Separation of racemiccloso-3,3-(η3,2-norbornadienyl)rhodacarboranes into enantiomers by HPLC on chiral stationary phasesinto enantiomers by HPLC on chiral stationary phases

Il’in, M. M.; Zinevich, T. V.; Pisareva, I. V.; Chizhevsky, I. T.; Davankov, V. A.

doi:10.1007/bf02495500

Cited by 5 publications

(6 citation statements)

References 6 publications

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“…These are as follows: (i) the protonation of the PPN + salts of the corresponding anionic closo-{ 4 -(C 7 H 7 -2-CR 2 OH)}rhodacarborane complexes with HPF 6 (synthesis of 111a-g), (ii) the thermal reaction in benzene between carbinols NBD-2-CR 2 OH (R = H or Me) and the Scheme 42. Synthesis of closo-( 3 , 2 -norbonadienyl)rhodacarboranes 111a-k [17,18,70,89] Using chiral stationary phase HPLC, racemic complexes 111a, b, h and 113 were successfully resolved into enantiomers and their chiroptical properties (rotation angles and CD spectra) were investigated [87]. closo-( 3 , 2 -Norbonadienyl)rhodacarboranes with mono-C-substituted carborane ligands were usually formed in the reactions as mixture of diastereomers.…”

Section: Metallacarboranes With η 3 η 2 -Cycloallylolefinic-type Ligmentioning

confidence: 99%

“…In a series of papers, we have reported our results on the synthesis [17,18,70,[87][88][89][90], structural and stereochemical studies [87][88][89][90], and the application in catalysis [90][91][92][93] of closo-(-norbonadienyl)rhodacarboranes based on [7,nnido-C 2 B 9 H 11 ] 2− derivatives (n = 8 or 9). Thus, complexes of the type [ [17,70] were prepared by three different synthetic methods.…”

Section: Metallacarboranes With η 3 η 2 -Cycloallylolefinic-type Ligmentioning

confidence: 99%

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Large-cage (11–13-vertex) dicarbon metallacarboranes of platinum metals with mono- and polycyclic diolefin ligands

Chizhevsky

2007

Coordination Chemistry Reviews

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Section: Metallacarboranes With η 3 η 2 -Cycloallylolefinic-type Ligmentioning

confidence: 99%

Section: Metallacarboranes With η 3 η 2 -Cycloallylolefinic-type Ligmentioning

confidence: 99%

Large-cage (11–13-vertex) dicarbon metallacarboranes of platinum metals with mono- and polycyclic diolefin ligands

Chizhevsky

2007

Coordination Chemistry Reviews

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“…In the published HPLC separations of boron cluster species,21, 24–34 the term enantiomers is used for the sterically different forms of the asymmetric boron cluster compounds. However, in the stereochemistry of organic species, this term denotes sterically different forms of species, whose asymmetry is caused by one atomic centre of asymmetry, see, e.g.…”

Section: Chromatographic Separationsmentioning

confidence: 99%

“…Published chiral separations of boron cluster species by HPLC24–34 have been motivated by the need to prove the suspected chirality of the species and to obtain pure atropoisomer fractions of the compounds for further studies, e.g. circular dichroism measurements30 or absolute structure determination by X‐ray crystallography30.…”

Section: Chromatographic Separationsmentioning

confidence: 99%

“…Nevertheless, this has been represented by only one reported example, where γ‐CD was effectively used for a chiral separation of the boron cluster compounds. The second type of a complex from the meta series, closo‐ 2,2‐(η 3,2 −C 7 H 7 ‐2‐CH 2 )‐2,1,7‐RhC 2 B 9 H 11 ), was separated into atropoisomers by HPLC on the hydroxypropyl ß‐CD stationary phase 33. For the structures of the resolved half sandwich compounds, see Figure 6.…”

Section: Chromatographic Separationsmentioning

confidence: 99%

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Emerging subject for chiral separation science: Cluster boron compounds

Horáková

Grüner

Vespalec³

2010

Chirality

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The structural chirality is an inherent feature of fully synthetic boron cluster compounds that sometimes exhibit unique biochemical effects. HPLC studies with zwitter-ionic cluster boron compounds and electrophoretic studies with boron cluster anions reveal that the chiral separability of these species is remarkably dissimilar to that of organic species, if uncharged cyclodextrins are used as chiral selectors. Furthermore, marked differences were found between the analytical characteristics of the chiral separations of the boron cluster species and those of the organic species with uncharged cyclodextrins. The present-day experimental database indicates that the rules valid for the chiral separations of the organic species cannot be applied to the chiral separations of the boron cluster species without experimental verification. The current extent of research work devoted to the investigation of chirality and chiral separations of boron cluster species is negligibly small in comparison with that devoted to the investigation of chirality and chiral separations of organic species. This makes difficult a reliable explanation of both the particularities observed in chiral separations of boron cluster species with cyclodextrins as chiral selectors and the strange effects related to these separations at the moment.

