Binding characteristics of native cyclofructan 6 and its derivatives with metal ions

Na, Yun-Cheol; Padivitage, Nilusha; Dissanayake, Milan K.; Armstrong, Daniel W.

doi:10.1080/10610278.2013.852676

Cited by 4 publications

(6 citation statements)

References 29 publications

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“…Derivatization disrupts hydrogen bonding between the 3‐OH groups and, this in turn, increases the interactions with guest molecules. In addition, the presence of derivatized groups provides more interaction sites .…”

Section: Resultsmentioning

confidence: 99%

Combined use of cyclofructans and an amino acid ester‐based ionic liquid for the enantioseparation of huperzine A and coumarin derivatives in CE

Stavrou

Breitbach

Kapnissi‐Christodoulou

2015

Electrophoresis

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Cyclofructans (CFs) and their derivatives have recently been proven to be efficient chiral selectors (CSs) for the enantioseparation of several analytes in CE, HPLC, and GC. In this study, the chiral separation ability of a number of native and derivatized CFs was examined in CE. Particularly, six different CFs, with different derivatization groups and cavity sizes [native CF-6 and CF-7, isopropyl cyclofructan-6 (IPCF-6), IPCF-7, sulfated cyclofructan-6 (SCF-6), and SCF-7] were used as CSs for the enantioseparation of huperzine A, warfarin, and coumachlor. Almost all of the examined CFs, except from SCF-6 & -7, demonstrated relatively low and sometimes no chiral separation ability for huperzine A. In an effort to improve both resolution and efficiency, the chiral ionic liquid D-Alanine tert butyl ester lactate (D-AlaC4Lac) was added into the BGE. In most of the cases, the combination of CF with D-AlaC4Lac resulted in an improvement in peak efficiency and/or resolution. When CF-6 was utilized with D-AlaC4Lac, a resolution of 1.4 was obtained, while the use of IPCF-6/D-AlaC4Lac provided a baseline enantioseparation. Although the combination of SCF-7 and 40 mM D-AlaC4Lac did not affect resolution, it dramatically increased peak efficiency from 24,000 to 117,000. In the case of warfarin and coumachlor, IPCF-6 and IPCF-7 proved to be the most effective CSs. It is, therefore, concluded that the size of the cavity and the CF derivatization are the key parameters for the chiral separation capability. It is also clear from this study that D-AlaC4Lac is necessary for improved peak efficiencies and resolutions.

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Section: Resultsmentioning

confidence: 99%

Combined use of cyclofructans and an amino acid ester‐based ionic liquid for the enantioseparation of huperzine A and coumarin derivatives in CE

Stavrou

Breitbach

Kapnissi‐Christodoulou

2015

Electrophoresis

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“…CF6 associates much less strongly with alkali cations than with Ba 2+ or Pb 2+ . However, the addition of 10 mM alkali cation to the 50 mM ammonium acetate, pH 5 buffer containing 80 mM CF6 did increase the BHP atropoisomer resolution (Table ).…”

Section: Resultsmentioning

confidence: 99%

“…It is known that crown ethers can bind with metal cations forming clathrates . Native CFs and derivatized CFs were found to have binding capability toward a variety of metal cations .…”

Section: Introductionmentioning

confidence: 99%

Cation‐enhanced capillary electrophoresis separation of atropoisomer anions

Berthod

Armstrong

2015

Electrophoresis

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CE was used to study the separation of the atropoisomers of four phosphoric acids and two sulfonic acids and the enantiomers of two phosphoric acids. All solutes are in their anionic forms in aqueous electrolytes. The chiral additives were two hydroxypropyl cyclodextrins (CDs) and cyclofructan 6 (CF6). The CDs were able to separate four solutes and the CF6 additive could separate only one: 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (BHP). Since CF6 is able to bind with cations, nitrate of alkaline metals, Ba(2+) , and Pb(2+) were added, greatly improving the BHP separation at the expense of longer migration times. There seems to be a link between CF6-cation-binding constants and BHP resolution factors. Cation additions were also performed with CD selectors that are less prone to form complexes with cations. Significant improvements of enantiomer or atropoisomer separations were observed also associated with longer migration times. It is speculated that the anionic solutes associate with the added cations forming larger entities better differentiated by CDs.

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“…22 On account of the favorable binding of alkyland arylammonium ions within the [18]crown-6 core, in addition to the existence of well-defined functional groups that provide the source of secondary and tertiary interactions, native CF-6 and its derivatives have been used widely as chiral stationary phases for the separation of the enantiomers of chiral amines and other molecules. 23 Although CF-6 was isolated and characterized over three decades ago and shown to bind with Group IA, 24 IIA, 25 and transition 25,26 metal cations in both gas and solution phases, it is somewhat surprising that its coordinative chemistry with metal cations has not been investigated with regard to possible superstructures that are expected to exist in the crystalline state. We envisioned that the coordination of CF-6 with a specific metal cation, in a way similar to that of the complexation of [18]crown-6 with a K + ion (Figure 1c), could rigidify conformationally flexible CF-6 so that the metal cations might act as SBUs and assist in the assembly of CF-6 to form well-defined superstructures in the solid state.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Although CF-6 was isolated and characterized over three decades ago and shown to bind with Group IA, IIA, and transition , metal cations in both gas and solution phases, it is somewhat surprising that its coordinative chemistry with metal cations has not been investigated with regard to possible superstructures that are expected to exist in the crystalline state. We envisioned that the coordination of CF-6 with a specific metal cation, in a way similar to that of the complexation of [18]crown-6 with a K + ion (Figure c), could rigidify conformationally flexible CF-6 so that the metal cations might act as SBUs and assist in the assembly of CF-6 to form well-defined superstructures in the solid state.…”

Section: Resultsmentioning

confidence: 99%

Metal-Assisted Carbohydrate Assembly

Wu,

Tang,

Lee

et al. 2024

J. Am. Chem. Soc.

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The sequence-controlled assembly of nucleic acids and amino acids into well-defined superstructures constitutes one of the most revolutionary technologies in modern science. The elaboration of such superstructures from carbohydrates, however, remains elusive and largely unexplored on account of their intrinsic constitutional and configurational complexity, not to mention their inherent conformational flexibility. Here, we report the bottom-up assembly of two classes of hierarchical superstructures that are formed from a highly flexible cyclo-oligosaccharide�namely, cyclofructan-6 (CF-6). The formation of coordinative bonds between the oxygen atoms of CF-6 and alkali metal cations (i) locks a myriad of flexible conformations of CF-6 into a few rigid conformations, (ii) bridges adjacent CF-6 ligands, and (iii) gives rise to the multiple-level assembly of three extended frameworks. The hierarchical superstructures present in these frameworks have been shown to modulate their nanomechanical properties. This research highlights the unique opportunities of constructing convoluted superstructures from carbohydrates and should encourage future endeavors in this underinvestigated field of science.

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Binding characteristics of native cyclofructan 6 and its derivatives with metal ions

Cited by 4 publications

References 29 publications

Combined use of cyclofructans and an amino acid ester‐based ionic liquid for the enantioseparation of huperzine A and coumarin derivatives in CE

Combined use of cyclofructans and an amino acid ester‐based ionic liquid for the enantioseparation of huperzine A and coumarin derivatives in CE

Cation‐enhanced capillary electrophoresis separation of atropoisomer anions

Metal-Assisted Carbohydrate Assembly

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