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Differentiation of Chiral Compounds Using NMR Spectroscopy

Differentiation of Chiral Compounds Using NMR Spectroscopy

Thomas J. Wenzel

ISBN: 978-1-119-32391-4

Jul 2018

592 pages


An updated guide to the most current information available for determining how to use NMR spectroscopy to differentiate chiral compounds 

Differentiation of Chiral Compounds Using NMR Spectroscopy offers a thoroughly revised second edition to the essential volume that puts the focus on the chiral systems that are commercially available and have been widely vetted for use in NMR spectroscopy. The text covers a broad range of reagents that make it possible to determine the enantiomeric purity and assign the absolute configuration of many classes of compounds.

Comprehensive in scope, the text describes the chiral NMR differentiating agents as derivatizing agents, solvating agents, metal-based reagents and liquid crystals and gels, and explains the range and types of compounds for which they can be used for analysis. New to this edition are the most recent findings in the field as well as the development of advanced NMR measurement techniques that allow for the simplification of complex spectra resulting in more readily identified enantiodifferentiation. This important resource:

  • Includes the most recent coverage of a large range of compounds that can be analyzed using chiral NMR reagents
  • Explores the use of chiral NMR reagents and explains their relationship to the stereochemistry of the analyzed molecules
  • Offers the essential information needed to help decide which method is the best NMR method to apply to a class or molecules
  • Contains experimental strategies for using the reagents that are likely to improve the quality of the results

Differentiation of Chiral Compounds Using NMR Spectroscopy is a comprehensive guide designed for investigators planning to use NMR spectroscopy to determine enantiomeric purity or assign the absolute configuration of a compound.



Chapter 1. Introduction

1.1. Chiral derivatizing agents (CDAs)

1.2. Chiral solvating agents (CSAs)

1.3. NMR methods to improve the quality of data with CSAs and CDAs

1.4. Overview of chiral reagents and methodologies

Chapter 2. Aryl-containing Carboxylic Acids

2.1 Introduction

2.2. ƒÑ-Methoxy-ƒÑ-trifluoromethylphenylacetic acid (MTPA - Mosher’s reagent)

2.2.1. Analysis of secondary alcohols

2.2.2. Analysis of secondary diols and polyols

2.2.3. Analysis of primary alcohols

2.2.4. Analysis of tertiary alcohols

2.2.5. Analysis of secondary amines

2.2.6. Analysis of primary amines

2.2.7. Use as a chiral solvating agent

2.2.8. Preparation of MTPA derivatives

2.3. Ą-Methoxy-Ą-trifluoromethylphenylacetic thioic acid

2.4. Ą-Methoxyphenylacetic acid (MPA)

2.4.1. Analysis of secondary alcohols Variable temperature method for assigning absolute stereochemistry Barium(II) method for assigning absolute stereochemistry

2.4.2. Analysis of diols

2.4.3. Analysis of 1,2,3-primary,secondary,secondary-triols

2.4.4. Analysis of primary alcohols

2.4.5. Analysis of amines Barium(II) method for assigning absolute stereochemistry

2.4.6. Analysis of amino alcohols

2.4.7. Analysis of sulfoxides

2.4.8. Polymer bound CDAs – the “mix and shake” method

2.5. Mandelic acid (2-hydroxy-2-phenyl acetic acid) - (MA)

2.6. O-Acetyl mandelic acid (2-acetoxy-2-phenyl acetic acid) (O-AMA)

2.7. Other O-derivatized mandelic acids

2.8. 2-Phenylpropionic acid (2-PPA)

2.9. 2-Phenylselenopropionic acid

2.10. 2-methoxy-2-phenylpent-3-ynoic acid

2.11. 3-Phenylbutanoic acid (3-PBA)/2-phenylbutanoic acid (2-PBA)

2.12. Ą-Cyano-Ą-fluorophenylacetic acid (CFPA)/Ą-cyano-Ą-fluoronaphthylacetic acid (CFNA)/Ą-cyano-Ą-fluoro-p-tolylacetic acid (CFTA)

2.13. N-Boc phenylglycine (BPG)

2.14. 1,5-Difluoro-2,4-dinitrobenzene and derivatives

2.14.1. N-(5-fluoro-2,4-dinitrophenyl)-1-phenylethylamide

2.15. 2-Fluoro-2-phenylacetic acid/2-fluoro-2-(1-naphthyl)propionic acid/2-fluoro-2-(2-naphthyl)propionic acid

