Chirality effects in the chemical ionization mass spectra of dialkyl tartrates

Winkler, F. J.; Ståhl, Daniel; Maquin, F.

doi:10.1016/s0040-4039(00)84011-3

Cited by 34 publications

(19 citation statements)

References 14 publications

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“…In the first of these, chiral selectivity is probed through the differences in abundance of diastereomeric protonbound complexes generated in the gas phase [5] by means of chemical ionization (CI), [6,7] fast atom bombardment (FAB), electrospray ionization (ESI), or matrix-assisted laser desorption ionization (MALDI). [7,8] Another technique is based on ion-molecule reactions.…”

Section: Introductionmentioning

confidence: 99%

Generation and Reactivity of Enantiomeric (BINOLato)Ni⁺ Complexes with Chiral Secondary Alcohols in the Gas Phase

Novara

Gruene

Schröder

et al. 2008

Chemistry A European J

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In the presence of secondary alcohols, electrospray ionization of dilute methanolic solutions of nickel(II) salts and 1,1'-bis-2-naphthol (BINOL) leads to complexes of the formal composition [(BINOLato)Ni(CH3CH(OH)R)]+ (BINOLato refers to a singly deprotonated (R)- or (S)-1,1'-bis-2-naphthol ligand; R=CH3, C2H5, n-C3H7, n-C4H9, n-C5H11, n-C6H13, c-C6H11, and C6H5). Upon collision-induced dissociation, each mass-selected nickel complex either loses the entire secondary alcohol ligand or undergoes bond activation followed by elimination of the corresponding ketone, as revealed by deuterium labeling. When enantiomeric BINOLato ligands (R or S) are combined with chiral secondary alcohols (R or S), differences in the branching ratios between these channels for the two stereoisomers of the secondary alcohols provide insight into the chiral discrimination operative in the C--H- and O--H-bond activation processes. For saturated alkan-2-ols, the chiral discrimination is low, and if any preference is observed at all, ketone elimination from the homochiral complexes (R,R and S,S) is slightly favored. In contrast, the diastereomeric (BINOLato)Ni+ complexes of 1-phenylethanol exhibit preferential ketone losses for the heterochiral systems (S,R and R,S).

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Section: Introductionmentioning

confidence: 99%

Generation and Reactivity of Enantiomeric (BINOLato)Ni⁺ Complexes with Chiral Secondary Alcohols in the Gas Phase

Novara

Gruene

Schröder

et al. 2008

Chemistry A European J

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“…The minimum energy conformations are illustrated in Fig. 3 [74]. Association to form the heterochiral pair results in a weaker H-bonding interaction at an extreme of the ziptype chelate complex proposed.…”

Section: Gas Phase Molecular Recognition Properties Of Tartratesmentioning

confidence: 99%

“…Association to form the heterochiral pair results in a weaker H-bonding interaction at an extreme of the ziptype chelate complex proposed. This is further explained by a weak dialkyl -gauche interaction formed when the enantiomers having opposite configurations bind through a proton, resulting in a less favorable association of tartrate-esters [74].…”

Section: Gas Phase Molecular Recognition Properties Of Tartratesmentioning

confidence: 99%

Molecular recognition properties of tartrates and metal‐tartrates in solution and gas phase

Wijeratne

Schug²

2009

J of Separation Science

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“…[4][5][6] Although this approach presents various fundamental problems (to be discussed in detail below), and equilibrium conditions could not be guaranteed, the results were promising. Tartrates have been studied both by chemical ionization (CI) [4][5][6] and by fast-atom bombardment, 7,9 the two techniques yielding very similar 'relative stability constants'.…”

Section: There Are Four Possible Forms (Rr; Ss; Rs and Sr)mentioning

confidence: 99%

“…25 The simplest approach is to characterize complex formation directly, in a way analogous to equilibrium constant determination by CI [4][5][6] or by ICR 22 :…”

Section: Hostmentioning

confidence: 99%

Chiral Recognition Via Host-Guest Interactions Detected by Fast-atom Bombardment Mass Spectrometry: Principles and Limitations

Dobó

Lipták

Huszthy

et al. 1997

Rapid Commun. Mass Spectrom.

