Determination of the Enantiomeric Composition of Chiral Amines Based on the Quenching of the Fluorescence of a Chiral Calixarene

Grady, Teresa; Harris, Stephen J.; Smyth, Malcolm R.; Diamond, Dermot; Hailey, Perry A.

doi:10.1021/ac960383c

Cited by 92 publications

(47 citation statements)

References 21 publications

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“…Figure 5 illustrates the Stern-Volmer plots for the quenching of the fluorescence of calixarene L1 (0.7 µmol dm -3 in methanol), upon addition of 0% S-PA: 100% R-PA, 50% S-PA: 50% R-PA (racemic mix) and 100% S-PA: 0% R-PA respectively, at a concentration range of 0 -25mmol dm Previous results show that it is possible to discriminate between the enantiomers of chiral amines with appropriately arranged hydrogen bonding groups, chiral centres and quenching sites using suitably functionalised calix [4]arenes 14,15 . The position of the chiral centre relative to the hydrogen bonding groups and the aryl group in the guest molecule appears to be vitally important, illustrated by the fact that the calix [4]arene host L1 does not discriminate between enantiomers of phenylglycinol without an extra methylene spacer between the chiral centre and phenyl ring, while excellent discrimination is observed with phenylalaninol, with a methylene spacer 6 .…”

Section: Variation Of Stern-volmer Plot With Enantiomeric Compositionmentioning

confidence: 99%

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Varying solvent polarity to tune the enantioselective quenching of a calixarene host

Lynam

Diamond

2005

J. Mater. Chem.

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Calixarene L1 has been designed to behave as a fluorescent molecular sensor capable of distinguishing between chiral amines on the basis of their size and chirality.Fluorescence quenching studies of calixarene L1 in methanol demonstrated no enantiomeric selectivity for a short chain amino alcohol, phenylglycinol, while excellent selectivity was observed for a longer chain amino alcohol, phenylalaninol (PA). The effect of solvent on the fluorescent properties of this calixarene in the presence of PA has been studied, and demonstrates that varying solvent polarity allows the wavelength of enantiomer selectivity to be tuned from 227nm to 440nm. While enantiomeric selectivity is observed in methanol at 227nm, no discrimination is achieved in acetonitrile. Chiral discrimination is statistically possible with L1 and PA in chloroform at 227nm, but it is not comparable with the extent of discrimination achieved in methanol. In chloroform a new emission band at a longer wavelength (440nm) is formed with R-PA in solution with L1, an effect that is not observed with the S-enantiomer. This new band in chloroform at 440nm allows very effective chiral discrimination and has been attributed to the presence of two different conformations of calixarene L1, which is reinforced by 1 H-NMR studies and molecular modelling studies.__________________________________________________________________________

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Section: Variation Of Stern-volmer Plot With Enantiomeric Compositionmentioning

confidence: 99%

“…In previous work it has been shown that calixarenes 9,10,11,12 and more recently fluorescent calixarenes 13,14,15 can discriminate between enantiomers. Here we present how solvent polarity has an effect not only on the extent of enantiomeric discrimination, but also on the wavelength at which discrimination occurs.…”

Section: Introductionmentioning

confidence: 99%

Varying solvent polarity to tune the enantioselective quenching of a calixarene host

Lynam

Diamond

2005

J. Mater. Chem.

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“…Calixarenes for instance, which have been the subject of much synthetic developments, are making inroads into analytical and separation techniques. They will be useful not only for fluorescence based detection schemes for metal ions but for organics such as amines for instance [194].…”

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Luminescence in organized media and supramolecular interactions:physicochemical aspects and applications

Lerner¹,

Martín²

2000

Analusis

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Introduction Molecular luminescence of analytes in organized media or in supramolecular complexes of cyclodextrinsThe photophysical and photochemical behaviour of molecules complexed to cyclodextrins (CD) is generally different from their behaviour in solution. The first observations in the field were qualitative and were related to the increased stabilisation of labile molecules, mostly drugs, against photodegradation when complexed to natural cyclodextrins [1]. Complexation by CD's was then the preferred subject for those involved in supramolecular chemistry and drug vectorisation techniques [2] as well as in separation techniques [3][4][5]. Stabilization of a molecule against photochemical degradation is still very important in the field of pharmaceutical sciences. A recent example is the stabilisation of promazine as an inclusion complex with β-cyclodextrin [6]. Other photochemists were attracted quite early to this field of research and initiated studies, which were mostly photophysical in nature [7,8]. The key observation was that the formation of supramolecular complexes of analytes with cyclodextrins (CDs) resulted in an increase of their fluorescence quantum yield or even in the appearance of room temperature phosphorescence (RTP) [9][10][11][12]. This enhancement has been used to increase the sensitivity and the selectivity in both luminescence and chromatographic techniques [13-15].We will not say more about RTP with CDs as the subject will be developed in another contribution in the same issue of this Journal. However RTP is also observed in the solubilization of analytes in micellar colloïdal solutions and this field will be reviewed hereunder.These properties have been used to develop analytical techniques, which combine the selectivity of complexation with an enhanced emission [16][17][18][19]. In this way an improvement in the detection limits is obtained in many separation techniques such as HPLC, capillary electrophoresis (CE) or planar chromatography. Furthermore these molecular interactions allow to reveal or to stabilize new molecular forms or to turn species which are normally non-emitting into luminescent ones. All these aspects are reviewed hereunder after a short summary on the nature of the intermolecular interactions, which lie at the heart of these effects. Nature of the interactions between an analyte and a CD or a micelleWithout going into a thorough analysis of the origin of the interactions which exist between molecules in dense media which concern us here, it seems useful to recall the most important factors which should be taken into account when any type of luminescence, fluorescence or phosphorescence is involved.

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“…Sensing devices, which can differentiate between different enantiomers, would be a cheaper, easier way of carrying out this work. The McKervey group in colaboration with the Diamond group have been involved in studies carried out with (S)-di-napthylprolinolcalix [4]arene which has shown excellent chiral discrimination between the enantiomers of phenylglycinol, phenylethylamine and norephedrine 34 . The mechanism of transduction in this example is based on the fluorescence quenching of the napthylprolinol handles of the calixarene upon comlpexation with the R-enatiomer of phenylglycinol.…”

Section: Calixarenes As Chiral Recognition Devicesmentioning

confidence: 99%

Important calixarene derivatives – their synthesis and applications

McMahon¹,

O'Malley²,

Nolan³

et al. 2003

Arkivoc

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Since their discovery as by-products in the phenol-formaldehyde condensation to prepare bakelites, the calixarenes have gained much attention for their application as both surfactants and chemoreceptors. The McKervey group has been a leader in the development and synthesis of new and novel calixarenes for use as ion-complexing agents as well as for use in many other applications. Many calixarene derivatives prepared by the McKervey group are being used in both environmental and biomedical monitoring. This review covers both the synthesis and sensor applications of the various calixarenes developed by the McKervey group over the past two decades, with emphasis on metal cation detection.

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Determination of the Enantiomeric Composition of Chiral Amines Based on the Quenching of the Fluorescence of a Chiral Calixarene

Cited by 92 publications

References 21 publications

Varying solvent polarity to tune the enantioselective quenching of a calixarene host

Varying solvent polarity to tune the enantioselective quenching of a calixarene host

Luminescence in organized media and supramolecular interactions:physicochemical aspects and applications

Important calixarene derivatives – their synthesis and applications

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