2.16. Ą-Methoxy-Ą-(1-naphthyl)acetic acid (1-NMA)/Ą-methoxy-Ą-(2-naphthyl)acetic acid (2-NMA)

2.17. 2-tert-Butoxy-2-(2-naphthyl)acetic acid (2-NTBA)

2.18. (-)-(R)-(2-Naphthyloxy)phenylacetic acid

2.19. Ą-Methoxy-Ą-trifluoromethyl-1-naphthylacetic acid (MTN(1)A)

2.20. Naproxen

2.21. 2-Methoxy-2-(1-naphthyl)propionic acid (MĄNP)

2.21. O-Aryl lactic acids

2.22. Ą-(2-anthryl)-Ą-methoxyacetic acid (2-AMA)/Ą-(9-anthryl)-Ą-methoxyacetic acid (9-AMA)

2.23. Summary

2.23.1. Analysis of primary alcohols

2.23.2. Analysis of secondary alcohols

2.23.3. Analysis of tertiary alcohols

2.23.4. Analysis of primary amines

2.23.5. Analysis of secondary amines

2.23.6. Analysis of secondary thiols

Chapter 3. Other Carboxylic Acid-Based Reagents

3.1. Camphanic acid

3.2. Menthoxyacetic acid (MAA)

3.3. Tetra-tert-butyltrioxabicyclo[3.3.1]nonadienedicarboxylic acid

3.4. Di-O-benzoyl tartaric acid/di-O-p-toluoyl tartaric acid

3.5. 2-(2,3-Anthracenedicarboximido)cyclohexane carboxylic acid

3.6. 3ƒÒ-Acetoxy-ƒ´5-etiocholenic acid

3.7. 1-Methoxy-2,3-dihydro-1H-cyclopenta[a]naphthalene-1-carboxylic acid

3.8. 1-Fluoroindan-1-carboxylic acid

3.9. (-)-(R)-2-(2,3,4,5,6-Pentafluorophenoxy)-2-phenyl-d5)acetic acid

3.10. 2,2-Diphenyl- and 2,2-di-2-naphthalen-2-yl[1,3]dioxolane-4,5-dicarboxylic acid

3.11. Tetrahydro-1,4-epoxynaphthalene-1-carboxylic acid

3.12. 2-tert-butyl-2-methyl-1,3-benzodioxole-4-carboxylic acid

3.13. Benzo[de]isoquinoline 1,3-dione amino acids

3.14. Amino acids and derivatives

3.14.1. Fmoc-tryptophan(Boc)-OH

3.14.2. Phosphonomethyl-L-proline

3.14.3. Phenylalanine methyl ester and phenylalanine

3.14.4. Proline

3.14.5. N-(2-nitrophenyl)proline

3.14.6. N-arylcarbonyl pseudo prolines

3.15. 2-Methylbutyric acid

3.16. Axial chiral carboxylic acids

3.16.1. 2’-Methoxy-1,1’-binaphthyl-2-carboxylic acid (MBNC)

3.16.2. 2’-Methoxy-1,1’-binaphthalene-8-carboxylic acid

3.16.3. 2-(2’-Methoxy-1’-naphthyl)-3,5-dichlorobenzoic acid

Chapter 4. Hydroxyl- and Thiol-Containing Reagents

4.1. 2,2,2-Trifluorophenylethanol (TFPE)/2,2,2-trifluoro-1-(9-anthryl)ethanol (TFAE)

4.1.1. Analysis of sulfoxides

4.1.2. Analysis of sulfinamides, sulfinates, sulfites and thiosulfates

4.1.3. Analysis of lactones

4.1.4. Analysis of lactams

4.1.5. Analysis of epoxides and oxaziridines

4.1.6. Analysis of N,N’dialkylarylamine oxides

4.1.7. Analysis of amino acid derivatives

4.1.8. Analysis of imines

4.1.9. Analysis of allenes

4.1.10. Analysis of other compounds

4.1.11. Use of lanthanide chelates with TFPE and TFAE

4.1.12. Use as chiral derivatizing agents

4.2. Other anthryl-based reagents

4.2.1. Analogues of TFAE

4.2.2. Ethyl-2-(9-anthryl)-2-hydroxyacetate (9-AHA)

4.2.3. 2-(2,3-Anthracenedicarboximido)-1-cyclohexanol

4.3. 1-Phenylethanol

4.4. 2-Methoxy-2-phenylethanol

4.5. Methyl mandelate (MM)

4.6. Mandelonitrile

4.7. Ethyl mandelate

4.8. Aminoindanols

4.9. Menthol

4.10. Trans-bis(hydroxydiphenylmethyl)-2,2-dimethyl-1,3-dioxacyclopentane

4.11. (S)-Ethyl lactate

4.12. Assignment of absolute configuration using glycosidation shifts

4.12.1. Analysis of di- and polysaccharides

4.12.2. ƒÒ-D- and ƒÒ-L-Fucofuranoside

4.1. 2-Butanol and 2-octanol

4.14 Axial chiral (atropoisomeric) alcohols

4.14.1. 2,2’-Dihydroxy-1,1’-binaphthalene (BINOL)