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An intensity function combining peak intensities in the same manner as that in which equilibrium constants combine ion activities is suggested for characterization of enantioselectivity by fast-atom bombardment mass spectrometry. The intensity function combined with the use of two internal standards, one similar to the host, one to the guest compounds is shown to give excellent results: The enantioselectivity is better by up to factor of 10 than that obtained using one internal standard only, and its reproducibility is ca. a factor of 10 better, than that obtained using relative peak intensities (the RPI method). © 1997 by John Wiley & Sons, Ltd. Received 2 March 1997; Revised 14 April 1997; Accepted 14 April 1997 Rapid. Commun. Mass Spectrom. 11, 889-896 (1997 Mass spectrometry is not normally concerned with distinction between enantiomers (optically active compounds whose molecular structures are non-superimposable mirror images of one another, labelled by D or L according to their optical rotation, by + or -in the original Fischer notation, or by R or S in the CahnPrelog-Ingold system). These are, in fact, distinguishable only through probing with plane-polarized light or through interactions with reactants which also contain chiral centres. In the present work possible approaches for enantiomer distinction by mass spectrometry are summarized and one of them is improved.The first example in which enantiomers were distinguished by mass spectrometry was described 20 years ago in the case of diisopropyl tartrate.1 In the electron impact spectrum proton-bound tartrate dimers were observed, probably formed by self chemical ionization. There are four possible forms (R,R; S,S; R,S and S,R). Among these R,R plus S,S form an enantiomeric pair, having identical chemical and physical properties. Likewise, R,S and S,R form another enantiomeric pair. The 'homochiral' dimers (R,R or S,S) are diastereomers of the 'heterochiral' ones (R,S or S,R), and are physically and chemically distinguishable from either or both members of the other enantiomeric pair by ordinary means (melting points, chemical reactivity, spectroscopy, fast-atom bombardment (FAB) mass spectrometry, etc.). It was found that, in the mass spectra, ion intensities of the 'homo-chiral' tartrate dimers were higher than those of the 'hetero-chiral' ones, indicating higher stability of the former. Following this initial study the tartrate system has been studied in detail 2-9 using deuterium labelled compounds. Ion intensities were combined to yield what were termed 'relative stability constants'. [4][5][6] Although this approach presents various fundamental problems (to be discussed in detail below), and equilibrium conditions could not be guaranteed, the results were promising. Tartrates have been studied both by chemical ionization (CI) 4-6 and by fast-atom bombardment, 7,9 the two techniques yielding very similar 'relative stability constants'.Chemical ionization using optically active reagent gases have often been used for other compounds as well.2,10-15 A...

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Chirality effects in the chemical ionization mass spectra of dialkyl tartrates

Cited by 34 publications

References 14 publications

Generation and Reactivity of Enantiomeric (BINOLato)Ni⁺ Complexes with Chiral Secondary Alcohols in the Gas Phase

Generation and Reactivity of Enantiomeric (BINOLato)Ni⁺ Complexes with Chiral Secondary Alcohols in the Gas Phase

Molecular recognition properties of tartrates and metal‐tartrates in solution and gas phase

Chiral Recognition Via Host-Guest Interactions Detected by Fast-atom Bombardment Mass Spectrometry: Principles and Limitations

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Chirality effects in the chemical ionization mass spectra of dialkyl tartrates

Cited by 34 publications

References 14 publications

Generation and Reactivity of Enantiomeric (BINOLato)Ni+ Complexes with Chiral Secondary Alcohols in the Gas Phase

Generation and Reactivity of Enantiomeric (BINOLato)Ni+ Complexes with Chiral Secondary Alcohols in the Gas Phase

Molecular recognition properties of tartrates and metal‐tartrates in solution and gas phase

Chiral Recognition Via Host-Guest Interactions Detected by Fast-atom Bombardment Mass Spectrometry: Principles and Limitations

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Generation and Reactivity of Enantiomeric (BINOLato)Ni⁺ Complexes with Chiral Secondary Alcohols in the Gas Phase

Generation and Reactivity of Enantiomeric (BINOLato)Ni⁺ Complexes with Chiral Secondary Alcohols in the Gas Phase