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Determination of enantiomeric purity of 1-substituted 3-amino-1,2-dicarba-closo-dodecaboranes by HPLC on chiral stationary phases

et al. 2008

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A determination of enantiomeric purity of 1 substituted (Me, Ph, and Pr i ) 3 amino 1,2 dicarba closo dodecaboranes by HPLC on chiral Chiralcel OD H and Chiralpac AD stationary phases involving preliminary phthaloylation of 3 aminocarboranes has been suggested as a general method.Carboranes, including dicarba closo dodecaboranes, are considered as compounds prospective for the develop ment of medicinal agents, especially for the boron neutron capture therapy (BNCT) of cancer. 1-5 Biological activity of such compounds should depend on their stereochemical structure. However, properties of chiral carboranes have not yet been studied. The reason for this is that the chemi cal methods for the preparation and identification of indi vidual carborane stereoisomers, the spatial isomerism of which is provided by arrangement of substituents in the carborane cage, are not yet enough developed.High performance liquid chromatography (HPLC) is widely used for separation and analysis of a great variety of cage organoboron compounds. 6 Thus, a separation of a number of 1 substituted 1,2 dicarba closo dodecabo ranes has been accomplished by reversed phase HPLC, 7 investigation have been made on separation of cobalt con taining boranes, 8 as well as of 1,2 dicarba closo dodeca borane derivatives using gel permeation chromatography and styrene divinylbenzene copolymer as the sorbent. 9At present, HPLC, in particular, HPLC on chiral sta tionary phases (CSP) remains the most important ana lytical instrument in chemistry of organoboron com pounds. 10-16 Phases based on β cyclodextrin (β CD), both the modified (acetyl β CD for a reversed phase chroma tography) and unmodified were used as the CSP. Analyti cal results on a wide number of chiral carboranes and met aloboranes showed a high efficiency of these CSP. Though Chiralcel OD H and Chiralpac AD are used for the sepa ration of enantiomers of various organic and organo element compounds, 17 in the literature, the data on their use for the analysis of chiral cage organoboron compounds are absent.The purpose of the present work is to study possibilities of application of HPLC on Chiralcel OD H and Chi ralpac AD chiral phases for the separation of planary chiral 1 substituted 3 amino 1,2 dicarba closo dodeca boranes 1-3. Results and DiscussionEarlier, 18-20 we have developed approaches to the preparation of individual stereoisomers of 1 methyl (1) and 1 phenyl 3 amino 1,2 dicarba closo dodecaborane (2). To determine enantiomeric purity of compounds, we used HPLC (on silica gel, a Lichrosorb Si 60 column) and 1 H NMR spectroscopy with preliminary derivatization of 3 amino 1,2 dicarba closo dodecaborane derivatives 1 and 2 with chiral derivatizing agents (CDA), viz., (S) naproxen acyl chloride, frequently used for this pur pose, 21-30 or N tosyl L proline and N phthaloyl L ala nine chlorides. 19,20The individual enantiomers of 3 amino 1 methyl o carborane 1 were isolated through the resolution of its

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Separation of racemiccloso-3,3-(η3,2-norbornadienyl)rhodacarboranes into enantiomers by HPLC on chiral stationary phasesinto enantiomers by HPLC on chiral stationary phases

Cited by 5 publications

References 6 publications

Large-cage (11–13-vertex) dicarbon metallacarboranes of platinum metals with mono- and polycyclic diolefin ligands

Large-cage (11–13-vertex) dicarbon metallacarboranes of platinum metals with mono- and polycyclic diolefin ligands

Emerging subject for chiral separation science: Cluster boron compounds

Determination of enantiomeric purity of 1-substituted 3-amino-1,2-dicarba-closo-dodecaboranes by HPLC on chiral stationary phases

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