4.14.2. (S)-3,3’-Dibromo-1,1’-bi-2-naphthol

4.14.3. 4,4’6,6’-Tetrachloro-2,2’-bis(hydroxydiphenylmethyl)biphenyl

4.15. Diol and dithiol reagents

4.15.1. Butane-2,3-diol and butane-2,3-thiol

4.15.2. Epigallocatechin-3-O-gallate

Chapter 5. Amine-based Reagents

5.1. Primary amines

5.1.1. 1-Phenylethylamine (PEA)/1-(1-naphthyl)ethylamine (NEA)/1-(9-anthryl)ethylamine (AEA)

5.1.2. N,N,4-trimethyl-2-{[1-phenylethyl}(1-naphthyl)methyl]amine

5.1.3. Fluorinated aryl amines

5.1.4. (1S,2S)-1-Phenyl-2-amino-3-methoxy-1-propanol

5.1.5. Phenylglycinol

5.1.6. 5-Amino-4-aryl-2,2-dimethyl-1,3-dioxans

5.1.7. Amino acids Peptides Phenylglycine methyl ester (PGME)/phenylglycine dimethylamide

5.1.8. 1-Methoxy-2-aminopropane

5.1.9. (S,S)-1,2-[(9,10-dihydro-9,10-ethanoanthracen-11-yl)methyl]dipyrrolidine/(R)-N-(((12R)-9,10-dihydro-9,10-ethanoanthracen-12-yl)methyl)-1-phenylethan-1-amine

5.1.10. (+)-Dihydroabietylamine derivatives

5.2. Secondary Amines

5.2.1. Ephedrine

5.2.2. (+)-(R)-N-benzyl-Ą-methylbenzylamine (BMBA)

5.2.3. 2-Methyl piperidine

5.2.4. (N-Methyl)-Ą-isoparteinium cation

5.2.5 (S)-2-(Methoxymethyl)pyrrolidine

5.2.6. (S)-Triazine selector

5.3. Tertiary Amines

5.3.1. Derivatives of Troger’s base

5.4. Diamine reagents

5.4.1. 1,2-Diphenyl-1,2-diaminoethane

5.4.2. N,N’-Substituted 1,2-diphenyl-1,2-diaminoethane

5.4.3. Derivatives of trans-1,2-diaminocyclohexane

5.4.4. cis-1,3-Diamino-trans-4-fluorocyclopentane

5.5. Databases using amine CSAs

5.5.1. N,Ą-Dimethylbenzylamine (DMBA)

5.5.2. Bis-1,3-methylbenzylamine-2-methylpropane (BMBA-pMe)

5.5.3. (Rƒwƒ{ƒÑ-Methoxy-ƒÑ-trifluoromethylphenylacetic acid (MTPA)/BMBA-pMe

Chapter 6. Miscellaneous CDAs, CSAs and Other Methods of Chiral Analysis

6.1. Amides

6.1.1. N-(3,5-Dinitrobenzoyl)-1-phenylethylamine (DNB-PEA)/N-(3,5-Dinitrobenzoyl)-1-(1-naphthyl)ethylamine (DNB-NEA)

6.1.2. N-((S)-1-(3,5-bis(trifluoromethyl)phenyl)ethyl)-3,5-dinitrobenzamide

6.1.3. N-(3,5-Dinitrobenzoyl)-L-leucine (DNB-Leu)

6.1.4. N-(3,5-Dinitrobenzoyl)-4-amino-3-methyl-1,2,3,4-tetrahydrophenanthrene (Whelk-O-1)

6.1.5. N-1-(1-Naphthyl)ethyltrifluoroacetamide

6.1.6. exo-N-[(1R,2R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl)benzamides

