Crown ether capped cyclodextrin used as stationary phase for capillary gas chromatography

Zeng, Zhaorui; Liu, M.

doi:10.1007/bf02467654

Cited by 9 publications

(7 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After collection by filtration, the crude product was purified by column chromatography on Sephadex G-25 with distilled, deionized water as eluent to give a pure sample (0.50 g, yield 18%). Mp 240 °C (dec.); 1 H NMR (D 2 O, 300 MHz, TMS, ppm):  2.0-3.0 (m, 11H), 3.0-4.0 (m, 58 H), 4.1 (m, 2H), 4.9 (m, 7 H), 6…”

Section: Synthesis Of N-(benzoaza-15-crown-5)-acylaminomethylene Teth...mentioning

confidence: 99%

“…1 Recently, many approaches to appropriately introduce another recognition site, such as a CyD, calixarene or crown ether, to the parent CyD rim have been widely reported. [2][3][4][5][6][7][8] For example, it was reported that crown ether capped -CyDs can mimic the receptor sites of enzymes, 5c and thus successfully be used as artificial enzyme-mimetic systems to accelerate the hydrolysis of p-nitrophenyl ester in the presence of transition metal cations 9 or as stationary-phase selector for chromatography showing excellent enantioselectivity. 10 Moreover, Suzuki et al reported the strong binding of tryptophan by crown ether-tethered CyDs owing to the superiority of the CyD secondary-hydroxyl side modification.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cooperative self-assembly and molecular binding behavior of cyclodextrin–crown ether conjugates mediated by alkali metal ions

et al. 2004

View full text Add to dashboard Cite

In order to quantitatively investigate their molecular binding ability, a series of cyclodextrin-crown ether conjugates containing beta-cyclodextrin (beta-CyD) and crown ether units, i.e.N-(benzoaza-15-crown-5)acylaminomethylene tethered 6-diethylenetriamino-6-deoxy-beta-CyD, N-(benzoaza-15-crown-5)acylaminomethylene tethered 6-triethylenetetraamino-6-deoxy-beta-CyD and 4',5'-dimethylene-benzo-15-crown-5 tethered 6-diethylenetriamino-6-deoxy-beta-CyD, have been prepared as ditopic molecular receptors. Their inclusion complexation behavior with four representative fluorescent dyes, i.e. ammonium 8-anilino-1-naphthalenesulfonate (ANS), sodium 6-toluidino-2-naphthalenesulfonate (TNS), acridine red (AR) and rhodamine B (RhB), has been comprehensively investigated in aqueous NaH2PO4/Na2HPO4 or KH2PO4/K2HPO4 buffer solution (pH 7.20) by means of circular dichroism, fluorescence, and 2D NMR spectra. The results indicate that the self-assembly of crown ether modified beta-CyD mediated by potassium ion exhibits a dimeric structure, which significantly enhances the original binding ability and molecular selectivity of parent beta-CyD and its derivatives towards guest molecules through the cooperative binding of two hydrophobic CyD cavities with one guest. This cooperative binding mode of K+/CyD-crown ether systems are further confirmed by Job's experiments and 2D NMR investigations. Attributed to the positive contributions from the metal-ligated crown ether cap and K+-mediated dimerization of CyDs, the binding constant (Ks) values of CyD-crown ether conjugates toward ANS are 10-83 times higher than that of beta-CyD. The increased binding ability and molecular selectivity of CyD-crown ether conjugates are discussed from the viewpoints of size/shape-fit and multiple recognition mechanism.

show abstract

Section: Synthesis Of N-(benzoaza-15-crown-5)-acylaminomethylene Teth...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cooperative self-assembly and molecular binding behavior of cyclodextrin–crown ether conjugates mediated by alkali metal ions

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Another option is to examine a more orthogonal chromatographic approach [16,17] which may include chiral chromatography either in reversed or normal-phase mode and using either a chiral mobile phase additive (CMPA) [18] or a CSP [19][20][21][22][23]. Furthermore, an orthogonal analytical technique may also be utilized and positional isomer separations have been reported using capillary electrophoresis (CE) [19,24], capillary electrochromatography [25], supercritical fluid chromatography [26] and gas chromatography [27]. Capillary electrophoresis, where the separation mechanism is truly orthogonal to that of reversedphase chromatography, can also be very effective in separating isomers, both optical or positional, when a chiral medium is employed in the background electrolyte.…”

Section: Introductionmentioning

confidence: 99%

Determination of the enantiomer and positional isomer impurities in atomoxetine hydrochloride with liquid chromatography using polysaccharide chiral stationary phases

