A novel stationary phase for chiral chromatography: poly-L-leucine supported on porous graphitic carbon and its application to the separation of the enantiomers of chiral epoxides

Kelly, Elizabeth J.; Haddleton, David M.; Crout, David H. G.; Ross, Paul; Dutton, James

doi:10.1039/a901367i

Cited by 10 publications

(5 citation statements)

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“…16 Chiral chromatography is an especially valuable technique because it allows simultaneous detection and collection of both enantiomers, a feature that has important implications for the detection of enantiomeric impurities and the measurement of enantiomeric excess. One surface that has received recent attention in chiral chromatography is porous graphitic carbon, which has been chirally modified to effect the separation of enantiomers of chiral epoxides 17 and amino acids. 18 Here we describe another form of graphite surface that can be modified by the adsorption of achiral molecules, which themselves adopt a pseudo 2D chirality when adsorbed onto the graphite substrate.…”

Section: Introductionmentioning

confidence: 99%

Odd/Even Effect in Self-Assembly of Chiral Molecules at the Liquid−Solid Interface: An STM Investigation of Coadsorbate Control of Self-Assembly

2002

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Manipulation of the self-assembly of chiral 2-bromohexadecanoic acid by templates composed of coadsorbed achiral molecules has been investigated at the liquid-solid interface using scanning tunneling microscopy (STM). The template formed by the odd-numbered saturated fatty acid heptadecanoic acid induces coadsorption of R-2-bromo-hexadecanoic acid and S-2-bromo-hexadecanoic acid within a single domain. Specifically, heptadecanoic acid effects an intra-lamellar alternation of R and S-2-bromo-hexadecanoic acid molecules, which is further confirmed by studies of heptadecanoic acid with pure R-2-bromo-hexadecanoic acid. Templates formed by even-numbered acids such as hexadecanoic acid induce the segregation of R-and S-2-bromohexadecanoic acid into separate (R or S) domains.

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Section: Introductionmentioning

confidence: 99%

Odd/Even Effect in Self-Assembly of Chiral Molecules at the Liquid−Solid Interface: An STM Investigation of Coadsorbate Control of Self-Assembly

2002

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“…Its microscopic surface structure, coupled with a strong π-electron character, facilitates the separation of a wide variety of analytes . The hydrophobic character of PGC has also been exploited as a basis for creating chiral stationary phases by the dynamic adsorption of different types of enantiomers. − …”

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confidence: 99%

Chemical Modification of Carbonaceous Stationary Phases by the Reduction of Diazonium Salts

et al. 2001

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This paper describes a new strategy for the creation of chemically modified carbonaceous stationary phases. The strategy exploits the electroreduction of arenediazonium salts as a means for functionalizing the surface of glassy carbon (GC) and porous graphitic carbon (PGC) stationary phases. The one-electron reduction of these salts forms an arene radical which then couples via a carbon-carbon linkage to the carbon framework at the surface of the stationary phase. Two arenediazonium-based modifiers were used in evaluating the potential utility of this strategy: 4-nitrobenzenediazonium tetrafluoroborate for the GC and PGC phases and 4-hexylbenzenediazonium tetrafluoroborate for only the PGC phases. Modifications were carried out by packing the phases into a column used for electrochemically modulated liquid chromatography. The effectiveness of the modifications was assessed by X-ray photoelectron spectroscopy and by comparing the liquid separation of a series of mixtures before and after coating deposition. For the nitrobenzyl-modified GC phase, the test mixture contained both anisole and fluoranthene. The performance of the nitrobenzyl- and hexylbenzyl-modified PGC stationary phases was characterized by the separations of substituted phenols (i.e., nitrophenol and resorcinol) and a few important pharmaceutical agents (i.e., hexobarbital, oxazepam, and nitrazepam). The potential utility of this modification procedure to form stationary phases that are stable upon extended exposure to aggressive mobile phases is discussed and briefly examined.

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“…It is therefore not surprising that a supported version of this polymer (on porous graphitic carbon) is an efficient stationary phase for the separation of these chiral epoxides. 49 An improved protocol for the Juliá-Colonna epoxidation uses sodium percarbonate as terminal oxidant, allowing increased substrate : catalyst ratios without loss of selectivity. 50 In other related work, Carde et al have applied this methodology to the synthesis of arylpropionic acids, making use of polyleucine absorbed onto silica.…”

Section: Three-membered Ringsmentioning

confidence: 99%

Saturated oxygen heterocycles

Elliott

Williams

2001

J. Chem. Soc., Perkin Trans. 1

123

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A novel stationary phase for chiral chromatography: poly-L-leucine supported on porous graphitic carbon and its application to the separation of the enantiomers of chiral epoxides

Abstract: A novel chiral stationary phase consisting of poly-l-leucine supported on porous graphitic carbon has been shown to be effective in the separation of the enantiomers of epoxides 1-5 by chiral high performance liquid chromatography.

Cited by 10 publications

References 9 publications

Odd/Even Effect in Self-Assembly of Chiral Molecules at the Liquid−Solid Interface: An STM Investigation of Coadsorbate Control of Self-Assembly

Odd/Even Effect in Self-Assembly of Chiral Molecules at the Liquid−Solid Interface: An STM Investigation of Coadsorbate Control of Self-Assembly

Chemical Modification of Carbonaceous Stationary Phases by the Reduction of Diazonium Salts

Saturated oxygen heterocycles

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