6.2. Lactam and lactam-like compounds

6.2.1. (S)-1-benzyl-6-methylpiperazine-2,5-dione

6.2.2. (S)-1-isopropyl-6-(4-nitrobenzyl)-piperazine-2,5-dione

6.2.3. 2-Oxazolidinones

6.2.4. 5-Methyl-5-phenylpyrroline N-oxide

6.3. Aldehydes

6.3.1. 2-Hydroxy-2’-nitrobenzoate-3-aldehyde-1,1’-binaphthalene

6.3.2. (-)-Myrtenal

6.3.3. Lactate-derived aldehyde

6.3.4. (S)-Citronellal

6.3.5. 2-Hydroxy-2’-substituted-3-aldehyde-1,1’-binaphthalene

6.3.6. Helicin (salicylaldehyde ƒÒ-D-glucoside)

6.3.7. 2’-Methoxy-1,1’-binaphthalene-8-carbaldehyde

6.4. Ketones

6.4.1. l-Menthone

6.5. Anhydrides

6.5.1. (S)-(+)-2-Methylbutyric anhydride

6.5.2. (1-Naphthyl)(trifluoromethyl) O-carboxy-anhydride

6.6. Carbonate with (2,6-dichloro-4-methoxyphenyl) and (2,4-dichlorophenyl) groups

6.7. 2,2-Dimethoxypropane

6.8. Isocyanates and isothiocyanates

6.8.1. 1-Phenylethyl isocyanate

6.8.2. 1-(1-Naphthyl)ethyl isocyanate

6.8.3. Ą-Methoxy-Ą-(trifluoromethyl)benzyl isocyanate

6.8.4. Phenylethyl isothiocyanate/naphthylethyl isothiocyanate

6.8.5. (1S,2S)-N-[(2-isothiocyanato)cyclohexyl]trifluoromethane sulfonamide

6.9. Thioureas

6.10. Sulfur-containing reagents

6.10.1. Camphor-10-sulfonic acid

6.10.2. (p-Tolyl) (2-(1-hydroxy-1-trifluoromethyl-2,2,2-fluoroethyl)phenyl)sulfoxide

6.10.3. Disulfonimide derivative of 2,2’-dihydroxy-1,1’-binaphthalene

6.10.4. (N-Methylphenylsulfoximidoyl)methyl lithium

6.11. Reagents that react at a chlorine atom

6.11.1. 5(R)-Methyl-1-(chloromethyl)-2-pyrrolidinone

6.11.2. Menthyl chloroformate

6.11.3. 2’-Methoxy-1,1’-binaphthalene-2-carbohydroxymoyl chloride (MBCC)

6.12. Polyfunctional reagents

6.12.1. Quinine

6.12.2. Quinine derivatives

6.12.3. Cinchonidine

6.12.4. Quinidine

6.12.5. Quinidine derivatives

6.12.6. (S)-2-(5-bromo-2-dimethylaminobenzylamino)-1,1,3-triphenylpropan-1-ol

6.12.7. 2[(2R)-2-hydroxy-3-[[(1S)-1-phenylethyl]amino]propyl]isoindoline-1,3-dione

6.12.8. (S,S)-[(2-benzyloxynaphthalen-1-yl)phenylmethyl](1-phenylethyl)amine

6.12.9. 2-Amino-2-phenyl-1-ethanol

6.12.10. (S)-Diphenyl(pyrrolidin-2-yl)methanol

6.12.11. 2’-Amino-1,1’-binaphthalene-2-ol

6.12.12. Urea derivative of trans-1,2-diaminocyclohexane

6.12.13. Poly-N-substituted glycines

6.12.14. Proline derivative

6.12.15. 1-(1-Naphthyl)ethyl urea derivatives of amino acids

6.12.16. (S)-1-[1H-benzo(d)(1,2,3)triazol-1-yl]-2-[6-methoxynaphthalen-2-yl-propan-1-one]

6.12.17. Benzene tricarboxamide-based hydrogelator

6.12.18. (1S,2S)-N,N’-dihydroxy-N,N’-bis(diphenylacetyl)-1,2-cyclohexanediamine

6.12.19. 1-Formyl-N-(2-methoxy-1,2-diphenylethyl)piperidine-2-carboxamide

6.12.20. 2,2’-Dihydroxybenzophenone

6.12.21. Diisopropyl-L-tartrate

6.13. Micelles

6.14. Ionic liquids

6.15. Guanosine monophosphate (G-tetrads)

6.16. Achiral reagents for chiral analysis: N21,N23-dibenzyl-5,10,15,20-tetrakis(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidene)porphyrinogen

