higher interactions energy difference between the complexes of enantiomers and CSPs with phenylcarbamated CD bearing 3-chloro and 4-methyl functionalities.

No MeSH data available.


Related in: MedlinePlus