Sellers

Olsen

Owens

et al. 2006

Journal of Pharmaceutical and Biomedical Analysis

View full text Add to dashboard Cite

“…It was reported that crown ether-capped b-CDs [15 ± 17] exhibited high binding constants for several guest molecules due to the cooperation of the b-CD and the crown ether. Although crown ether capped b-CD has already been used to model the receptor sites of enzymes for a long time [16], its use as a stationary-phase selector for chromatography has seldom been studied [18]. It was reported that benzo-aza-15-crown-5 capped b-CD used as stationary phase in GC showed excellent enantioselectivity [18].…”

mentioning

confidence: 99%

“…Although crown ether capped b-CD has already been used to model the receptor sites of enzymes for a long time [16], its use as a stationary-phase selector for chromatography has seldom been studied [18]. It was reported that benzo-aza-15-crown-5 capped b-CD used as stationary phase in GC showed excellent enantioselectivity [18]. Recently, it was shown that combination of a crown ether and b-CD as CE additive sometimes produce better enantiomer separation than did either selector alone [9] [19] [20].…”

mentioning

confidence: 99%

Enantiomeric Separations in Capillary Electrochromatography with Crown Ether-Capped -Cyclodextrin-Bonded Silica Particles as Chiral Stationary Phase

Gong

Lee

2002

HCA

View full text Add to dashboard Cite

Dedicated to Professor Dieter Seebach on the occasion of his 65th birthday Two novel types of crown ether capped b-cyclodextrin (b-CD) bonded silica, namely, 4'-aminobenzo-Xcrown-Y (X 15, 18 and Y 5, 6, resp.) capped [3-(2-O-b-cyclodextrin)-2-hydroxypropoxy] propylsilylappended silica, have been prepared and used as stationary phases in capillary electrochromatography (CEC) to separate chiral compounds. The two stationary phases have a chiral selector with two recognition sites: crown ether and b-CD. They exhibit excellent enantioselectivity in CEC for a wide range of compounds. After inclusion of metal ions (Na or K ) from the running buffer into the crown ether units, the stationary phases become positively charged and can provide extra electrostatic interaction with ionizable solutes and enhance the dipolar interaction with polar neutral solutes. This enhances the host-guest interaction with the solute and improves chiral recognition and enantioselectivity. Due to the cooperation of the anchored b-CD and the crown ether, this kind of crown ether capped b-CD bonded phase shows better enantioselectivity than either b-CD-or crown ether bonded phases only. These new types of stationary phases have good potential for fast chiral separation with CEC.Introduction. ± Separation of enantiomers is one of the most active areas of chromatography [1 ± 3] and is important in various fields [4 ± 6], e.g., natural-product research, stereospecific synthesis, development of chiral drugs in the pharmaceutical industry, and in environmental studies. Chromatographic methods are typically employed for chiral separation, including high-performance liquid chromatography (HPLC) [7], gas chromatography (GC) [8], micellar electrokinetic capillary chromatography (MECC) [9] and, more recently, capillary electrochromatography (CEC) [10]. To improve chiral separation, two approaches can be used: a) optimization of chromatographic conditions, and b) use of new chiral stationary phases (CSPs) or chiral additives in the mobile phase.GC and LC were the first tools to be employed in the separation of enantiomers [4]. However, conventional LC cannot utilize small particles and/or long columns to obtain high efficiencies because of the pressure limitations of normal pumping systems. Although GC usually offers higher efficiencies than LC due to the larger number of available theoretical plates, most chiral compounds of interest have low volatilities. This limits the use of GC for chiral separations [10]. During the last several years, capillary electrophoresis (CE) has become a powerful technique for chiral separations when chiral selectors are added to the running buffers [11]. CEC is a modern liquid chromatography technique combining the high efficiency of CE with the high selectivity usually obtained by HPLC [2]. The mobile phase is transported through a Helvetica Chimica Acta ± Vol. 85 (2002) 3283 capillary containing the stationary phase by means of electro-osmosis instead of pressure. Neutral solutes are separated by partitioning between the...

show abstract

Crown ether capped cyclodextrin used as stationary phase for capillary gas chromatography

Cited by 9 publications

References 17 publications

Cooperative self-assembly and molecular binding behavior of cyclodextrin–crown ether conjugates mediated by alkali metal ions

Cooperative self-assembly and molecular binding behavior of cyclodextrin–crown ether conjugates mediated by alkali metal ions

Determination of the enantiomer and positional isomer impurities in atomoxetine hydrochloride with liquid chromatography using polysaccharide chiral stationary phases

Enantiomeric Separations in Capillary Electrochromatography with Crown Ether-Capped -Cyclodextrin-Bonded Silica Particles as Chiral Stationary Phase

Contact Info

Product

Resources

About