6.17. Assigning absolute configuration using kinetic resolution catalysts

6.18. Chiral analysis through isotope labeling

6.19. Self-induced diastereomeric anisochronism (SIDA): Self-differentiation of chiral compounds

6.20. High-throughput methods with chiral NMR reagents

6.20.1. Analysis of enantiopurity

6.20.2. Selection of the optimal CSA

6.21. HPLC-NMR

6.22. Database methods

Chapter 7. Reagents Incorporating Phosphorus, Selenium, Boron, and Silicon Atoms

7.1. Phosphorus-containing reagents

7.1.1. Phosphorus(V) reagents Phosphinic amides Thiophosphoramides Phosphinothioic acids O-ethyl phenylphosphonothioic acid cis-2-Chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazophospholidin-2-one 2-Chloro-5,5-dimethyl-4-phenyl-1,3,2-dioxaphosphorinane-2-oxide 2-Chloro-3-phenyl-1,3,2-diazaphosphabicyclo[3.3.0]octane-2-oxide Methyl phosphonic dichloride/methyl phosphonothioic dichloride 1,1’-Binaphthyl-2,2’-diylphosphoric acid 1,1’-Binaphthyl-2,2’-diylphosphoroselenoyl chloride

7.1.2. Phosphorus(III) reagents Diazaphospholidines 1,3,2-Dioxaphospholanes (1R,2S,5R)-Menthyloxydiphenylphosphine Phosphorus trichloride [5] HELOL phosphite

7.1.3. Ionic reagents TRISPHAT/BINPHAT Phosphorus zwitterion

7.1.4. Configurational analysis of phosphates: Oxygen isotope methods

7.1.5. Summary

7.2. Selenium-containing reagents

7.2.1. 4-Methyl-5-phenyloxazolidine-2-selone

7.2.2. bis-Selenourea

7.2.3. (S)-3-phenyl-2-(selenophenyl)propan-1-ol

7.2.4. (R)-1-(phenylselanyl)butan-2-amine

7.2.5. 2-Phenylselenopropionic acid

7.3. Boron-containing reagents

7.3.1. 2-Formylphenylboronic acid (FPBA)

7.3.2. 2-(1-Methoxyethyl)phenylboronic acid

7.3.3. 1,3-Phenyldiboronic acid

7.3.4. Trialkoxyboranes

7.3.5. Chiral diborate

7.4. Silyl-containing reagents

7.4.1. Monochlorosilanes

Chapter 8. Macrocyclic and Receptor Compounds as Chiral NMR Differentiating Agents

8.1. Cyclodextrins

8.1.1. Introduction

8.1.2. Native cyclodextrins Lanthanide coupling to native cyclodextrins

8.1.3. Neutral cyclodextrin derivatives Hexakis(2,3,6-tri-O-Methyl)-ƒÑ-cyclodextrin (TM-ƒÑ-CD)/Heptakis(2,3,6-tri-O-Methyl)-ƒÒ-cyclodextrin (TM-ƒÒ-CD) Heptakis[2,3-di-O-methyl-6-O-(L-valine-tert-butylamide-NƒÑ-ylcarbonylmethyl)]-ƒÒ-cyclodextrin Heptakis(2-O-methyl-3-O-acetyl-6-hydroxy)-ƒÒ-cyclodextrin Benzoylated and benzylated cyclodextrins Carbamoylated cyclodextrins Octakis(3-O-butanoyl-2,6-di-O-pentyl)-ƒ×-cyclodextrin Hydroxyethyl (HE-CD) and hydroxypropyl (HP-CD) cyclodextrins Heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-ƒÒ-cyclodextrin

8.1.4. Anionic cyclodextrin derivatives Carboxymethylated cyclodextrins (CM-CD) Octakis(2,3-di-O-methyl-6-O-carboxymethyl)-ƒ×-cyclodextrin Heptakis(6-carboxymethylthio-6-deoxy)-ƒÒ-cyclodextrin (6-CMT-ƒÒ-CD) Sulfobutylether- (SBE-CD) and sulfopropylether (SPE-CD) cyclodextrins Phosphated cyclodextrins (P-CD) Sulfated cyclodextrins (S-CD)

8.1.5. Cationic cyclodextrin derivatives Amino-substituted cyclodextrins Diaminomethylated-Ą-cyclodextrin (DAM-CD) O-(2-hydroxypropyl)trimethylammonium (TMA-CD)/O-(2-hydroxypropyl)triethylammonium (TEA-CD)/O-(2-hydroxypropyl)tri-n-propylammonium (TPA-CD) cyclodextrins

8.1.6. Summary

8.2. Crown ethers

8.2.1. Introduction

8.2.2. (18-Crown-6)-2,3,11,12-tetracarboxylic acid

8.2.3. (18-Crown-6) with 1,2:5,6-isopropylidine-D-mannitol unit

8.2.4. Crown ethers incorporating a 2,2’-dihydroxy-1,1’-binaphthalene unit

8.2.5. Glycoside-derived crown ethers

8.2.6. Crown ethers derived from maleopimaric acid

8.2.7. P-Stereogenic diphosphacrowns

8.2.8. Aza-oxo crown ether-like compounds

8.2.9. Aza-containing macrocycles

8.3. Calixarenes and resorcinarenes

8.3.1. Introduction

8.3.2. Resorcinarenes

8.3.3. Calixarenes

8.3.4. Summary

8.4. Receptor compounds

8.4.1. For carboxylic acids

8.4.2. For carbohydrates

8.5. Cyclosophoraoses: cyclic-ƒÒ-D-glucans

8.6. Cryptophane receptor

8.7. 1,1’-Binaphthalene-based macrocycles and receptors

Chapter 9. Chiral Differentiation with Metal-Based Reagents

9.1. Introduction

9.2. Lanthanide complexes

9.2.1. Introduction

9.2.2. Strategies to compensate for peak broadening with lanthanide shift reagents Use of diamagnetic lanthanide complexes Use of samarium(III) complexes 13C NMR spectra Use of polar solvents Raising the temperature Signal processing techniques

9.2.3. Catalytic properties of lanthanide ions

9.2.4. Application of lanthanide shift reagents

9.2.5. Assignment of absolute stereochemistry

9.2.6. Pr(III) complex of tetraphenylimidodiphosphinate – Pr(tpip)3

9.2.7. Bimetallic lanthanide-silver reagents Analysis of organic salts

9.2.8. Aqueous lanthanide shift reagents Complexes of propylenediamine tetraacetate (pdta) Complexes of N,N,N’,N’-tetrakis(pyridylmethyl)propylene diamine (tppn) Complexes with other ligands Complexes with tetraazocyclodecane and tetraazocyclododecane macrocyclic ligands

9.3 Transition metal complexes

9.3.1. Palladium complexes Bridged dimers with amine ligands Miscellaneous palladium complexes

9.3.2. Platinum Complexes Complexes with amine ligands C,P-Cycloplatinated phosphite complex Complexes with diphosphine ligands

9.3.3. Rhodium complexes Rhodium dimer [Rh2(MTPA)4] Miscellaneous rhodium complexes

9.3.4. Cobalt complexes Complexes with porphyrin ligands Analysis of geometrical isomers Analysis of DNA

9.3.5. Zinc complexes

9.3.6. Ruthenium complexes

9.3.7. Silver complexes

9.3.8. Tin complexes

9.3.9. Titanium complexes

9.3.10. Aluminum complexes

9.3.11. Gold nanoparticles

9.3.12. Iron complexes

9.3.13. Tellurium-iron complex

Chapter 10. Chiral NMR Differentiation Using Ordered Systems

10.1. Introduction

10.2. Chiral liquid crystals and gels

10.2.1. Introduction

10.2.2. Practical aspects of using chiral aligning media

10.2.3. Early studies with liquid crystals

10.2.4. Aligning media

10.2.5. Enantiopurity analysis of 2H labeled compounds

10.2.6. Natural abundance 2H NMR analysis: NMR methods

10.2.7. Applications of natural abundance 2H NMR spectroscopy

10.2.8. 13C NMR applications

10.2.9. 1H and 13C NMR methods

10.2.10. 19F NMR analysis

10.2.11. Analysis using other nuclei

10.2.12. Analysis of prochiral compounds

10.2.13. Analysis of prochiral methylene groups of fatty acids – 2H/1H positions and ratios

10.2.14. Assignment of absolute configuration Residual dipolar couplings (RDCs) Residual chemical shift anisotropy (RCSA) Residual quadrupolar couplings (RQCs).

10.3. Polymers

10.4. Solid-state NMR spectroscopy

10.4.1. Analysis of polymer-bound compounds

Chapter 11: Closing Comments and Future Prospects

11.1. Selection of CSAs and CDAs

11.2. Future propsects

11.2.1. New chiral reagents

11.2.2. Chiral NMR analysis using only instrumental methods